Outcomes in left versus right metastatic colorectal cancer (mCRC) in patients presenting to an inner-city safety net hospital.

Abstract

e15542 Background: Studies have shown that patients with left sided colon cancer (L-CRC) have better survival than the right sided ones. However, only few studies focused on minority population. We aim to assess the difference between left versus right sided colon cancer in an inner-city safety net hospital which has a significant proportion of minorities Methods: This is a retrospective study of 105 patients with mCRC who presented to the Medical Oncology clinic of John H Stroger Jr. Hospital of Cook County, Chicago from 2012-2014. Only those who were tested for KRAS mutation were included. Right colon cancer (R-CRC) was defined as tumor located in ascending colon and hepatic flexure. L-CRC were those arising in splenic flexure, descending colon and rectum. Chi-Square was used for categorical variables. Progression free survival (PFS) and overall survival (OS) were analyzed by Kaplan-Meier method, log-rank test and Cox proportional hazards regression models Results: Of the total population, 60.9% were African American (AA), 51.4% males, 48.5% R-CRC, 42.8% L-CRC, 5.7% Transverse-CRC, 3.8% Multicentric-CRC and 68.6% (n = 72) had documented progression. R-CRC showed poorer PFS compared to the left (median PFS 9.1 mo versus 15.1 mo, P = 0.003) but similar OS. KRAS mutation was found in 50.4% of the patients and the rate was higher in AA compared to Caucasians (57.8% versus 22.2%, P = 0.007). It was associated with a better PFS (HR 0.60; 95% CI 0.37, 0.98; P = 0.04) and a higher rate of lung metastasis on presentation (34.6% versus 16.9%, P = 0.03). There was no difference of KRAS mutation prevalence between R-CRC and L-CRC. In addition, having metastases at sites other than liver or lung at presentation was associated with worse PFS (HR 1.90; 95% CI 1.15, 3.14; P = 0.012) and OS (HR, 3.15; 95% CI 1.28, 7.78; P = 0.013) Conclusions: In our inner-city patient population presenting with metastatic CRC, right-sided tumor location and having metastases at sites other than liver or lung at presentation were associated with worse PFS, whereas KRAS mutation was associated with better PFS. Also, AA were more likely to have mutated KRAS than Caucasians, half of whom were Polish in our population