Incidence and survival of patients with Dukes' A (stages T1 and T2) colorectal carcinoma: a 15-year population-based study.

BACKGROUND AND AIMS: Patients with stage I (Dukes' A) colorectal carcinoma tend to show a good prognosis; however, recurrences can be observed in some patients. Through a specialized colorectal cancer Registry, we attempted to investigate the epidemiological and clinical features of individuals with Dukes' A neoplasms.PATIENTS AND METHODS: From 1984 to 1998, 295 individuals were diagnosed with Stage I /Dukes' A tumors; 150 of these had lesions infiltrating the muscular wall (T2), while 145 had neoplasms limited to the submucosa (T1).RESULTS: Dukes' A tumors represented 13.8% of all registered neoplasms; the percentage doubled over the study period (8.1% in the first year vs. 16.8% in the final year). In each year of observation, the preferential locations were the rectum and sigmoid colon (75% of all lesions). Most patients required surgery, but only 21.3% could be managed by endoscopic polypectomy. Overall 5-year survival was 81.0% (82.1% in T1, 80.0% in T2). Recurrences were seen in 6.8% (2.8% in T1, 10.7% in T2), while 36 patients (12.2%) died of causes unrelated to colorectal cancer. In 17 out of 20 patients who died of cancer, the lesions were localized in the rectosigmoid region. Survival analysis showed a significantly better prognosis (P<0.007) for patients with T1 tumors.CONCLUSIONS: The proportion of stage I colorectal tumors tended to increase over time. Although the overall prognosis is good in four-fifths of the cases, approximately one-fifth of these patients die of recurrent disease or of other causes. As expected, the prognosis was significantly more favorable for patients with T1 lesions. For patients with T2 tumors, radical surgery is the most appropriate approach.