Optimal duration of systemic treatment in metastatic colorectal cancer

With the currently available cytotoxic and targeted drugs, metastatic colorectal cancer (mCRC) may be controlled by systemic treatment for a significant period of time. However, many questions remain about the optimal use of drugs and duration of treatment. We reviewed the data from clinical trials on the optimal duration of systemic treatment with chemotherapy and targeted therapy in mCRC patients.

The feasibility of chemotherapy-free intervals has been studied in mCRC patients treated with chemotherapy alone, but the results are conflicting. Current data show that oxaliplatin may be safely interrupted, but do not allow a firm conclusion on the safety of a full treatment break of chemotherapy. For targeted therapy, continuous inhibition of intracellular signalling by prolonged administration would theoretically be beneficial for efficacy of treatment, and has been suggested by retrospectively collected data. Recent data from a prospective study show a clinical benefit for maintenance treatment with chemotherapy and bevacizumab with acceptable toxicity and preservation of quality of life. Survival benefits were seen in selected patient subgroups. No data on the optimal duration of treatment with anti-epidermal growth factor receptor agents are currently available.

There are no definite data on the safety of chemotherapy-free intervals. Data on targeted therapy support the use of maintenance treatment of chemotherapy plus bevacizumab.