Oncological outcome of carcinomas in the rectosigmoid junction compared to the upper rectum or sigmoid colon - A retrospective cohort study

Abstract

Introduction: Although carcinomas of the rectosigmoid junction are frequent, specific data on these tumors are sparse because assignment either to the colon or rectum is common. The objective of this study is to determine whether carcinomas of the rectosigmoid junction can be assigned to the sigmoid colon or to the upper rectum in terms of tumor characteristics and oncological outcome.

Materials and methods: 337 consecutive patients undergoing resection of carcinomas in the sigmoid colon, the rectosigmoid junction and the upper third of the rectum were analyzed retrospectively and additionally followed-up for oncological outcome.

Results: 185 patients (54.9%) showed carcinoma in the sigmoid colon, 41 (12.2%) in the rectosigmoid junction and 111 (32.9%) in the upper rectum. Synchronous liver metastases (rectosigmoid junction 31.7%, sigmoid colon 16.2%, upper rectum 11.7%; P = 0.01), lymphovascular invasion (rectosigmoid junction 46.3%, sigmoid colon 25.4%, upper rectum 32.4%; P = 0.03) and pN2 (rectosigmoid junction 31.7%, sigmoid colon 10.3%, upper rectum 13.5%; P = 0.002) were more common in carcinomas of the rectosigmoid junction. The median follow-up period was 44 (22-75.5) months. Five-year overall survival was 44.6% in patients with carcinomas in the rectosigmoid junction, 70.9% in the sigmoid colon, and 70.2% in the upper rectum.

Conclusion: Carcinomas of the rectosigmoid junction reveal a deviant behavioral pattern compared to its adjacent bowel segments.

Keywords: Colon cancer; Colorectal carcinoma; Colorectal surgery; Liver metastasis; Rectal cancer; Rectosigmoid junction.