The Effect of Primary Tumor Site on Survival in Metastatic Colorectal Cancer Patients and their Relation to KRAS and Biological Therapy | ||||
| SECI Oncology Journal | ||||
| Volume 11, Issue 2, May 2023, Page 139-145 | ||||
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| Abstract | ||||
| Background: Depending on whether the primary tumor site is in the right or left colon, previous investigations have indicated differences in biology and prognosis for colorectal cancer. Further divisions into right, left and rectum or even exact primary site have also been analyzed. Possible differences in response to biological agents have also been reported based on primary tumor site. Methods: We performed a retrospective analysis on 165 metastatic colorectal cancer (mCRC) patients treated in clinical oncology department, Assiut university hospital, Egypt from January 2015 to December 2019. Patients were divided according to their primary site into: right sided colon cancer, left sided colon cancer and rectal cancer. In this study the effect of primary site on survival and their relation to KRAS status and biological therapy were evaluated. Results: 165 patients were analyzed, mean age was 42 years. Progression free survival (PFS) and overall survival (OS) of right sided tumors were less than survival in left sided tumors and rectum with significant P value for PFS 0.001 and OS 0.01. As for patients who received biological therapy, right sided tumors were associated with decreased OS compared with left sided and rectal tumors with significant P-value; for Panitumumab (P value < 0.001), Cetuximab (P value 0.002), Bevacizumab with wild KRAS (P value 0.3) which was not significant and Bevacizumab with mutant KRAS (P value < 0.001). In right sided wild KRAS tumors, patients who received anti epidermal growth factor receptor (EGFR) therapy had worse OS than vascular endothelial growth factor (VEGF) monoclonal antibody, with OS of anti EGFR was 23 months for panitumumab and 21 months for cetuximab whereas in VEGF monoclonal antibody (Bevacizumab), OS was 30 months. In left sided and rectal wild KRAS tumors, patients who received anti EGFR therapy had better OS than VEGF monoclonal antibody, with OS for left sided and rectal cancer who received panitumumab was 43 and 42 months respectively and for cetuximab 46 and 43 months respectively, whereas for Bevacizumab OS was 35 and 36 months respectively. Conclusion: Patients with right sided mCRC have worse survival than those with left sided and rectal tumors. In patients with wild type KRAS tumors treatment with anti EGFR therapy showed better survival than bevacizumab in patients with left sided and rectal tumors and was associated with worse survival among those with right sided tumors. | ||||
| Keywords | ||||
| Metastatic colorectal cancer; Primary site; Survival; KRAS; Biological therapy | ||||
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