Aaron Seah Wei Ming; Isaac Seow-En; Koo Chee Hoe; Lionel Raphael Chen Hui; Yvonne Ng Ying Ru; Ngo Nye Thane; Ivan Tan En-Howe; Rachel Lee Shi Yi; Emile Kwong Wei Tan

doi:10.3393/ac.2025.01508.0215

Articles

Page Path: HOME > Ann Coloproctol > Volume 42(3); 2026 > Article

Original Article Minimally invasive surgery Robotic versus laparoscopic surgery for mid and low rectal cancer: a propensity score–matched analysis of short-term outcomes and costs: Aaron Seah Wei Ming¹, Isaac Seow-En¹, Koo Chee Hoe¹, Lionel Raphael Chen Hui¹, Yvonne Ng Ying Ru¹, Ngo Nye Thane², Ivan Tan En-Howe³, Rachel Lee Shi Yi³, Emile Kwong Wei Tan¹; Annals of Coloproctology 2026;42(3):355-363.
DOI: https://doi.org/10.3393/ac.2025.01508.0215
Published online: June 16, 2026

¹Department of Colorectal Surgery, Singapore General Hospital and National Cancer Centre, Singapore

²Department of Pathology, Singapore General Hospital, Singapore

³Group Finance Analytics, Singapore Health Services, Singapore

Correspondence to: Emile Kwong Wei Tan, MBBS, FRCS Department of Colorectal Surgery, Singapore General Hospital and National Cancer Centre, Outram Rd, Singapore 169608 Email: emilekwtan@gmail.com

• Received: December 7, 2025 • Revised: February 8, 2026 • Accepted: February 25, 2026

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

prev next

861 Views
26 Download
1 Web of Science
1 Crossref
1 Scopus

Full Article

Download PDF

Abstract
INTRODUCTION
METHODS
RESULTS
DISCUSSION
ARTICLE INFORMATION
REFERENCES

Abstract

Purpose
Robotic and laparoscopic approaches to rectal cancer surgery yield comparable short-term outcomes; however, comparative inpatient costs, particularly when stratified by tumor level, remain insufficiently characterized. This study compared short-term clinical and pathological outcomes, as well as index hospitalization costs, for minimally invasive surgery in patients with mid and low rectal cancer.
Methods
All consecutive patients with mid (5–10 cm from the anal verge) and low (<5 cm from the anal verge) rectal cancer who underwent elective minimally invasive surgery between January 2018 and December 2023 were identified. One-to-one propensity score matching was performed using the following covariates: age, sex, body mass index, American Society of Anesthesiologists physical status, tumor level, receipt of neoadjuvant therapy, and presence of a defunctioning stoma. Outcomes and cost components were compared overall and stratified by tumor level.
Results
After matching, 282 patients were included (laparoscopic surgery, n=141; robotic surgery, n=141). Median operative time was longer in the robotic group (368 minutes vs. 325 minutes, P=0.007), whereas the median postoperative length of stay was similar between groups (6.0 days vs. 6.0 days, P=0.255). Rates of conversion to open surgery, anastomotic leak, 30-day mortality, and 30-day readmission did not differ significantly. Histopathological indicators of resection quality, including lymph node yield, margin clearance, and completeness of total mesorectal excision, were comparable. Mean index hospitalization cost was higher in the robotic group (SGD 37,436 vs. SGD 31,724; difference, SGD 5,713; P=0.008), with a greater difference observed in mid rectal cancer (SGD 8,606; P=0.008) than in low rectal cancer (SGD 1,811; P=0.465).
Conclusion
Robotic and laparoscopic surgery yielded comparable short-term clinical and pathological outcomes. Although costs were higher with robotic surgery, the cost differential was smaller for low rectal cancer, identifying this subgroup as a priority for prospective evaluation of clinical and economic value.
Keywords: Rectal neoplasms; Minimally invasive surgical procedures; Robotics; Laparoscopy; Costs and cost analysis

INTRODUCTION

Rectal cancer accounts for approximately one-third of all colorectal malignancies worldwide [1]. Total mesorectal excision (TME) remains the cornerstone of curative surgical management, and the quality of mesorectal dissection is a key determinant of local control and oncological outcomes [2, 3]. Surgery for rectal cancer is technically demanding, particularly within the confined pelvic space, where achieving optimal oncological resection while preserving function presents substantial operative challenges. Over the past 2 decades, minimally invasive approaches have been increasingly adopted to improve perioperative recovery while maintaining oncological integrity.

Minimally invasive approaches are now widely used for rectal cancer resection, with randomized trials and meta-analyses demonstrating comparable short-term and oncological outcomes between laparoscopic and open surgery [4, 5]. Despite these favorable findings, laparoscopic rectal surgery remains technically challenging, particularly in the deep and narrow pelvis, where restricted instrument articulation, limited visualization, and suboptimal ergonomics may compromise the precision of mesorectal dissection [6].

Robotic platforms were developed to address these limitations by providing 3D visualization, wristed instrumentation, and improved ergonomic stability [7, 8]. Randomized trials and meta-analyses indicate that robotic and laparoscopic rectal cancer surgery yield similar rates of complete TME, circumferential resection margin involvement, lymph node harvest, and perioperative morbidity and mortality [7, 9]. Although some meta-analyses report lower conversion rates and modest technical advantages with robotic surgery, these findings have not consistently translated into improved cost-effectiveness compared with conventional laparoscopic surgery [10–12].

More recently, the REAL randomized clinical trial, conducted in high-volume centers and focused specifically on mid and low rectal cancer, reported comparable oncological outcomes between robotic and laparoscopic surgery while demonstrating lower conversion rates and improved technical performance of the robotic platform in selected settings. These findings suggest that the relative advantages of robotic surgery may be context-dependent, particularly in technically demanding pelvic dissection [13].

