Lymph-node metastasis is considered as critical prognostic factor in colorectal cancer. A preoperative evaluation of lymph-node metastasis can also help to determine the range of distant lymph node dissection. However, the reliability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the detection of lymph-node metastasis is not fully known.
The medical records of 433 patients diagnosed with colorectal cancer were reviewed retrospectively. FDG-PET/CT and CT were performed on all patients. Lymph nodes were classified into regional and distant lymph nodes according to the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, 7th edition.
The patients included 231 males (53.3%) and 202 females (46.7%), with a mean age of 64.7 ± 19.0 years. For regional lymph nodes, the sensitivity of FDG-PET/CT was lower than that of CT (57.1% vs. 73.5%, P < 0.001). For distant lymph nodes, the sensitivity of FDG-PET/CT was higher than that of CT (64.7% vs. 52.9%, P = 0.012). The sensitivity of FDG-PET/CT for regional lymph nodes was higher in patients with larger primary tumors. The positivity of lymph-node metastasis for FDG-PET/CT was affected by carcinoembryonic antigen levels, tumor location, and cancer stage for regional lymph nodes and by age and cancer stage for distant lymph nodes (P < 0.05).
The sensitivity of FDG-PET/CT for regional lymph-node metastasis was not superior to that of CT. However, FDG-PET/CT provides helpful information for determining surgical plan especially in high risk patients group.
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Adjuvant chemotherapy is routinely recommended for locally advanced colorectal cancer (CRC). There are very few data for the optimal starting date of adjuvant chemotherapy after the surgery. This study aimed to evaluate the effectiveness of earlier adoption of adjuvant chemotherapy after curative surgery for stage III CRC.
In this study, 159 patients with stage III CRC, who had undergone a curative resection, were enrolled retrospectively. Patients were categorized into 3 groups representing different timings to initiate the chemotherapy; less than 2 weeks (group 1), 3 to 4 weeks (group 2), and more than 5 weeks (group 3). The overall survival rate (OS) and the relapse-free survival rate (RFS) were analyzed to evaluate the effectiveness of adjuvant chemotherapy.
The 5-year OSs of the patients were 73.7% in group 1, 67.0% in group 2, and 55.2% in group 3. The 5-year RFSs of the patients were 48.8% in group 1, 64.7% in group 2, and 57.1% in group 3. There were no significant differences in either the OS or the RFS (P = 0.200, P = 0.405).
Starting chemotherapy earlier than 6 weeks after surgery does not show any significant difference. Thus, although adjuvant chemotherapy should preferably begin within 6 weeks, the starting date should not necessarily be hastened, and the patient's general condition should be taken into consideration.
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