Cholecystectomy and colorectal cancer in China

Colorectal cancer is a major public health problem in China: 79,800 new cases are estimated to occur each year, which ranks it among the five most common tumours in China. Although the association between cholecystectomy and colorectal cancer has been studied elsewhere, few studies have been conducted in the Chinese population, characterized by a lower fat intake, and low colorectal cancer incidence. We conducted this hospital-based case-control study to explore this association. The study included a total of 503 incident cases with pathologically diagnosed colorectal cancer in Drum Tower Hospital at Nanjing in China from 1965 to 1986, and 2188 healthy controls who had annual routine physical examinations at the same hospital. Diagnosis of cholelithiasis was confirmed by ultrasonography or X-ray cholecystography, and the information on cholecystectomy was obtained by checking medical charts for both cases and controls. The prevalence of cholelithiases was 5.8% for cases and 6.1% for controls (P > 0.05). Eight cases (1.6%) and 18 controls (0.8%) had a history of previous cholecystectomy. The period between cases' cholecystectomy and diagnosis of colorectal cancer ranged from 2.5 to 23 years, and the mean interval was 8.9 years. The crude odds ratio for patients having previous cholecystectomy is 1.95 (95% CI: 0.84-4.51) compared with controls. The odds ratio for female patients with previous cholecystectomy was 2.79 (95% CI: 1.03-7.59). When subsites were analysed, a significant association between right colon cancer and cholecystectomy was noted: the odds ratio was 6.2 (95% CI: 2.24-16.9), and that for females was even higher 8.61 (95% CI: 2.44-3.04) with statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)