Maintenance therapy for colorectal cancer.

Maintenance therapy has become quite a hot topic for those of us working in the field of solid tumor malignancies. Our original concept of chemotherapy for solid tumors was to give a certain number of cycles and then stop treatment, or to continue treatment until an intolerable toxicity arose. Given that we now have more management tools at our disposal, and as treatments given chronically have become more tolerable, we have adapted our strategies to include an induction-like phase of more intensive chemotherapy followed by a maintenance approach of a dose-reduced, drug-changed, or modified schedule of treatment in the “maintenance” window. While maintenance treatment is now firmly established in diseases such as non–small-cell lung cancer, we have yet to establish a standard practice for maintenance therapy in metastatic colorectal cancer. Of course, ideally we could find a biomarker of benefit for patients who should be managed this way, but thus far we have had no such luck.