초록

Background : Recent reports on metastatic colorectal cancer (mCRC) demonstrated that the primary tumor origin site was related to significantly different effects of biologic therapy (BT). However, in the Korean clinical field, patients are still prescribed cetuximab regardless of the primary tumor site. Therefore, it is necessary to determine whether there is a different response to BT in Korean patients as well. This study analyzed the correlation between the effect of BT and the primary tumor origin in patients with mCRC. Methods : This study included all patients diagnosed with mCRC from January 1, 2015, through December 31, 2016, who were treated with first-line chemotherapy containing bevacizumab or cetuximab. We followed the patients using EMR analysis until September 30, 2018. We compared the different effects of BT based on the primary tumor site by the time to progression (TTP) and the overall response rate (ORR). Results : One hundred and sixty-one patients were eligible for the study, 50 patients had right-sided primary tumor origins and 111 patients had tumors on the left. Among patients who received bevacizumab, there was no significant difference regardless of the primary tumor site, whereas, in patients treated with cetuximab, left-sided mCRC was related to longer TTP compared to right-sided (hazard ratio [HR]=1.92, 95% CI: 0.98 – 3.60; p=0.050). In other words, there was no significant difference between bevacizumab and cetuximab in the left-sided mCRC patients. However, in the right-sided mCRC patients, bevacizumab showed a significantly improved TTP compared to cetuximab (HR=2.08, 95% CI: 1.03 – 4.03; p=0.036). Conclusion : The primary tumor site was related to the response to BT in patients with mCRC. Right-sided primary tumor origin was associated with significantly improved TTP when treated with bevacizumab compared to cetuximab. Therefore, we recommend considering not only the molecular status but the primary tumor site when choosing BT for mCRC patients in the future.

키워드

Metastatic colorectal cancer, Right/left side primary tumor, Bevacizumab, Cetuximab, TTP, ORR

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