Carcinoma arising from Crohn disease (CD) is rare, and there is no clear guidance on how to properly screen for at-risk patients and choose appropriate care. This study aimed to evaluate the clinicopathological characteristics, treatment, and oncologic outcomes of CD patients diagnosed with colorectal cancer (CRC).
Using medical records, we retrospectively enrolled a single-center cohort of 823 patients who underwent abdominal surgery for CD between January 2006 and December 2015. CD-associated CRC patients included those with adenocarcinoma, lymphoma, or neuroendocrine tumors of the colon and rectum.
Nineteen patients (2.3%) underwent abdominal surgery to treat CD-associated CRC. The mean duration of CD in the CD-associated CRC group was significantly longer than that in the benign CD group (124.7±77.7 months vs. 68.9±60.2 months, P = 0.006). The CD-associated CRC group included a higher proportion of patients with a history of perianal disease (73.7% vs. 50.2%, P = 0.035) and colonic location (47.4% vs. 6.5%, P = 0.001). Among 19 CD-associated CRC patients, 17 (89.5%) were diagnosed with adenocarcinoma, and of the 17 cases, 15 (88.2%) were rectal adenocarcinoma. On multivariable analyses for developing CRC, only colonic location was a risk factor (relative risk, 7.735; 95% confidence interval, 2.862–20.903; P = 0.001).
Colorectal malignancy is rare among CD patients, even among patients who undergo abdominal surgery. Rectal adenocarcinoma accounted for most of the CRC, and colonic location was a risk factor for developing CRC.
Crohn disease (CD) is a major form of inflammatory bowel disease (IBD) that can affect any site along the gastrointestinal tract and often necessitates surgical treatment [
The incidence of malignancy associated with CD is quite low, reportedly ranging between 0.3% and 0.8% [
CRCs associated with perianal fistulas are relatively rare, and they tend to occur in patients who have had perianal fistulas for more than 10 years. Abdominoperineal resection (APR) is generally considered to be the surgical treatment of choice for carcinoma associated with perianal fistula. There are few articles with small series that describe sporadic cases of perianal cancer associated with CD fistulas [
This study aimed to evaluate the clinicopathological characteristics as well as the surgical and oncologic outcomes of patients with CD-associated CRC.
We retrospectively reviewed the medical records of 823 patients who underwent abdominal surgery for CD at Asan Medical Center, Seoul, Korea, between January 2006 and December 2015. Patients were included if they had undergone bowel resection, strictureplasty, stoma formation, or bypass surgery for CD during the study period and were 16 years of age or older at the time of surgery. Patients who underwent only stoma restoration were excluded.
CD-associated CRC was defined as malignancy of the colon and rectum that occurred in patients who were diagnosed with CD and had started medication to treat CD. The study included patients with colorectal adenocarcinoma, lymphoma, and neuroendocrine tumors. We excluded patients who were diagnosed with squamous cell carcinoma originating from the anus, cervical cancer, low-grade dysplasia, and metastatic carcinoma.
The following variables were captured during data collection: demographic and general information (age at diagnosis and operation; sex; duration of disease [duration between CD diagnosis and the last follow-up]; follow-up period; family history of CD; and history of smoking, perianal disease, abdominal surgery, or perianal surgery), clinical characteristics (Montreal classification and preoperative medications), operative findings (emergency operation, surgical approach, stoma formation, and operation time), operative outcomes (postoperative complications and hospital stay), histopathologic findings (tumor type, differentiation, anatomic association between perianal fistula and tumor, and stage), neoadjuvant or adjuvant treatment (chemotherapy or chemoradiotherapy [CRT]), and survival outcome.