Most comparative studies have evaluated rectal cancer as a single anatomical entity without stratifying outcomes by tumor level [7, 9–11]. However, surgical complexity and technical demands may differ substantially between mid and low rectal tumors, particularly with respect to pelvic access, sphincter preservation, and the conduct of TME. Consequently, whether the relative performance and cost profiles of robotic and laparoscopic approaches vary systematically by tumor level remains insufficiently characterized in the existing literature.

Accordingly, this study aimed to compare short-term clinical outcomes, pathological quality of resection, and inpatient costs between robotic and laparoscopic minimally invasive surgery for mid and low rectal cancer using propensity score matching, with subgroup analyses stratified by tumor location. As the choice of operative platform increasingly influences institutional resource allocation and patient access, clarifying whether the relative clinical and cost performance of robotic and laparoscopic approaches differs by tumor level has important implications for surgical decision-making and healthcare resource utilization in rectal cancer care.

METHODS

Ethics statement

This study was approved by the Institutional Review Board of Singapore General Hospital (No. 2022/2639). Informed consent was waived due to the use of deidentified data and the retrospective nature of the study.

Study design and patient selection

We conducted a retrospective cohort study using a prospectively maintained institutional surgical database and included all consecutive patients who underwent elective minimally invasive rectal resection with TME for curative intent between January 2018 and December 2023. Eligible patients had mid or low rectal carcinoma, defined as tumors located ≤10 cm from the anal verge, and underwent surgery at the Department of Colorectal Surgery, Singapore General Hospital, and the National Cancer Centre Singapore. Patients who underwent emergency surgery, open surgery, transanal total mesorectal excision (TaTME), or multivisceral resection were excluded to ensure procedural comparability between operative platforms.

Tumor level was determined using preoperative magnetic resonance imaging (MRI). Mid rectal cancers were defined as tumors located 5–10 cm from the anal verge, and low rectal cancers as those located <5 cm from the anal verge. The choice of surgical approach (robotic vs. laparoscopic) was based on the surgeon’s discretion and expertise, reflecting routine clinical practice at our institution.

Enhanced Recovery After Surgery (ERAS) protocols were implemented throughout the study period. These included prehabilitation, preoperative carbohydrate supplementation when not contraindicated, early removal of orogastric tubes, minimization of routine drain placement, and early postoperative mobilization, in accordance with established perioperative care guidelines [14].

All procedures were performed by subspecialty-trained colorectal surgeons, each performing more than 50 minimally invasive colorectal resections annually. Robotic procedures were initially conducted using the da Vinci Si Surgical System (Intuitive Surgical), employing a double-docking technique for splenic flexure mobilization. Following the institutional platform transition, the da Vinci Xi system (Intuitive Surgical) replaced the Si system after 2022 and was subsequently used for all robotic rectal resections.

Data collection and study variables

Preoperative variables included age, sex, body mass index (BMI), tumor distance from the anal verge, American Society of Anesthesiologists (ASA) physical status, and receipt of neoadjuvant therapy. Intraoperative variables included the type of procedure performed, surgical approach (laparoscopic vs. robotic), operative time, and unplanned conversion to open surgery. Postoperative outcomes included length of hospital stay, 30-day mortality, 30-day readmission, and anastomotic leak. Anastomotic leak was defined by clinical suspicion with radiologic confirmation and/or the need for reoperation. Histopathological outcomes were used as surrogates of surgical quality and included lymph node yield, distal and radial resection margin clearance, and macroscopic completeness of TME, graded according to established specimen assessment criteria [15].

Clinical management

Preoperative investigations included colonoscopy with biopsy, routine laboratory testing, thoracic and abdominal computed tomography, and pelvic MRI. Patients with locally advanced disease were considered for neoadjuvant therapy, consisting of either total neoadjuvant therapy or long-course chemoradiotherapy before definitive surgical resection. TME was performed in all cases. Abdominoperineal resection was performed when sphincter-preserving surgery was not oncologically or technically feasible because of invasion of the sphincter complex or levator ani muscles.

Statistical analysis

Baseline characteristics were compared between the laparoscopic and robotic groups using bivariate analyses to assess covariate imbalance. Propensity score matching was performed to reduce selection bias and adjust for baseline differences. The propensity model included age, sex, BMI, ASA physical status, tumor location (mid vs. low rectum), receipt of neoadjuvant therapy, and presence of a defunctioning stoma. These variables were selected a priori on the basis of their established associations with surgical complexity, perioperative risk, and surgeon selection of the operative platform.

One-to-one nearest-neighbor matching without replacement was performed using a caliper width of 0.05 times the standard deviation of the logit of the propensity score. Covariate balance before and after matching was assessed using standardized mean differences (SMDs), with an SMD of <0.10 considered indicative of adequate balance.

Continuous variables were assessed for normality of distribution. Normally distributed variables were compared using the Student t-test, whereas nonnormally distributed variables were compared using the Mann-Whitney U-test. Categorical variables were compared using the chi-square test or Fisher exact test, as appropriate. All tests were 2-sided, and P<0.05 was considered statistically significant. Continuous variables are presented as median (interquartile range, IQR), categorical variables as frequency (percentage), and cost variables as mean values. All data were recorded in Microsoft Excel (Microsoft Corp) and analyzed using IBM SPSS ver. 27.0 (IBM Corp).

Cost analysis

Cost data were obtained from institutional finance records and analyzed in the propensity score–matched cohort. Costs are reported as index hospitalization costs and were subdivided into operative costs (operating room utilization and consumables), inpatient ward costs (high-dependency and general ward charges), and inpatient treatment costs (investigations and allied health services). Costs were analyzed from the institutional provider perspective and reflect direct medical expenditures only. They were calculated before government subsidies or insurance coverage and therefore do not represent patient out-of-pocket payments. Thirty-day readmission costs were analyzed separately and excluded from index hospitalization totals, whereas outpatient costs were not included. All monetary values are reported as means in Singapore dollars (SGD) at 2023 price levels; an exchange rate of SGD 1=US $0.74 is provided for interpretability.

