[Adjuvant chemotherapy in cancers of the colon and rectum]

The high incidence of recurrence in patients with resected colorectal cancer at Dukes' stages B2, B3 and C indicates that these patients have micrometastases at the time of surgery and demonstrates the need for adjuvant therapy. Studies using 5-FU alone led to negative results. The combination of 5-FU and levamisole given every week during 1 year was shown to be an effective adjuvant treatment, significantly increasing survival at 5 years from 55% to 71% (p = 0.006). Other treatment modalities are under investigation. Leucovorin increases 5-FU activity in advanced cancers. A combination of the two could thus play an important role in adjuvant treatment. No results are available regarding the compared effects of 5-FU/folinic acid, 5-FU folinic acid/levamisole to 5-FU/levamisole. Portal vein chemotherapy with 5-FU administered during 7 days after surgery has been studies as well, and could also be effective. An association of a short postoperative course of intraportal chemotherapy with intravenous chemotherapy over several months may lead to a further improvement of survival in patients with colorectal cancer. Despite the substantial advances made in the adjuvant treatment of colorectal cancer, progress will be obtained only through continual research.