A population-based study of the incidence, mortality and outcomes in patients following surgery for colorectal cancer in Western Australia

Abstract

Background: The literature contains many reports on the management of colorectal cancer from single institutions or groups of specialist surgeons. But there are few data on community-wide patterns of treatment or the outcomes of colorectal surgery. The aim of the present study was to use a population-based linked database to assess the trends in colorectal cancer incidence and mortality in Western Australia (WA) in the period 1982-95, and to evaluate the outcomes following surgical care.

Methods: A population-based linked database was used to relate the cancer registry, hospitalization and mortality records of all patients with a diagnosis of colorectal cancer in WA during 1982-95. Data on surgical treatment and postoperative morbidity and mortality in this group of patients were available only in 1988-95. Patient records were selected using the international classification for diagnosis and procedure codes pertaining to colorectal cancer and surgery. Incidence and mortality trends in colon and rectal cancers were estimated by Poisson regression regression of age-standardized rates, and relative survival analysis was used to compare patient survival with the general population.

Results: During the 14-year period, 9673 patients presented with a diagnosis of colorectal cancer. The sex distribution of patients with colon cancer was evenly divided, but rectal cancer was more common in men (ratio 1:4). The mean age at diagnosis was 67.8 years (SD: 12.7). During the study period there was a significant increase in the standardized incidence rate of rectal cancer in men, and in the mortality rates from colon cancer in women. The overall crude 5-year survival was 57%. Large bowel resections were performed on 71% of patients with an in-hospital postoperative mortality of 4.2%.

Conclusion: Colorectal cancer is a continuing major cause of morbidity and mortality in WA. The present study demonstrated increases in the incidence rate of rectal cancer in men and in the mortality rate from colon cancer in women in the period 1982-95.