RESULTS

Patient characteristics and perioperative outcomes

During the 72-month study period, 383 patients underwent elective minimally invasive surgery for mid and low rectal cancer. Overall cohort characteristics are summarized in Table 1. After propensity score matching, 282 patients were included, with 141 patients in each group (Fig. 1). All matched variables were well balanced between the groups, and SMDs indicated adequate post-matching covariate balance (Table 2).

Post-matching short-term clinical and histopathological outcomes are presented in Table 3. Median operative time was significantly longer in the robotic group than in the laparoscopic group (368 minutes [IQR, 300–465 minutes] vs. 325 minutes [IQR, 256–400 minutes]; P=0.007). Median postoperative length of stay did not differ significantly between the approaches (6.0 days [IQR, 4–7 days] vs. 6.0 days [IQR, 5–8 days]; P=0.255).

Rates of conversion to open surgery, anastomotic leak, 30-day mortality, and 30-day readmission also did not differ significantly between groups. Histopathological outcomes, including lymph node yield and clearance of the radial and distal resection margins, were comparable between cohorts. Macroscopic assessment showed similar distributions of complete, near complete, and incomplete specimens in the 2 groups.

Post-matching causes of 30-day readmission are summarized in Table 4. Overall readmission rates did not differ significantly between groups (P=0.069). Among readmitted patients, surgery-related indications accounted for a significantly greater proportion of readmissions in the robotic group than in the laparoscopic group (93.9% vs. 61.9%, P=0.009), whereas medical complications were more common in the laparoscopic group (6.1% vs. 38.1%, P=0.009). Stoma-related complications were the most frequent cause of readmission in both groups and occurred at similar proportions (42.4% vs. 52.4%, P=0.579), with high stoma output accounting for most stoma-related readmissions (39.4% vs. 52.4%, P=0.407). Adhesive small bowel obstruction occurred more frequently in the robotic cohort (30.3% vs. 4.8%, P=0.036). Other causes of readmission, including superficial surgical site infection, intra-abdominal collection, and anastomotic leak, were infrequent and did not differ significantly between approaches.

Cost analysis

In the propensity score–matched cohort, mean index hospitalization costs were higher in the robotic group than in the laparoscopic group for the overall population with mid and low rectal cancer (SGD 37,436 vs. SGD 31,724, P=0.008), driven primarily by higher operative expenditure (Table 5, Fig. 2). Thirty-day readmission costs were numerically higher in the robotic group but did not reach statistical significance (Table 5).

In subgroup analyses by tumor location, mean index hospitalization costs remained higher in the robotic group for both mid and low rectal cancers. The cost difference was greater in mid rectal cancer (SGD 38,792 vs. SGD 30,186; difference, SGD 8,606; P=0.008) than in low rectal cancer (SGD 35,553 vs. SGD 33,743; difference, SGD 1,811; P=0.465) (Table 5, Fig. 2). Differences in inpatient ward and inpatient treatment costs between approaches were not statistically significant in either subgroup. Thirty-day readmission costs were numerically higher in the robotic group across subgroups but were not statistically significant (Table 5).

DISCUSSION

In this propensity score–matched analysis of minimally invasive surgery for mid and low rectal cancer, robotic and laparoscopic approaches demonstrated broadly comparable short-term clinical outcomes. Postoperative length of stay was comparable after propensity score matching.

Operative duration was significantly longer in the robotic cohort, consistent with findings from multiple systematic reviews and meta-analyses comparing robotic and laparoscopic rectal surgery [7, 10, 11, 16]. Although operative time may decrease with increasing institutional experience and continued advances in robotic platforms, such temporal effects were not specifically evaluated in the present study.

In the propensity score–matched cohort, 54 patients (19.1%) were readmitted within 30 days of discharge, with a numerically higher proportion in the robotic group than in the laparoscopic group (33 patients vs. 21 patients, P=0.069). Surgery-related causes accounted for a significantly greater proportion of readmissions in the robotic cohort, whereas medical causes were more frequent in the laparoscopic cohort. Stoma-related complications were the most common indication for readmission in both groups and occurred at similar proportions after matching, with high stoma output representing the predominant contributor. This finding is consistent with existing evidence showing that dehydration secondary to high-output ileostomy is a leading cause of early readmission after rectal cancer surgery and stoma formation [17].

Because rates of defunctioning stoma formation were balanced after matching, the observed distribution of readmissions is unlikely to be attributable solely to baseline case mix and may instead reflect the underlying postoperative risk profile of mid and low rectal cancer surgery, particularly among patients undergoing neoadjuvant therapy or sphincter-preserving procedures. Similar patterns of stoma-related early readmission have been reported in prior analyses from our institution focusing on low rectal cancer surgery [18].

Adhesive small bowel obstruction was observed more frequently in the robotic cohort. This finding should be interpreted cautiously given the small number of events and the possibility of residual confounding. Because the present study was not designed to evaluate mechanistic contributors to postoperative adhesive obstruction, this observation warrants confirmation in larger prospective datasets.

From an economic perspective, our findings are consistent with the existing literature showing that higher procedural expenditure remains the principal driver of the increased index hospitalization costs associated with robotic, as compared with laparoscopic, rectal surgery. In the present matched cohort, robotic surgery was associated with higher mean costs overall; however, the magnitude of this difference varied by tumor location, with a substantially smaller cost differential observed in low rectal cancer than in mid rectal cancer. Although the narrower cost gap in low rectal tumors may reflect the greater technical demands of deep pelvic dissection, where the advantages of robotic visualization, articulation, and ergonomic stability may be more relevant, nonoperative cost components did not differ significantly between approaches, and the overall difference remained primarily driven by operative expenditure.

