Comparison of survival and recurrence between colonic and rectal tumors after resection in T1 colorectal cancer: long-term cohort study.

BACKGROUND AND AIMS: Lesion location's impact on recurrence after T1 colorectal cancer (CRC) resection remains unclear. This study evaluated survival and recurrence differences between colonic and rectal tumors after T1 CRC resection.

METHODS

Patients who underwent T1 CRC resection were reviewed on the basis of pathologic risk factors for lymph node metastases according to the Japanese Society for Cancer of the Colon and Rectum guidelines. Participants were divided into low-risk (group A), high-risk after endoscopic resection (ER) only (group B), and high-risk after surgical resection (SR) or ER and SR (group C) groups. Survival and recurrence rates were compared between colonic and rectal tumors.

RESULTS

In 987 patients (median follow-up: 60 months), there were no significant differences in the disease-specific survival rate (A: 99.2% vs 100%, P = .582; B: 96.6% vs 100%, P = .577) or cumulative recurrence (A: 2.3% vs 0%, P = .523; B: 3.0% vs 0%, P = .399) between colonic and rectal tumors, respectively, in groups A and B. In group C, rectal lesions showed significantly higher cumulative recurrence (4.8% vs 1.1%, P = .002) and lower disease-specific survival rates (98.2% vs 99.8%, P = .024) than colonic lesions. Rectal tumor location (hazard ratio [HR], 3.25), venous invasion (HR, 9.40), and high budding grade (HR, 3.05) were independent recurrence risk factors in group C.

CONCLUSIONS

T1 rectal cancer had a worse prognosis than T1 colonic cancer after high-risk lesion SR. Careful surveillance is required for high-risk T1 rectal cancers with venous invasion or a high budding grade.