Population-based survival analysis of colorectal cancer patients in Singapore, 1968-1992

Since the 1980s, colorectal cancer incidence in Singapore has ranked second to lung in males and females. We describe a population-based analysis of survival of colorectal cancer patients diagnosed from 1968 to 1992 in Singapore. Data of colorectal cancer patients diagnosed during 1968-1992 were retrieved from the Singapore Cancer Registry. Patients were passively followed up for death to the end of 1997. The final dataset consisted of 10, 1 14 subjects. Observed and relative survival rates were calculated by stage (localized, regional metastases and distant metastases), age, ethnicity and calendar period for both genders. Over the study period, a significant progress in survival of colorectal cancer patients was observed. For localized cancer of the colon, the 5-year age-standardized relative survival (ASRS) increased from 36% in 1968-1972 to 66% in 1988-1992 for males and from 32% to 71% for females. For localized rectal cancer, the 5-year ASRS improved from 25% to 66% for males and from 23% to 66% in females. Similarly, improvement was observed in colorectal cancer patients with regional metastases, but not in those with distant metastases. Calendar year period and clinical stage of disease were identified as major significant prognostic factors of survival for colorectal cancer. The substantially improved colorectal cancer survival rates reflected the interplay of cancer control activities in various areas, such as health promotion, early diagnosis and treatment. Our study shows a unique changing pattern of survival experience for colorectal patients from a country undergoing rapid economic development. (C) 2002 Wiley-Liss, Inc.