These observations are consistent with broader economic evaluations of minimally invasive colorectal surgery. A recent systematic review and Bayesian network meta-analysis by Chok et al. [12] showed that robotic surgery is generally associated with higher direct costs without clear superiority in short-term clinical outcomes across colorectal procedures, underscoring the importance of identifying clinical contexts in which the relative value of robotics may differ. Emerging high-quality randomized evidence, including the REAL trial, suggests that in high-volume centers and technically demanding mid and low rectal cancer surgery, robotic platforms may offer advantages in selected technical outcomes, such as lower conversion rates and improved operative performance [13]. These findings raise the possibility that the clinical and economic balance of robotic surgery may be context-dependent, particularly in anatomically challenging pelvic surgery.

Taken together, our subgroup findings suggest that the relative cost disadvantage of robotic surgery may be attenuated in technically complex low rectal resections, although this hypothesis requires cautious interpretation and prospective validation. With ongoing technological refinement, increasing surgeon experience, and the emergence of additional robotic platforms, reductions in capital and consumable costs may further influence the long-term economic profile and accessibility of robotic rectal surgery.

Our study is among the few to evaluate short-term clinical, histopathological, and inpatient cost outcomes of minimally invasive rectal cancer surgery with explicit stratification by tumor level. All procedures were performed within a specialized colorectal surgery unit by high-volume surgeons, thereby enhancing procedural consistency within a relatively large institutional cohort.

Limitations

This study has several limitations. First, its retrospective design introduced the possibility of residual confounding despite the use of propensity score matching, and unmeasured factors such as pelvic anatomy, tumor morphology on preoperative imaging, surgeon-specific platform preferences, and temporal changes in perioperative practices may have influenced both operative approach selection and outcomes. Second, the available follow-up duration limited the analysis to short-term clinical and pathological outcomes, and long-term oncological and functional outcomes could not be assessed. Third, the cost analysis was restricted to index hospitalization from an institutional provider perspective and did not incorporate quality of life–based utility measures required for formal cost-effectiveness modeling, such as the incremental cost-effectiveness ratio. Fourth, transfusion data and certain perioperative variables were not consistently available for retrospective extraction and therefore could not be included in the analysis. Furthermore, because this study was conducted within a high-volume subspecialty colorectal unit, the findings may not be fully generalizable to lower-volume centers, institutions at earlier stages of robotic adoption, or healthcare systems with different cost structures. Prospective studies with longer follow-up and formal economic evaluation are warranted to further define the clinical and economic value of robotic surgery in rectal cancer.

Conclusions

Robotic and laparoscopic approaches yielded comparable short-term clinical and pathological outcomes in minimally invasive surgery for mid and low rectal cancer. The smaller cost differential observed in low rectal cancer identifies this subgroup as a priority for prospective evaluation of the clinical and economic value of robotic surgery relative to laparoscopy.

ARTICLE INFORMATION

Conflict of interest

Emile Kwong Wei Tan is an editorial board member of this journal, but was not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflict of interest relevant to this article was reported.

Funding

None.

Author contributions

Conceptualization: ASWM, ISE, LRCH, KCH, YNYR, EKWT; Data curation: ASWM; Formal analysis: ASWM, NNT, ITEH, RLSY, EKWT; Methodology: ASWM, ISE, EKWT; Supervision: EKWT; Writing–original draft: ASWM; Writing–review & editing: all authors. All authors read and approved the final manuscript.

Fig. 1.

Flowchart of the patient selection and 1:1 propensity score matching for patients with mid and low rectal cancer who underwent minimally invasive surgical resection between 2018 and 2023. BMI, body mass index; ASA, American Society of Anesthesiologists.

Fig. 2.

Comparison of mean index hospitalization costs between laparoscopic and robotic surgery for mid and low rectal cancer following propensity score matching (2018–2023). All monetary values are reported as means in Singapore dollars (SGD) at 2023 price levels (exchange rate, SGD 1=US $0.74). (A) Mid and low rectal cancer. (B) Low rectal cancer. (C) Mid rectal cancer.

Table 1.

Baseline demographic, clinical, and operative characteristics of patients with mid and low rectal cancer undergoing minimally invasive surgery (n=383)

Characteristic	Value
Sex
Male	243 (63.4)
Female	140 (36.6)
Age (yr)	64.3 (58.6–72.3)
Body mass index (kg/m²)	23.4 (21.0–26.1)
ASA physical status
I	7 (1.8)
II	270 (70.5)
III	106 (27.7)
Operative time (min)	347.1 (270–445)
Procedure type
Abdominoperineal resection	57 (14.9)
Low anterior resection	122 (31.9)
Ultralow anterior resection	198 (51.7)
Hartmann procedure	6 (1.6)
Surgical approach
Laparoscopic	201 (52.5)
Robotic	182 (47.5)
Defunctioning stoma
Yes	249 (65.0)
No	134 (35.0)
Postoperative length of stay (day)	6.3 (4–8)
Tumor location^a
Low rectum (<5 cm from AV)	173 (45.2)
Mid rectum (5–10 cm from AV)	210 (54.8)
Neoadjuvant therapy
Yes	132 (34.5)
No	251 (65.5)
Lymph node yield	17.9 (14–23)
Clear radial margin	367 (95.8)
Radial margin distance (mm)	1.15 (0.7–2.4)
Clear distal margin	371 (96.9)
Distal margin distance (cm)	1.6 (1–3)
Completeness of TME^b
Complete	326 (85.1)
Near complete	47 (12.3)
Incomplete	10 (2.6)
Conversion to open surgery	9 (2.3)
Postoperative complication (Clavien-Dindo classification)
Grade I	62 (16.2)
Grade II	20 (5.2)
Grade III	11 (2.9)
Grade IV	1 (0.3)
Grade V	1 (0.3)
Anastomotic leak^c	10 (2.6)
30-Day mortality	1 (0.3)
30-Day readmission	72 (18.8)

Values are presented as number (%) or median (interquartile range).

