The role of maintenance strategies in metastatic colorectal cancer
Results from a systematic review published in JAMA Oncology found that maintenance chemotherapy following initial chemotherapy appeared to be more beneficial for patients with metastatic colorectal cancer (mCRC) than continuing a full induction chemotherapy regimen until disease progression.
Systematic review: a review of a clearly formulated question that uses systematic and reproducible methods to identify, select and critically analyze all relevant research, and to collect and analyse data from the studies that are included in the review
Induction chemotherapy: chemotherapy given before the initiation of another treatment. May also be referred to as initial or first-line chemotherapy.
Maintenance chemotherapy: chemotherapy given in lower doses to assist in prolonging the anti-cancer effects of induction chemotherapy
These findings suggest that for some patients, switching to a lighter, less intensive maintenance regimen of chemotherapy or even taking a break in treatment may be appropriate, with a return to a full chemotherapy regimen if the disease progresses. Given that the goal of therapy in mCRC is to prolong life while preserving or improving quality of life, it is important to prioritize treatments that achieve the maximum benefit with the fewest side effects. Given that chemotherapy regimens come with varying levels of toxicity, gaining a better understanding of how to optimize treatment intensity and duration is of utmost importance.
Patients with advanced mCRC will typically receive chemotherapy in combination with a targeted therapy drug. The duration of first-line induction chemotherapy after achieving the maximum disease response has remained a subject of controversy due to the toxicities that can occur after prolonged treatment.
Results from the systematic review of the relevant randomized clinical trials found that there was no additional survival benefit of continuing full induction chemotherapy until disease progression compared with observation (no treatment). When compared to observation, patients who received maintenance chemotherapy experienced a progression-free survival benefit, but no overall survival benefit. Maintenance chemotherapy containing 5-FU with or without the targeted therapy drug bevacizumab, showed significant improvement in PFS compared to observation alone.
The researchers highlight that many chemotherapies are initially beneficial to patients in shrinking and controlling the cancer. After a few months of therapy, however, the maximum benefit is usually reached. At this point, the focus might be directed towards how to best prolong that benefit while reducing toxicities and side effects. These study findings confirm that less-intensive chemotherapy regimens are appropriate and effective in prolonging progression-free survival outcomes, and that the use of more intensive chemotherapy regimens should be reserved for instances of disease progression.
Take away message:
Findings demonstrate that less-intensive maintenance chemotherapy may be an appropriate alternative for the treatment of patients with mCRC who have achieved maximum benefit from initial induction chemotherapy. Induction chemotherapy can be given if disease progression occurs, but lighter maintenance therapy can help to minimize toxicities and side effects while prolonging the anti-tumour benefits of initial chemotherapy.