Racial differences in prognostic role of white blood cell ratios in gastrointestinal stromal tumors

e23507 Background: Gastrointestinal stromal tumors (GIST) are rare mesenchymal tumors with an estimated 3,300 to 6,000 new cases per year in the United States. Per SEER database, significant racial disparity exists with an incidence rate twice as high for African Americans as compared to Whites. Currently, parameters used in stratification of disease risk can only be determined by postoperative histopathological evaluation. Cancer-related inflammation is linked to different stages of tumor development so markers found in peripheral blood have been studied as surrogates. We present a study comparing the predictive prognostic ability of preoperative serum inflammatory markers in primary untreated GIST and highlight the differences between Black and White patients. Methods: This is a retrospective analysis of 149 patients who underwent operative resection of primary untreated GIST. Preoperative blood samples were used for the analysis. Patients were excluded if they showed clinical signs of infection during time of pre-operative blood sampling or had non-GIST synchronous malignancy. Clinicopathological data was obtained from patient chart review and logistic regression models were used to evaluate data. There is ongoing next-generation sequencing data analysis. Results: 149 patients were included: 80 (53.7%) Black, 43 (28.9%) White, 26 (17.5%) were other. The mean values for neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and monocyte to lymphocyte ratio (MLR) were 3.62 (SD 3.07), 191.55 (SD 119.15), and 0.47 (SD 0.49) respectively. On univariate analysis NLR and PLR were significant prognostic indicators of high and intermediate risk GISTs per the National Institute of Health (NIH) categories [NLR p = 0.008, PLR p = 0.007]. Upon subgroup analysis, NLR and PLR showed the highest statistical significance for predictors of high and intermediate risk GISTs among the Black patient population [NLR odds ratio (OR) 2.685; 95% confidence interval (CI) 0.976-7.381; p = 0.05 and PLR OR 1.792; 95% CI 1.054-3.049; p = 0.031]. The same was not shown to be true for the White patient population. 11 out 149 patients progressed since diagnosis of which 8 were Black and 3 White. 7 were in the high risk category, 3 in low risk and 1 in intermediate risk with an overall mean NLR and PLR 5.25 and 244 respectively. The average time to progression was noted to 28 months. Conclusions: The NLR and PLR are easily obtainable and cost-effective indexes which have the prognostic ability to serve as surrogates for high and intermediate risk GISTs. They appear to be more predictive in the Black patient population than in White. Further study is warranted for incorporation into risk stratification systems.