Investigations for diagnosing and monitoring CD included small bowel series, computed tomography (CT) enterography, magnetic resonance imaging (MRI), and colonoscopy. Through these tests, the locations affected by CD could be confirmed, pathological features were evaluated, and, if necessary, surgical findings and postoperative histopathological findings were used for diagnosis [
When treating CD patients, a step-up approach is generally used in our institution, which means adding more potent therapies when the first-line or less toxic agents are not effective [
The follow-up schedule for CRC usually proceeded as follows: clinical examinations, laboratory tests including carcinoembryonic agent, abdominopelvic CT every 6 months for the first 3 postoperative years, chest CT every 12 months, and colonoscopy or sigmoidoscopy after 1 postoperative year and then 2 or 3 years later. Patients suspected of recurrence underwent specific examinations (MRI, or positron emission tomography [PET]). Recurrence was diagnosed by radiological and histopathological methods using surgical resection or biopsy specimens [
Discrete variables, including demographic and preoperative characteristics, operative methods, and operative details were analyzed using the chi-square test to compare the CD-associated CRC group with the benign CD group. Continuous variables including, age at surgery, hospital stay, disease duration, and follow-up duration, were compared using unpaired Student t-test or the Mann-Whitney U-test as appropriate. The overall survival rate was examined using the Kaplan-Meier method and compared using the log-rank test. Multivariable analyses using binary logistic regression were used to assess the risks of developing CRC. Statistical significance was defined as P < 0.05, and all statistical analyses were performed using IBM SPSS Statistics for Windows, ver. 21 (IBM Corp., Armonk, NY, USA).
The study protocol was approved by the Institutional Review Board of the Asan Medical Center (No. 2020-0328) with a waiver for informed consent, and the study was performed in accordance with the Declaration of Helsinki.
A total of 823 patients were finally included in this study. Nineteen patients (2.3%) underwent abdominal surgery for CD-associated CRC, and 804 patients (97.7%) underwent abdominal surgery for benign CD during the study period. The mean age at the time of surgery among patients in the CD-associated CRC group was significantly older than that among patients in benign group (39.2±11.3 years vs. 31.5±9.9 years, P= 0.002). The mean duration of CD in the CD-associated CRC group was significantly longer than that in the benign CD group (124.7±77.7 months vs. 68.9±60.2 months, P = 0.006). The CD-associated CRC group had significantly higher proportions of patients with a history of perianal disease (78.9% vs. 50.2%, P= 0.035) and abdominal surgery (57.9% vs. 33.8%, P= 0.001). Compared with the benign CD group, the CD-associated CRC group had a significantly higher proportion of patients with non-stricturing and non-penetrating (B1) CD (42.1% vs. 4.7%, P = 0.001), and a significantly lower proportion of patients with penetrating (B3) CD (26.3% vs. 60.6%, P= 0.001), according to the Montreal classification. At the time of surgery, the CD-associated CRC group had a significantly lower proportion of patients with ileal disease (5.3% vs. 42.5%, P= 0.001) and a significantly higher proportion of patients with colonic disease (47.4% vs. 6.5%, P= 0.001), compared with the benign CD group. Variables that did not differ significantly between these 2 groups included age at diagnosis, sex, follow-up duration, family history of CD, history of smoking, history of perianal surgery, age at diagnosis by the Montreal classification, and preoperative medications (
Of the 19 patients with CD-associated CRC, 16 (84.2%) underwent stoma formation procedures (including either permanent or diverting stomas), while 127 benign CD patients (15.8%) underwent stoma formation procedures (P= 0.001). The mean operating time among patients in the CD-associated CRC group was significantly longer than that among patients in the benign CD group (250±123 minutes vs. 158±61 minutes, P = 0.001). The rates of emergency operations, surgical approach, postoperative complications (including infectious and intra-abdominal complications), as well as the mean postoperative hospital stay duration were not significantly different between the 2 groups (
Within the CD-associated CRC group, 17 patients (89.5%) were diagnosed with adenocarcinoma, 1 patient (5.3%) was diagnosed with a neuroendocrine carcinoma and the other patient (5.3%) was diagnosed with plasmablastic lymphoma. Seven patients (36.8%) were already diagnosed with stage IV cancer at the time of diagnosis. Among the 17 patients with colorectal adenocarcinoma, 15 (88.2%) had rectal adenocarcinoma, and 2 (11.8%) had colonic adenocarcinoma (
At the time of diagnosis, 5 patients (26.3%) whose tumors were inoperable underwent only stoma formation without radical surgery. Eight patients (42.1%) underwent APR, 3 patients (17.6%) underwent total colectomy or total proctocolectomy (TPC) due to severe colitis, and 3 patients (17.6%) underwent segmental resection and anastomosis (right colectomy or low anterior resection). Although more than half of the cases were associated with unfavorable histology, 8 patients (42.1%) received preoperative or postoperative radiotherapy. A patient was finally diagnosed with pathologic complete remission (pCR) after receiving preoperative CRT, followed by APR (
The 5-year overall survival rates of the 17 patients with colorectal adenocarcinoma and 15 patients with rectal adenocarcinoma were 52.6%±11.5% and 53.3%±13.0%, respectively. One patient with stage IV neuroendocrine carcinoma died within 30 postoperative months, and 1 patient with stage I lymphoma was alive with recurrence after 51 months (
On additional multivariable analyses for developing CRC, only the L3 classification (CD colitis) was revealed as a risk factor of developing CRC (relative risk, 7.735; 95% confidence interval, 2.862–20.903; P= 0.001).
