Presentation Authors: Ken Batai*, Alfredo Harb De la Rosa, Francine Gachupin, Benjamin Lee, Tucson, AZ
Introduction: Kidney cancer incidence and mortality rates vary across racial/ethnic groups in the U. S. However, the variations in clinical and pathologic characteristics of renal cell carcinoma (RCC) are not well understood in racial/ethnic minority groups that have a higher burden of kidney cancer, such as American Indians (AIs) and Hispanic Americans (HA)s. The goal of this study was to characterize RCC patients in racial/ethnic minority groups focusing on age at diagnosis and histologic subtype to generate hypothesis that will be tested in our future projects.
Methods: A total of 284 patients, including 31.6% HAs and 7.7% AIs who underwent nephrectomy at the Banner University Medical Center-Tucson (BUMCT) were included. We also analyzed data of RCC patients diagnosed between 2004-2015 (n=408,529) obtained from the National Cancer Database (NCDB).
Results: At BUMCT, HA and AI patients were diagnosed with RCC at a younger age than non-Hispanic White (NHW) patients (p < 0.001) and clear cell RCC (ccRCC) was more common in HAs and AIs than NHWs. Mean age at diagnosis in HAs was about 5 years younger than NHWs (55.8 vs. 60.5). Over 90% of HA patients had ccRCC, while only 78.8% of NHW patients had ccRCC. HAs had more than two-fold increased odds of diagnosis with ccRCC than NHWs (OR 2.79, 95% C.I.: 1.15-6.80). Among AIs, 50% were diagnosed before age 50 years, and 86.4% had ccRCC. Next, the NCDB data was analyzed to validate our findings. In the NCDB dataset, racial/ethnic minority patients were also diagnosed at a younger age than NHW patients. AIs had the lowest mean age at diagnosis (58.5 in AIs vs. 63.2 in NHWs), and 23.1% of AIs were diagnosed before age 50 years. Among HAs, Mexican Americans had low mean age at diagnosis (59.0), and 24.0% of them were diagnosed before age 50 years. ccRCC was more common in AIs (86.3%) and Mexican Americans (83.5%) than in NHWs (72.5%). AIs had 2-fold increased odds of diagnosis with ccRCC compared to NHWs (OR 2.07, 95% C.I.: 1.74-2.45) after adjusting for Charlson comorbidity score and neighborhood socioeconomic characteristics. Papillary RCC was more common in African Americans (40%) and Dominicans (24.3%) than NHWs (15.0%).
Conclusions: The majority of HAs in southern Arizona are Mexican Americans. Mexican Americans generally have a high AI genomic contribution, and Mexican American and AI RCC patients have similar characteristics. Based on these observations, we hypothesize that ancestral genomic background or ancestry related factors influence variation in age of onset and predominance of ccRCC histologic subtype.
Source of Funding: Urology Care Foundation Research Scholar Award