ASA, American Society of Anesthesiologists; AV, anal verge; TME, total mesorectal excision

^aDetermined by preoperative magnetic resonance imaging.

^bQuirke grading was used for macroscopic assessment of TME quality.

^cDefined as a clinically suspected leak confirmed by radiologic imaging and/or reoperation.

Table 2.

Baseline characteristics before and after propensity score matching between laparoscopic and robotic approaches for mid and low rectal cancer

Characteristic	Before propensity score matching (n=383)				After propensity score matching (n=282)
Characteristic	Laparoscopic group (n=201)	Robotic group (n=182)	P-value	SMD	Laparoscopic group (n=141)	Robotic group (n=141)	P-value	SMD
Sex			0.200	0.142			0.805	0.044
Male	121 (60.2)	122 (67.0)			87 (61.7)	90 (63.8)
Female	80 (39.8)	60 (33.0)			54 (38.3)	51 (36.2)
Age (yr)	66.6 (60.0–73.3)	65.0 (58.1–71.3)	0.103	0.191	65.9 (56.7–72.4)	65.0 (58.4–71.7)	0.602	0.045
Defunctioning stoma			0.005	0.304
Yes	117 (58.2)	132 (72.5)			94 (66.7)	97 (68.8)	0.799	0.046
No	84 (41.8)	50 (27.5)			47 (33.3)	44 (31.2)
Body mass index (kg/m²)	23.3 (21.0–26.4)	23.6 (20.9–25.7)	0.614	0.080	23.0 (20.9–25.8)	23.7 (21.1–25.9)	0.358	0.072
ASA physical status			0.844	0.059			0.707	0.099
I	3 (1.5)	4 (2.2)			3 (2.1)	2 (1.4)
II	141 (70.1)	129 (70.9)			95 (67.4)	101 (71.6)
III	57 (28.4)	49 (26.9)			43 (30.5)	38 (27.0)
Tumor location			0.012	0.271			0.904	0.029
Low rectum (<5 cm from AV)	78 (38.8)	95 (52.2)			61 (43.3)	59 (41.8)
Mid rectum (5–10 cm from AV)	123 (61.2)	87 (47.8)			80 (56.7)	82 (58.2)
Neoadjuvant therapy			0.035	0.227			0.901	0.030
Yes	59 (29.4)	73 (40.1)			52 (36.9)	50 (35.5)
No	142 (70.6)	109 (59.9)			89 (63.1)	91 (64.5)

Values are presented as number (%) or median (interquartile range). One-to-one nearest-neighbor propensity score matching was performed using a caliper width of 0.05. An SMD <0.10 was considered indicative of adequate covariate balance after matching for matching variables reported at the variable level. Category-level SMDs may exceed 0.10 despite acceptable balance in the corresponding overall variable.

SMD, standardized mean difference; ASA, American Society of Anesthesiologists; AV, anal verge.

Table 3.

Short-term clinical and histopathological outcomes after propensity score matching between laparoscopic and robotic approaches for mid and low rectal cancer (n=282)

Outcome	Laparoscopic group (n=141)	Robotic group (n=141)	P-value
Operative time (min)	325 (256–400)	368 (300–465)	0.007
Postoperative length of stay (day)	6.0 (5–8)	6.0 (4–7)	0.255
Lymph node yield	18.1 (14–23)	17.5 (14–22)	0.196
Clear radial margin	135 (95.7)	134 (95.0)	0.776
Radial margin distance (mm)	1.2 (0.7–2.2)	1.1 (0.8–2.5)	0.603
Clear distal margin	140 (99.3)	138 (97.9)	0.313
Distal margin distance (cm)	1.5 (1.0–2.8)	1.6 (1.0–3.0)	0.674
Completeness of TME^a			0.175
Complete	115 (81.6)	125 (88.7)
Near complete	20 (14.2)	14 (9.9)
Incomplete	6 (4.3)	2 (1.4)
Conversion to open surgery	6 (4.3)	2 (1.4)	0.151
Anastomotic leak	4 (2.8)	4 (2.8)	>0.999
30-Day mortality	1 (0.7)	0 (0)	-
30-Day readmission	21 (14.9)	33 (23.4)	0.069

Values are presented as median (interquartile range) or number (%).

TME, total mesorectal excision.

^aQuirke grading was used for macroscopic assessment of TME quality.

Table 4.

Reasons for 30-day readmission after minimally invasive rectal cancer surgery (n=54)

Reason for readmission	No. of patients (%)		P-value
Reason for readmission	Laparoscopic group (n=21)	Robotic group (n=33)
Surgery-related	13 (61.9)	31 (93.9)	0.009
Stoma-related complication	11 (52.4)	14 (42.4)	0.579
High stoma output	11 (52.4)	13 (39.4)	0.407
Peristomal bleeding	0 (0)	1 (3.0)	>0.999
Adhesive small bowel obstruction	1 (4.8)	10 (30.3)	0.036
Superficial SSI	1 (4.8)	2 (6.1)	>0.999
Intra-abdominal collection	0 (0)	3 (9.1)	0.274
Anastomotic leak	0 (0)	2 (6.1)	0.516
Medical complication	8 (38.1)	2 (6.1)	0.009

Reasons for readmission were categorized based on the primary documented diagnosis at the time of readmission and grouped as surgery-related or medical complications. Each readmission was assigned a single primary reason for tabulation. P-values were calculated using the Fisher exact test due to small cell counts.

