Abstract PO-007: Racial and ethnic differences in capecitabine toxicity in colorectal cancer patients

Abstract Abstract: Purpose: Capecitabine is commonly used as a first-line treatment for gastrointestinal (GI) tract cancers. Common toxicities of capecitabine include diarrhea and hand-foot syndrome (HFS), which frequently lead to dose reduction, interruption, and even discontinuation. While racial and ethnic differences in capecitabine toxicities have been suggested by case reports, they have not been systematically evaluated in diverse ‘real-world’ populations. This study examined differences in capecitabine-related diarrhea, HFS, dose-reduction, and discontinuation among patients of different racial and ethnic backgrounds. Methods: In this retrospective chart review study, the electronic medical records of patients receiving first-line capecitabine-containing regimens for GI malignancies were reviewed. Patients on regimens containing irinotecan or radiation were excluded due to overlapping toxicities. Concurrent non-neoplastic medications were also recorded. Multiple logistic regression models were used to test for an association between race/ethnicity with any capecitabine toxicities while adjusting for other demographic characteristics. Results: One hundred twenty-five patients diagnosed with either colon [N=76 (60.8%)], rectal [N=22 (17.6%)], gastric [N=16 (12.8%)], or other GI cancers [N=11 (8.8%)] were included. In logistic regression analysis, diarrhea occurrence was significantly lower in the African-American/non-Hispanic [OR(95% CI): 0.25 (0.08, 0.75) p value<0.01] compared to Caucasian non-Hispanic population. There was increased risk of HFS in African-American/non-Hispanic [OR (95% CI): 2.26 (0.86, 5.95); p value=0.09], although this result did not reach statistical significance. Additionally, the occurrence of dose-reduction was significantly higher in the African- American/non-Hispanic population [OR(95% CI): 5.83(1.49, 22.80) p value<0.01] and in the Caucasian/Hispanic population [OR(95% CI): 4.49(1.09, 18.42) p value<0.05] as compared to Caucasian non-Hispanic population. Conclusion: By identifying racial and ethnic differences in the incidence and onset of capecitabine toxicities in patients with GI malignancies, our study may help clinicians risk stratify, counsel, and manage patients receiving capecitabine-containing regimens. Our study also emphasizes the need to understand the relationship between the incidence of toxicities and dose reductions or discontinuation of therapy in racial and ethnic minorities. Citation Format: Soham D. Yande, Alicia Brazelton, Rita Pope, Michael Johnson, Benjamin Musher, Meghana V. Trivedi. Racial and ethnic differences in capecitabine toxicity in colorectal cancer patients [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-007.