Epidemiology of cancer of the large bowel--the 12-year experience of a specialized registry in northern Italy.

BACKGROUND

In 1984, a specialized colorectal cancer registry was instituted in Modena; aims of the Registry were: the evaluation of incidence and mortality, the study of morphological aspects, staging, survival and familiarity of the registered patients.

AIMS

Purpose of the research was to provide an updated description of the main findings (in particular, incidence, staging, morphology and survival) observed in the 12-year registration period.

PATIENTS AND METHODS

Between January 1984 and December 1995, 1,899 malignancies of the large bowel in 1,831 patients were registered. Tumours were classified according to the International Classification of the Diseases for Oncology (ICDO) and staged with the TNM system. Cancer specific survival was assessed with life table analysis and Log-Rank tests.

RESULTS

Crude incidence rate showed minor fluctuations between 1984 and 1989, but tended to rise in the following years. Tumours were mostly located distal to the splenic flexure (73.3% of the total), with a slight tendency over time to a gradual "shift" to the right colon. Staging became progressively more favourable throughout the registration; in 1984 both stages I, II and stage IV + unstaged lesions represented 40% of the total, but in 1995 the former rose to 50% whereas the latter fell to 21.6% (p < 0.001). This move to earlier stages resulted in an improved survival of patients registered in 1990-91 versus 1984-85 (Log-Rank 14.3 p < 0.002). Factors associated with a poor survival were the advanced age of patients at diagnosis (> 74) and clinical stage.