High incidence of urinary bladder involvement in carcinomas of the sigmoid and rectum: a retrospective review of 580 patients with colorectal carcinoma.

BACKGROUND AND OBJECTIVES: It is not uncommon for colorectal carcinomas to invade the urinary bladder. However, the actual incidence of urinary bladder invasion of colorectal carcinomas and the common sites of the original tumors are still unclear.
METHODS: The clinical records of 580 patients diagnosed with colorectal carcinoma were retrospectively reviewed. A further review of patients with urinary bladder invasion was performed.
RESULTS: Of the 580 patients, 17 (2.9%) had a diagnosis of urinary bladder invasion intraoperatively. The incidence of bladder involvement was significantly higher in carcinomas of the sigmoid and rectum than in carcinomas of other colon segments (4.1 vs. 0.5%, P = 0.017). Although a combination of computed tomography (CT) and cystoscopy predicted 80% of the bladder involvement, preoperative diagnostic modalities could not provide information for the differentiation between macroscopic and pathological invasion or the necessity for total cystectomy.
CONCLUSIONS: The sigmoid colon and rectum were common sites of the original tumors invading the urinary bladder compared with other colon segments. CT and cystoscopy are recommended for preoperative screening of the bladder involvement of sigmoid colon and rectal cancer. However, it appeared to be difficult to predict the pathological invasion of malignant cells and the necessity for total cystectomy preoperatively.