Primary tumor side influences metastatic CRC biologic agent response
medwireNews: The primary tumor side is a key determinant of response to the biologic agents bevacizumab or cetuximab in patients with metastatic colorectal cancer (CRC), indicates a population-based cohort study.
The results, based on data from the California Cancer Registry of11,905 metastatic CRC patients treated with either chemotherapy alone or alongside bevacizumab or cetuximab, confirm those of clinical trials showing differential survival depending on whether the primary tumor originated on the left or right side of the colon, the study authors say in JAMA Surgery.
They found that patients with left-sided tumors derived a survival benefit from adding either bevacizumab or cetuximab to systemic chemotherapy, with corresponding hazard ratios (HRs) of 0.88 and 0.82 relative to chemotherapy alone.
But although bevacizumab use remained associated with improved overall survival among those with right-sided tumors (HR=0.93 vs chemotherapy), this was not the case for cetuximab, the use of which significantly increased mortality risk (HR=1.31 vs chemotherapy).
Maheswari Senthil (Loma Linda School of Medicine, California, USA) and colleagues believe that their findings “have important treatment and health care cost implications” and they add that “[s]election of appropriate [biologic therapy] based on primary tumor site and response may help eliminate ineffective and expensive treatment in patients with [metastatic] CRC.”
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