Current Status of Adjuvant Therapy for Colorectal Cancer
May 01, 2004
Adjuvant therapy with chemotherapy and/or radiation therapy inaddition to surgery improves outcome for patients with high-risk carcinomasof the colon or rectum. For colon cancer, fluorouracil (5-FU)combined with leucovorin is a current standard of care that improveslong-term survival. A recent European trial (MOSAIC) has documentedsignificant improvement in 3-year disease-free survival when oxaliplatin(Eloxatin) was added to infusional 5-FU and leucovorin in the FOLFOXregimen. Two US cooperative group trials will evaluate the addition ofantiangiogenesis therapy with bevacizumab (Avastin) to chemotherapy.A third trial will evaluate FOLFOX, irinotecan (Camptosar) combinedwith infusional 5-FU and leucovorin (FOLFIRI), and the sequentialuse of FOLFOX followed by FOLFIRI. In rectal cancer, postoperative5-FU–based chemotherapy combined with irradiation can improve bothlocal tumor control and survival. The German Rectal Cancer Grouphas recently reported that preoperative combined-modality therapy isless toxic and more effective in preventing local tumor relapse comparedto similar treatment given postoperatively. A coordinated pair ofcooperative group clinical trials will evaluate oral capecitabine (Xeloda)as a radiation enhancer in the preoperative setting, and the FOLFOXand FOLFIRI regimens compared to 5-FU and leucovorin followingsurgery. Predictive and prognostic molecular markers will be studiedin these new adjuvant therapy clinical trials for both colon and rectalcancer with the goal of developing future regimens tailored to individualpatients. There has been a recent and dramatic increase in thepace of drug development for colorectal cancer which holds promise tofurther improve curative therapy as part of a multidisciplinary approachin the surgical adjuvant setting.