Tumor sideness and mutational status: The potential effects on mCRC pts survival and treatment outcomes.

682Background: The treatment of mCRC has been changed with identification of different clinical behaviour of right and left sided tumors. Right-sided primary was associated with high mutational burden, worse prognosis and poor anti-EGFR response. We aimed to investigate the association between tumor site and survival, mutational status and treatment outcome of mCRC pts. Methods: The data of mCRC pts in two-cancer center in South Anatolia were retrospectively analyzed. The effects of tumor sidedness, treatment, braf on survival of mCRC pts were investigated using the log rank test. The Kaplan- Meier survival estimates were calculated. Results: A total of 210 (F/M=128/82) pts were included to study. Median age was 59.5 (range: 23-88) years. Right and left-sided tumour rates were 45 (21.7%) and 153 (72.9%), respectively. Kras, nras and braf mutation rates were 32.9, 5.5 and 6.7 %, respectively. Median follow-up was 27.5 (range: 1.3-274.3) months. In the right-sided tumors, kras (52.5 vs. 33.8 %, p=0.0034) an...