Investigators from Japan reported at the American Society for Clinical Oncology that patients with left-sided colon cancer have a better outcome when they are treated with a monoclonal antibody against EGFR over the widely used antibody against VEGF.
We have come to recognize that patients with left-sided and right-sided colon cancer may be somewhat different. There is a higher instance of mismatch repair in right-sided colon cancers and different biology in left-sided diseases. In this study of 823 patients, the majority had left-sided colon cancer.
The trial compared the outcome of the anti-EGFR antibody panitumumab with the anti-VEGF antibody bevacizumab. All patients received FOLFOX-6 chemotherapy.
There was a statistically significant improvement in response and overall survival for patients who received the anti-EGFR panitumumab.
In our laboratory, we have long observed the benefit of targeting EGFR in patients who are KRAS and NRAS wild type (non-mutated) leading us to use anti-EGFR antibodies inhibitors preferentially in these patients with very good and durable responses seen.
It is clear that the biology of left-sided and right-sided colon cancers differ and it is even clearer that KRAS/NRAS wild-type patients should be treated with an anti-EGFR monoclonal. We are pleased to see these confirmatory results in this Japanese trial.
Cancer patients are different from the next. Cancer biology is driven by genetics, epigenetics, and metabolism. These nuances are best examined in human tumor cultures, where the ability of drugs and combinations to induce cell death in the test tube predicts each patient’s ultimate response to therapy.