A population-based study of adjuvant chemotherapy for stage-II and -III colon cancers

Although clinical trials have demonstrated that adjuvant chemotherapy improves survival for stage-III colon cancer, the benefits remain controversial for stage-II lesions. The objective of the present study was to determine the extent to which adjuvant chemotherapy is used for patients with stage-II and -III colon cancers.

The study population comprised 1074 patients with stage-II and -III colon cancers diagnosed in 2000 in 12 French administrative districts and recorded in population-based cancer registries. Data were collected using a standardized procedure.

Overall, 20.4% of patients with stage II and 61.9% with stage III received adjuvant chemotherapy. Age at diagnosis was the strongest determinant of chemotherapy. Among stage-II patients, those receiving chemotherapy decreased from 57.6% in patients aged or=85. The corresponding percentages with stage III were 93.6% and 1.4%. In multivariate analyses, other factors found to be independently and significantly associated with administration of adjuvant chemotherapy for stage II were extension of the cancer (stage IIA vs. stage IIB), clinical presentation (obstruction or perforation vs. uncomplicated cancer) and discussion of the case at a multidisciplinary case-review meeting. For stage III, apart from age, discussion of the case at a multidisciplinary meeting was the only factor independently associated with administration of chemotherapy.

Adjuvant chemotherapy for stage-III colon cancer is used extensively for patients under 75 years of age. However, many elderly patients do not receive such treatment. On the other hand, a substantial percentage of stage-II colon cancer patients receive adjuvant chemotherapy despite its uncertain benefits.