SSI, surgical site infection.

Table 5.

Index hospitalization cost comparison between laparoscopic and robotic approaches for minimally invasive surgery in mid and low rectal cancer after propensity score matching

Cost component	Laparoscopic group	Robotic group	P-value
Overall cohort	141	141
Total index hospitalization cost (SGD)	31,724	37,436	0.008
Operative cost (SGD)	13,114	17,998	<0.001
Inpatient ward cost (SGD)	4,146	4,262	0.857
Inpatient treatment cost (SGD)	14,464	15,176	0.608
30-Day readmission cost (SGD)^a	8,048	17,636	0.079
Mid rectal cancer subgroup	80	82
Total index hospitalization cost (SGD)	30,186	38,792	0.008
Operative cost (SGD)	12,633	17,970	<0.001
Inpatient ward cost (SGD)	3,643	4,715	0.264
Inpatient treatment cost (SGD)	13,910	16,107	0.302
30-Day readmission cost (SGD)^a	9,575	17,861	0.234
Low rectal cancer subgroup	61	59
Total index hospitalization cost (SGD)	33,743	35,553	0.465
Operative cost (SGD)	13,745	18,038	<0.001
Inpatient ward cost (SGD)	4,807	3,633	0.135
Inpatient treatment cost (SGD)	15,191	13,882	0.397
30-Day readmission cost (SGD)^a	5,757	17,397	0.205

Values are presented as number of patients or mean costs in Singapore dollars (SGD) at 2023 price levels (exchange rate, SGD 1=US $0.74). Index hospitalization costs reflect the index surgical admission only and exclude costs incurred during readmission. Operative (surgical) costs include operating room utilization and consumables. Inpatient treatment costs include investigations and allied health services. Thirty-day readmission costs are reported separately as cumulative inpatient charges within 30 days of index discharge. All costs were calculated prior to government subsidies or insurance coverage and do not reflect out-of-pocket patient expenditures. Outpatient costs were excluded. P-values represent between-group comparisons within each cohort or subgroup.

^aSeparate from index admission.

REFERENCES

1. Siegel RL, Wagle NS, Cercek A, Smith RA, Jemal A. Colorectal cancer statistics, 2023. CA Cancer J Clin 2023;73:233–54. Article PubMed PDF
2. You YN, Hardiman KM, Bafford A, Poylin V, Francone TD, Davis K, et al. The American Society of Colon and Rectal Surgeons clinical practice guidelines for the management of rectal cancer. Dis Colon Rectum 2020;63:1191–222. Article PubMed
3. Rogers P, Dourado J, Emile SH, Wignakumar A, Delgado Z, Aeschbacher P, et al. Association between mesorectal grade and oncologic outcomes in rectal cancer: a systematic review and meta-analysis. J Surg Oncol 2025;132:437–46. Article PubMed PMC
4. Ma L, Yu HJ, Zhu YB, Li WX, Xu KY, Zhao AM, et al. Laparoscopy is non-inferior to open surgery for rectal cancer: a systematic review and meta-analysis. Cancer Med 2024;13:e7363. Article PubMed PMC
5. Kong M, Chen H, Shan K, Sheng H, Li L. Comparison of survival among adults with rectal cancer who have undergone laparoscopic vs open surgery: a meta-analysis. JAMA Netw Open 2022;5:e2210861. Article PubMed PMC
6. Martínez-Pérez A, Carra MC, Brunetti F, de'Angelis N. Pathologic outcomes of laparoscopic vs open mesorectal excision for rectal cancer: a systematic review and meta-analysis. JAMA Surg 2017;152:e165665. Article PubMed
7. Prete FP, Pezzolla A, Prete F, Testini M, Marzaioli R, Patriti A, et al. Robotic versus laparoscopic minimally invasive surgery for rectal cancer: a systematic review and meta-analysis of randomized controlled trials. Ann Surg 2018;267:1034–46. Article PubMed
8. Cheng CL, Rezac C. The role of robotics in colorectal surgery. BMJ 2018;360:j5304.Article PubMed
9. Jayne D, Pigazzi A, Marshall H, Croft J, Corrigan N, Copeland J, et al. Effect of robotic-assisted vs conventional laparoscopic surgery on risk of conversion to open laparotomy among patients undergoing resection for rectal cancer: the ROLARR randomized clinical trial. JAMA 2017;318:1569–80. Article PubMed PMC
10. Filho MO, Lenzi MC, de Lima PE, Amaral MA, Avelino PA, Almeida PL, et al. Redefining precision: a systematic review and meta-analysis of randomized controlled trials comparing robotic-assisted versus laparoscopic surgery in colorectal cancer. J Surg Oncol 2025;132:1224–34. Article PubMed
11. Mirza W, Dadan S, Khan HM, Yasmin S. Robotic versus laparoscopic surgery for rectal cancer: a systematic review and meta-analysis of randomized trials evaluating functional recovery, complication risk, and oncologic quality. J Robot Surg 2025;19:457.Article PubMed PDF
12. Chok AY, Zhao Y, Tan IE, Au MK, Tan EJ. Cost-effectiveness comparison of minimally invasive, robotic and open approaches in colorectal surgery: a systematic review and Bayesian network meta-analysis of randomized clinical trials. Int J Colorectal Dis 2023;38:86.Article PubMed PDF
13. Feng Q, Yuan W, Li T, Tang B, Jia B, Zhou Y, et al. Robotic versus laparoscopic surgery for middle and low rectal cancer (REAL): short-term outcomes of a multicentre randomised controlled trial. Lancet Gastroenterol Hepatol 2022;7:991–1004. Article PubMed
14. Gustafsson UO, Rockall TA, Wexner S, How KY, Emile S, Marchuk A, et al. Guidelines for perioperative care in elective colorectal surgery: Enhanced Recovery After Surgery (ERAS) Society recommendations 2025. Surgery 2025;184:109397.Article PubMed
15. Nagtegaal ID, van de Velde CJ, van der Worp E, Kapiteijn E, Quirke P, van Krieken JH, et al. Macroscopic evaluation of rectal cancer resection specimen: clinical significance of the pathologist in quality control. J Clin Oncol 2002;20:1729–34. Article PubMed
16. Safiejko K, Tarkowski R, Koselak M, Juchimiuk M, Tarasik A, Pruc M, et al. Robotic-assisted vs standard laparoscopic surgery for rectal cancer resection: a systematic review and meta-analysis of 19,731 patients. Cancers (Basel) 2021;14:180.Article PubMed PMC
17. Vogel I, Shinkwin M, van der Storm SL, Torkington J, A Cornish J, Tanis PJ, et al. Overall readmissions and readmissions related to dehydration after creation of an ileostomy: a systematic review and meta-analysis. Tech Coloproctol 2022;26:333–49. Article PubMed PMC PDF
18. Seow-En I, Wu J, Tan IE, Zhao Y, Seah AW, Wee IJ, et al. Transanal total mesorectal excision with delayed coloanal anastomosis versus laparoscopic and robotic total mesorectal excision for low rectal cancer: a propensity score–matched analysis of short-term outcomes, bowel function, and cost. Surg Laparosc Endosc Percutan Tech 2024;34:54–61. Article PubMed PMC

