[Results of chemotherapy in cancers of the colon]

With 25,700 new cases a year, colorectal cancer is the most common cancer in France. Until the late 80s, the only effective treatment was surgical excision. However, chemotherapy (palliative and adjuvant) has made great progress and interesting results have begun to be published, especially since 1990. Palliative treatment: the rate of tumor reduction is two times higher when using a combination of 5FU and folinic acid rather than 5FU alone and, according to some studies, this combination might significantly improve the duration and quality of survival. Two recent controlled studies, comparing systemic chemotherapy with symptomatic treatment, showed a significant improvement in the duration of survival and a study in asymptomatic patients indicated a significant extension of the duration of the symptom-free period. Intra-arterial hepatic chemotherapy significantly improves the survival but toxicity is high. Further clinical testing is needed to evaluate new agents and to improve response rates and tolerance to treatment. More study will also be required to evaluate chemotherapy as debulking of initially inoperable metastasis. Adjuvant treatment: in Dukes stage C colonic cancer a combined regimen using 5FU and levamisole is now the standard treatment and reduces the relative risk of recurrence and death by 41 and 33% respectively. A combination of 5FU and folinic acid has been shown at least as effective in term of 3 year outcome in three studies. Current studies have not demonstrated the efficacy of chemotherapy in patients with Dukes B colonic cancer. Efficacy is probably marginal and clearly lower than for stage C. USe of new prognostic factors such as ploidy which appears to be an independent and reliable predictor of the risk of recurrence in stage B patients, should allow accurate identification of patients able to benefit from adjuvant treatment. Some findings support early postoperative use of intraportal chemotherapy. Present trials in stage B and C patients which no longer include untreated control groups are under way to compare systemic treatments (5FU-levamisole, 5FU-AF-levamisole) or combination of locoregional and systemic treatments (intraperitoneal or intraportal 5FU and systemic treatment vs systemic treatment alone). One such trial is the recently begun European study that is to include 2000 patients upon completion. Development of large-scale controlled trials will be necessary to build on the major gains that have been made in adjuvant treatment.