Intestinal metaplasia is not a strong risk factor for bladder cancer: study of 53 cases with long-term follow-up.

OBJECTIVES

Intestinal metaplasia often coexists with adenocarcinoma of the urinary bladder, suggesting to some investigators that it is premalignant. However, the natural history and long-term outcome of intestinal metaplasia in isolation are unknown. We report 53 cases of intestinal metaplasia of the urinary bladder followed for more than 10 years.

METHODS

We reviewed the Mayo Clinic surgical pathology files between 1926 and 1996 and all patients with exstrophic bladder recorded in the files of the Hospital for Sick Children (Toronto, Ontario, Canada) and Dallas Children's Hospital (Dallas, Texas) between 1953 and 1987, and identified all patients with intestinal metaplasia of the bladder.

RESULTS

A total of 53 cases were identified from both series, and none of the patients developed adenocarcinoma of the bladder. The Mayo Clinic series consisted of 24 patients. Nineteen of the 24 (79.1%) were alive without evidence of cancer (median follow-up 14 years, range 0.9 to 53), and 5 patients died of intercurrent disease (at 0.9, 4, 8, 11, and 53 years after diagnosis) without evidence of bladder cancer. The Dallas Children's Hospital and the Hospital for Sick Children series consisted of 29 patients. Twenty-seven of the 29 (93.1%) were alive without evidence of cancer (median follow-up 13 years, range 3 to 23.9). Two patients died of trauma (at 10.9 and 12 years after diagnosis) and at autopsy had no evidence of bladder cancer.

CONCLUSIONS

Intestinal metaplasia of the urinary bladder is not a strong risk factor for adenocarcinoma or urothelial cancer.