Figure & Data

References

Citations

Citations to this article as recorded by

Comment On: “Robotic versus laparoscopic surgery for mid and low rectal cancer: a propensity score–matched analysis of short-term outcomes and costs”
Zhibin Liu, Linfeng Liu, Xueqing Yao
Updates in Surgery.2026;[Epub] CrossRef

Cite this Article

Cite this Article: export Copy Download Format; Close

Download Citation

Download a citation file in RIS format that can be imported by all major citation management software, including EndNote, ProCite, RefWorks, and Reference Manager.

Format:

RIS — For EndNote, ProCite, RefWorks, and most other reference management software
BibTeX — For JabRef, BibDesk, and other BibTeX-specific software

Include:

Citation for the content below
Citation and abstract for the content below

Robotic versus laparoscopic surgery for mid and low rectal cancer: a propensity score–matched analysis of short-term outcomes and costs

Ann Coloproctol. 2026;42(3):355-363. Published online June 16, 2026

DOI: https://doi.org/10.3393/ac.2025.01508.0215

XML Download

Figure

Related articles

Robotic versus laparoscopic surgery for mid and low rectal cancer: a propensity score–matched analysis of short-term outcomes and costs

Fig. 1. Flowchart of the patient selection and 1:1 propensity score matching for patients with mid and low rectal cancer who underwent minimally invasive surgical resection between 2018 and 2023. BMI, body mass index; ASA, American Society of Anesthesiologists.

Fig. 2. Comparison of mean index hospitalization costs between laparoscopic and robotic surgery for mid and low rectal cancer following propensity score matching (2018–2023). All monetary values are reported as means in Singapore dollars (SGD) at 2023 price levels (exchange rate, SGD 1=US $0.74). (A) Mid and low rectal cancer. (B) Low rectal cancer. (C) Mid rectal cancer.

Fig. 1.

Fig. 2.

Robotic versus laparoscopic surgery for mid and low rectal cancer: a propensity score–matched analysis of short-term outcomes and costs

Characteristic	Value
Sex
Male	243 (63.4)
Female	140 (36.6)
Age (yr)	64.3 (58.6–72.3)
Body mass index (kg/m²)	23.4 (21.0–26.1)
ASA physical status
I	7 (1.8)
II	270 (70.5)
III	106 (27.7)
Operative time (min)	347.1 (270–445)
Procedure type
Abdominoperineal resection	57 (14.9)
Low anterior resection	122 (31.9)
Ultralow anterior resection	198 (51.7)
Hartmann procedure	6 (1.6)
Surgical approach
Laparoscopic	201 (52.5)
Robotic	182 (47.5)
Defunctioning stoma
Yes	249 (65.0)
No	134 (35.0)
Postoperative length of stay (day)	6.3 (4–8)
Tumor location^a
Low rectum (<5 cm from AV)	173 (45.2)
Mid rectum (5–10 cm from AV)	210 (54.8)
Neoadjuvant therapy
Yes	132 (34.5)
No	251 (65.5)
Lymph node yield	17.9 (14–23)
Clear radial margin	367 (95.8)
Radial margin distance (mm)	1.15 (0.7–2.4)
Clear distal margin	371 (96.9)
Distal margin distance (cm)	1.6 (1–3)
Completeness of TME^b
Complete	326 (85.1)
Near complete	47 (12.3)
Incomplete	10 (2.6)
Conversion to open surgery	9 (2.3)
Postoperative complication (Clavien-Dindo classification)
Grade I	62 (16.2)
Grade II	20 (5.2)
Grade III	11 (2.9)
Grade IV	1 (0.3)
Grade V	1 (0.3)
Anastomotic leak^c	10 (2.6)
30-Day mortality	1 (0.3)
30-Day readmission	72 (18.8)