The present study showed a CD-associated CRC prevalence of 2.3% among patients who underwent abdominal surgery for CD. Unsurprisingly, this prevalence was higher than that of the general CD population, as the present study included patients who had abdominal surgery. Although there has been some controversy regarding the increased risk of developing cancer in association with CD since the first report of CD-associated CRC in 1948 [
The present study demonstrated the association between the anatomic location of the CD involvement and the development of CRC. The CD-associated CRC group had a significantly higher rate of perianal fistula history, and more than half of the CD-associated CRC had an anatomical association between perianal fistula and tumor. There have been some reports of fistula-associated CRC in CD patients, and those reports also suggested a possible association between perianal fistula and CRC [
Surgery for CD-associated CRC is complicated by the conflicting objectives of minimal bowel resection and appropriate tumor resection. For CD-associated CRC, American Society of Colon and Rectal Surgery clinical practice guidelines insist on TPC for multiplicity and to reduce the risk of metachronous CRC [
Although a high rate of stage IV CRC was observed in the present study, patients with early stage (pCR, stage I, and stage II) and favorable histology had a relatively good 5-year overall survival rate. This finding highlights the importance of early detection in terms of facilitating good oncologic outcomes. However, it is difficult to diagnose fistula-associated CRC because it is difficult to distinguish malignancy from CD colitis in perianal fistulas. In general, symptoms of CD-associated CRC are non-specific, and the sensitivity of the imaging test (CT, MRI, and PET) is relatively low owing to inflammation, and this can lead to delayed diagnosis [
The prognosis of CD-associated CRC patients after surgery is largely determined by the CRC stage after surgery [
Because the present study was retrospective and cross-sectional in design, we could not control for clinicopathological characteristics. However, the study evaluated both CD-associated CRC and benign CD characteristics, including demographics, surgical methods, pathologic findings, and postoperative and oncologic outcomes, using a relatively large patient cohort. Another limitation of this study was the lack of analysis of risk factors for developing CRC in association with CD due to the small number of CD-associated CRC patients. Nevertheless, the present study was meaningful, as it included a larger number of patients than other retrospective studies, and it clarified the prevalence of CD-associated CRC among patients who underwent abdominal surgery.
In conclusion, the diagnosis of colorectal malignancy is rare among CD patients who have undergone abdominal surgery and the L3 classification (CD colitis) was a risk factor of developing CRC. Rectal adenocarcinoma accounted for most of the CRC, and the subgroup with unfavorable histology had poor overall survival rate.
No potential conflict of interest relevant to this article was reported.
Supplementary materials for this study are presented online (available at
Supplementary Table 1. Clinicopathological characteristics and survival of the patients with Crohn disease (CD)-associated colorectal adenocarcinoma according to histologic type
Classification and survival outcomes of the patients with Crohn disease (CD)-associated colorectal cancer (CRC). NEC, neuroendocrine carcinoma; GI, gastrointestinal; NED, no evidence of disease; OS, overall survival.
Overall survival (OS) outcome according to tumor type (A) (Adeno., adenocarcinoma; NEC, neuroendocrine carcinoma; Lymphoma) and histologic type (B) (favorable, well-differentiated and moderately-differentiated; unfavorable, poorly-differentiated, mucinous, and signetring cell).
