Treatment Selection in RAS Wild-Type mCRC

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The large amount of data that have been collected for upfront treatment of metastatic colorectal cancer (mCRC) allows for a more individualized treatment approach for many patients. This personalization should extend beyond frontline therapy, as the frontline therapy utilized is likely not as important as the overarching treatment strategy, notes Axel Grothey, MD.

For RAS wild-type unresectable metastatic tumors, there is clearly a choice between cetuximab or panitumumab and bevacizumab with FOLFOX or FOLFIRI, based on the FIRE-3 and SWOG/CALGB 80405 data. There are nuances in terms of efficacy and toxicity between each of these therapies. When tumor burden is a large concern, there may be an advantage to using an EGFR antibody over bevacizumab, says Grothey. Since most patients are not in that situation, toxicity becomes more of an issue.

When considering the continuum of care, bevacizumab lends itself to a maintenance plan, and it can also be used beyond progression and as second-line therapy. Delaying anti-EGFR therapy also delays the onset of rash and gastrointestinal toxicities, Grothey suggests. Additionally, data from the phase III 80405 and EPIC trials has not clarified the role for an EGFR inhibitor in patients with operable liver metastases.