Characteristic	Before propensity score matching (n=383)				After propensity score matching (n=282)
Characteristic	Laparoscopic group (n=201)	Robotic group (n=182)	P-value	SMD	Laparoscopic group (n=141)	Robotic group (n=141)	P-value	SMD
Sex			0.200	0.142			0.805	0.044
Male	121 (60.2)	122 (67.0)			87 (61.7)	90 (63.8)
Female	80 (39.8)	60 (33.0)			54 (38.3)	51 (36.2)
Age (yr)	66.6 (60.0–73.3)	65.0 (58.1–71.3)	0.103	0.191	65.9 (56.7–72.4)	65.0 (58.4–71.7)	0.602	0.045
Defunctioning stoma			0.005	0.304
Yes	117 (58.2)	132 (72.5)			94 (66.7)	97 (68.8)	0.799	0.046
No	84 (41.8)	50 (27.5)			47 (33.3)	44 (31.2)
Body mass index (kg/m²)	23.3 (21.0–26.4)	23.6 (20.9–25.7)	0.614	0.080	23.0 (20.9–25.8)	23.7 (21.1–25.9)	0.358	0.072
ASA physical status			0.844	0.059			0.707	0.099
I	3 (1.5)	4 (2.2)			3 (2.1)	2 (1.4)
II	141 (70.1)	129 (70.9)			95 (67.4)	101 (71.6)
III	57 (28.4)	49 (26.9)			43 (30.5)	38 (27.0)
Tumor location			0.012	0.271			0.904	0.029
Low rectum (<5 cm from AV)	78 (38.8)	95 (52.2)			61 (43.3)	59 (41.8)
Mid rectum (5–10 cm from AV)	123 (61.2)	87 (47.8)			80 (56.7)	82 (58.2)
Neoadjuvant therapy			0.035	0.227			0.901	0.030
Yes	59 (29.4)	73 (40.1)			52 (36.9)	50 (35.5)
No	142 (70.6)	109 (59.9)			89 (63.1)	91 (64.5)

Outcome	Laparoscopic group (n=141)	Robotic group (n=141)	P-value
Operative time (min)	325 (256–400)	368 (300–465)	0.007
Postoperative length of stay (day)	6.0 (5–8)	6.0 (4–7)	0.255
Lymph node yield	18.1 (14–23)	17.5 (14–22)	0.196
Clear radial margin	135 (95.7)	134 (95.0)	0.776
Radial margin distance (mm)	1.2 (0.7–2.2)	1.1 (0.8–2.5)	0.603
Clear distal margin	140 (99.3)	138 (97.9)	0.313
Distal margin distance (cm)	1.5 (1.0–2.8)	1.6 (1.0–3.0)	0.674
Completeness of TME^a			0.175
Complete	115 (81.6)	125 (88.7)
Near complete	20 (14.2)	14 (9.9)
Incomplete	6 (4.3)	2 (1.4)
Conversion to open surgery	6 (4.3)	2 (1.4)	0.151
Anastomotic leak	4 (2.8)	4 (2.8)	>0.999
30-Day mortality	1 (0.7)	0 (0)	-
30-Day readmission	21 (14.9)	33 (23.4)	0.069

Reason for readmission	No. of patients (%)		P-value
Reason for readmission	Laparoscopic group (n=21)	Robotic group (n=33)
Surgery-related	13 (61.9)	31 (93.9)	0.009
Stoma-related complication	11 (52.4)	14 (42.4)	0.579
High stoma output	11 (52.4)	13 (39.4)	0.407
Peristomal bleeding	0 (0)	1 (3.0)	>0.999
Adhesive small bowel obstruction	1 (4.8)	10 (30.3)	0.036
Superficial SSI	1 (4.8)	2 (6.1)	>0.999
Intra-abdominal collection	0 (0)	3 (9.1)	0.274
Anastomotic leak	0 (0)	2 (6.1)	0.516
Medical complication	8 (38.1)	2 (6.1)	0.009

Cost component	Laparoscopic group	Robotic group	P-value
Overall cohort	141	141
Total index hospitalization cost (SGD)	31,724	37,436	0.008
Operative cost (SGD)	13,114	17,998	<0.001
Inpatient ward cost (SGD)	4,146	4,262	0.857
Inpatient treatment cost (SGD)	14,464	15,176	0.608
30-Day readmission cost (SGD)^a	8,048	17,636	0.079
Mid rectal cancer subgroup	80	82
Total index hospitalization cost (SGD)	30,186	38,792	0.008
Operative cost (SGD)	12,633	17,970	<0.001
Inpatient ward cost (SGD)	3,643	4,715	0.264
Inpatient treatment cost (SGD)	13,910	16,107	0.302
30-Day readmission cost (SGD)^a	9,575	17,861	0.234
Low rectal cancer subgroup	61	59
Total index hospitalization cost (SGD)	33,743	35,553	0.465
Operative cost (SGD)	13,745	18,038	<0.001
Inpatient ward cost (SGD)	4,807	3,633	0.135
Inpatient treatment cost (SGD)	15,191	13,882	0.397
30-Day readmission cost (SGD)^a	5,757	17,397	0.205

Table 1. Baseline demographic, clinical, and operative characteristics of patients with mid and low rectal cancer undergoing minimally invasive surgery (n=383)

Values are presented as number (%) or median (interquartile range).

ASA, American Society of Anesthesiologists; AV, anal verge; TME, total mesorectal excision

Determined by preoperative magnetic resonance imaging.

Quirke grading was used for macroscopic assessment of TME quality.

Defined as a clinically suspected leak confirmed by radiologic imaging and/or reoperation.

Table 2. Baseline characteristics before and after propensity score matching between laparoscopic and robotic approaches for mid and low rectal cancer

SMD, standardized mean difference; ASA, American Society of Anesthesiologists; AV, anal verge.

Table 3. Short-term clinical and histopathological outcomes after propensity score matching between laparoscopic and robotic approaches for mid and low rectal cancer (n=282)

Values are presented as median (interquartile range) or number (%).

TME, total mesorectal excision.

Quirke grading was used for macroscopic assessment of TME quality.

Table 4. Reasons for 30-day readmission after minimally invasive rectal cancer surgery (n=54)

SSI, surgical site infection.

Table 5. Index hospitalization cost comparison between laparoscopic and robotic approaches for minimally invasive surgery in mid and low rectal cancer after propensity score matching