Clinical characteristics of the patients with CD-associated CRC and benign CD
Variable | CD-associated CRC | Benign CD | P-value |
---|---|---|---|
No. of patients | 19 | 804 | |
Age (yr) | |||
At diagnosis | 29.7 ± 10.2 (23–36) | 26.1 ± 10.0 (19–31) | 0.150 |
At operation | 39.2 ± 11.3 (32–49) | 31.5 ± 9.9 (24–37) | 0.009 |
Sex, female:male | 7 (36.8):12 (63.2) | 233 (29.0):571 (71.0) | 0.450 |
Duration of disease (mo) | 124.7 ± 77.7 (66–172) | 68.9 ± 60.2 (14–109) | 0.006 |
Follow-up period (mo) | 81.7 ± 39.1 (48–107) | 85.1 ± 39.1 (59–111) | 0.710 |
Family history of Crohn disease, yes | 0 (0) | 24 (3.0) | |
History of smoking | 0.630 | ||
None | 11 (57.9) | 528 (65.7) | |
Ex-smoker | 5 (26.3) | 199 (24.8) | |
Current smoker | 3 (15.8) | 77 (9.6) | |
History of perianal disease |
0.035 |
||
Yes | 15 (78.9) | 404 (50.2) | |
No | 4 (21.1) | 400 (49.8) | |
History of abdominal surgery | 0.001 |
||
Yes | 11 (57.9) | 272 (33.8) | |
No | 8 (42.1) | 532 (66.2) | |
History of perianal surgery | 0.960 | ||
Yes | 12 (63.2) | 332 (41.3) | |
No | 7 (36.1) | 471 (58.7) | |
Montreal classification | |||
Age at diagnosis (yr) | 0.990 | ||
≤ 16 | 2 (10.5) | 89 (11.1) | |
> 16, ≤ 40 | 15 (78.9) | 639 (79.4) | |
> 40 | 2 (10.5) | 76 (9.5) | |
Behavior at operation | 0.001 |
||
Non-stricturing, non-penetrating (B1) | 8 (42.1) | 38 (4.7) | |
Stricturing (B2) | 6 (31.6) | 279 (34.7) | |
Penetrating (B3) | 5 (26.3) | 487 (60.6) | |
Montreal classification location at operation | 0.001 |
||
Ileum (L1) | 1 (5.3) | 343 (42.7) | |
Colon (L2) | 9 (47.4) | 52 (6.5) | |
Ileocolon (L3) | 9 (47.4) | 408 (50.7) | |
Medication | |||
No medication or 5-ASA only | 5 (26.3) | 340 (42.5) | 0.239 |
Immunomodulator | 8 (42.1) | 253 (31.5) | 0.330 |
anti-TNF-α | 1 (5.3) | 48 (6.0) | 0.990 |
Steroid | 2 (10.5) | 41 (5.1) | 0.260 |
Immunomodulator with anti-TNF-α | 3 (15.8) | 57 (7.1) | 0.070 |
Immunomodulator with steroid | 0 (0) | 43 (5.3) | 0.618 |
Steroid with anti-TNF-α | 0 (0) | 8 (1.0) | 0.990 |
All combinations | 0 (0) | 12 (1.5) | 0.990 |
Values are presented as number only, mean±standard deviation (interquartile range), or number (%).
CD, Crohn disease; CRC, colorectal cancer; ASA, aminosalicylic acid; anti-TNF-α, anti-tumor necrosis factor α.
Including anal fistula and anal fissure.
P<0.05.
Operative finding and postoperative outcome of the patients with CD-associated CRC and benign CD
Variable | CD-associated CRC (n = 19) | Benign CD (n = 804) | P-value |
---|---|---|---|
Emergency operation | 1 (5.3) | 70 (8.7) | 0.990 |
Surgical approach | 0.780 | ||
Open | 16 (84.2) | 638 (79.4) | |
Laparoscopy | 3 (15.8) | 166 (20.6) | |
Stoma formation | 0.001 |
||
Yes | 16 (84.2) | 127 (15.8) | |
No | 3 (16.8) | 677 (84.2) | |
Operation time (min) | 250 ± 123 (177–286) | 158 ± 61 (113–187) | 0.001 |
Postoperative complication | 0.920 | ||
Yes | 6 (31.6) | 202 (25.1) | |
No | 13 (68.4) | 602 (74.9) | |
Infectious complication | 0.710 | ||
Yes | 5 (26.3) | 152 (18.9) | |
No | 14 (73.7) | 652 (81.1) | |
Intraabdominal complication | 0.650 | ||
Yes | 3 (15.8) | 77 (9.6) | |
No | 16 (84.2) | 727 (90.4) | |
Hospital stay after operation (day) | 16.5 ± 27.6 (5–21) | 13.1 ± 15.0 (7–13) | 0.340 |
Values are presented as number (%) or mean±standard deviation (interquartile range).
