Onkológia 5/2017

The application of biological treatment in metastatic colorectal carcinoma in relation to primary tumor localization

Backgrounds: Metastatic colorectal cancer (mCRC) is heterogeneous, and primary tumours arising from different regions of the colon are clinically and molecularly distinct. Retrospective analyses are assessing the impact of biological therapy on progression-free survival (PFS), overall survival (OS) and objective response rate (ORR) according to tumor location and biological treatment . Materials and metods: We are presenting treatment results for a group of patients with mCRC treated with chemotherapy and biological therapy and relation to tumour localisation and KRAS status at our department between 2010-2017. Results: Median of overall survival (OS) in patients with mCRC, treated with any biological therapy in combination with cytostatic therapy minimally in 1st line, was in our group 27,63 months as to patients with the left side tumors; 16,58 months as to patients with the right side tumors (28,2 months as to patients with rectal tumors). Median of overall survival (OS) and progression free survival (PFS), respectively, in patients treated in 1st line with anti-EGFR therapy in combination with chemotherapy was in patients with left side tumors 30 months and 15 months; in patients with right side tumors reached 12 month s and 7 months; patients with rectal tumors had OS 31 months and PFS 17,5 months. Median of OS and PFS, in patients treated in 1st line with anti-VEGF therapy in combination with chemotherapy was in patients with left side tumors 24 months and 9 months; in patients with right side tumors was OS 17 month s and PFS 7 months; patients with rectal tumors had OS 19,5 months and PFS 8 months. Conclusion: There was no significant difference in overall survival (OS) in patients with tumours either on left side or right side according to 1st line biological therapy. There was a statistically significant PFS improvement in patients with WT mCRC with left side tumours receiving anti-EGFR therapy in first line compareded to patients receiving first line anti -VEGFR therapy ( median PFS 15 versus 9 months, p = 0.02). In subanalysis of the patient group with rectal carcinoma there was statistically significant difference in OS and also PFS depending on 1st line biological therapy used in favour of anti-EGFR therapy in KRAS WT patients.

Keywords: metastatic colorectal cancer, tumour sideness, biologocal therapy, KRAS mutation