Abstract C071: Effect measure modification implication of area of residence in survival disadvantage of black children with renal cell carcinoma
Authors: Masire Phatsimo , Eaton Arieanna , Dabney Kirk , Holmes Larry 
Published: August 2020

Purpose: Renal cell carcinoma (RCC) is a rare but severe and aggressive pediatric malignancy. While incidence is uncommon, survival is relatively low with respect to acute lymphocytic leukemia and Wilms' tumor. The incidence of RCC and mortality vary by health variance indicators, namely sex, race, and age. However, data are unavailable on some RCC determinants, such as area of residence. We aimed to assess the temporal trends and survival in pediatric RCC (pRCC).

Methods: A retrospective cohort design was utilized to examine the event-free survival of children (0-19 years) with RCC using the Surveillance Epidemiology and End Result Data, 1973-2015. While the time-dependent variable, namely survival in months, was utilized, we assessed the predictors of survival, namely sex, age at diagnosis, education, insurance status, income, and tumor grade. In examining the joint effect of area of residence and race, as an exposure function with time, we used the Cox proportional hazard model, while the annual percent change was assessed using a generalized linear model.

Results: Between 1973-2015, there were 174 cases of pRCC, of whom 49 died (28.2%). RCC cumulative incidence tends to increase with advancing age and males (10-14) indicating a 1.6% change between 2000-2015. With respect to area of residence, mortality was higher in urban (46.7%) relative to metropolitan (26.4%). Relative to whites (17.2%), mortality was higher among blacks (47.0%). A sizable survival difference was observed with blacks relative to whites. Compared to whites, blacks were almost three times as likely to die, Hazard Ratio (HR) = 2.90, 95% Confidence Interval (CI) = 1.56-5.31. Survival was associated with sex, with males 21% more likely to die (HR = 1.21, 95% CI 0.69-2.11). Similarly, there was a nexus with age at tumor diagnosis and survival. Although imprecise, children ages 1-4, 5-9, and 10-14 were 72%, 50%, and 21%, respectively, less likely to die compared to children ages 15-19. Tumor grade, education, and income were prognostic in survival, although imprecise. The conjoint effect of area of residence and race illustrated excess risk of dying in urban relative to metropolitan areas. In the metropolitan area, the risk of dying was almost 3 times higher for blacks compared to whites (HR = 2.78, 95% CI 1.45-5.43); in urban areas there was more black survival disadvantage, HR = 4.18, 95% CI 0.84-20.80. After controlling for age, sex, education, and insurance, the risk of dying increased among blacks with RCC in metropolitan areas, a-HR = 3.37, 99% CI 1.35-8.44. Similarly, in the urban areas, after adjustment for age, sex, and insurance, there was an increased risk of dying for blacks compared to whites, a-HR = 8.87, 99% CI 2.77-281.0.

Conclusion: Pediatric RCC indicated an increased trend in males and age of diagnosis between 10-14, as well as survival disadvantage of black children. Additionally, area of residence significantly influenced racial differences in mortality.

Citation Format: Phatsimo Masire, Arieanna Eaton, Kirk Dabney, Larry Holmes Jr. Effect measure modification implication of area of residence in survival disadvantage of black children with renal cell carcinoma [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C071.