CD, Crohn disease; CRC, colorectal cancer.
P<0.05.
Clinicopathological characteristics and survival of the patients with CD-associated colorectal cancer
Characteristic | Adenocarcinoma | NEC | Lymphoma |
---|---|---|---|
No. of patients | 17 | 1 | 1 |
Sex, female:male | 7 (41.2):10 (58.8) | 0 (0):1 (100) | 0 (0):1 (100) |
Age (yr) | |||
At operation | 39.7 ± 10.3 (32–47) | 58 | 25 |
At diagnosis | 30.2 ± 9.9 (24–36) | 35 | 14 |
Location | |||
Colon | 2 (11.8) | - | - |
Rectum | 15 (88.2) | 1 (100) | 1 (100) |
History of perianal fistula | 13 (76.5) | 1 (100) | 1 (100) |
Smoking | |||
None | 10 (58.8) | - | 1 (100) |
Ex-smoker | 5 (29.4) | - | - |
Current | 2 (11.8) | 1 (100) | - |
Duration of disease (mo) | |||
≥ 5 yr | 15 (88.2) | 1 (100) | 0 (0) |
≥ 10 yr | 11 (64.7) | 1 (100) | 0 (0) |
Preoperarive CD medicaiton | |||
Anti-TNF-α only | 1 (5.9) | 0 (0) | 0 (0) |
Immunomodulator only | 7 (41.2) | 1 (100) | 0 (0) |
Combination | 3 (17.6) | 0 (0) | 1 (100) |
Tumor associated with perianal fistula | 10 (58.8) | 0 (0) | 0 (0) |
Differentiation or tumor type | Large cell type | Plasmabalstic | |
WD/MD | 6 (35.3) | ||
PD/mucinous/SRC | 11 (64.7) | ||
Operation name | |||
APR | 8 (47.1) | - | - |
TC or TPC with stomy | 3 (17.6) | - | - |
Stoma with biopsy | 3 (17.6) | 1 (100) | 1 (100) |
RHC/uLAR with CAA | 2 (11.8) | - | - |
Pathologic stage | |||
pCR | 1 (5.9) | - | - |
I | 3 (17.6) | - | 1 (100) |
II | 6 (35.3) | - | - |
III | 1 (5.9) | - | - |
IV | 6 (35.3) | 1 (100) | - |
Additional treatment | |||
None | 3 (17.6) | - | - |
Best supportive care | 1 (5.9) | - | - |
Neoadjuvant CCRT | 3 (17.6) | - | - |
Adjuvant CTx | 3 (17.6) | - | 1 (100) |
Adjuvant CCRT | 2 (11.8) | - | - |
Palliative CTx | 3 (17.6) | - | - |
Palliative CCRT | 2 (11.8) | 1 (100) | - |
Survival | |||
Yes | 8 (47.1) | - | 1 (100) |
No | 9 (52.9) | 1 (100) | - |
Values are presented as number only, number (%), or mean±standard deviation (interquartile range).
CD, Crohn disease; NEC, neuroendocrine carcinoma; anti-TNF-α, anti-tumor necrosis factor α; WD, well-differentiated; MD, moderately-differentiated; PD, poorly-differentiated; SRC, signet-ring cell carcinoma; APR, abdominoperineal resection; TC, total colectomy; TPC, total proctocolectomy; RHC, right hemicolectomy; uLAR, ultra-low anterior resection; CAA, coloanal anastomosis; pCR, pathologic complete remission; CCRT, chemoradiotherapy; CTx, chemotherapy.