Abstract B027: Disparities in care by race and ethnicity for rectosigmoid cancer patients
Authors: Tambe Beverly , Noren Erik , Mirza Kasim , Wang Clara V. , Duldulao M. Philip , Lee Sang W. , Barzi Afsaneh 
Published: August 2020

Methods: Los Angeles Cancer Surveillance Data was queried for patients with rectal and rectosigmoid cancer (ICD-O-3 199187, 189, and 209) diagnosed between May 2004-August 2017. Only patients with clinical stage were included in this analysis. We assessed patterns of care for early-stage disease and survival in this population. Unadjusted Cox-proportional hazards regression models were used to assess associations between patient characteristics and survival and between race/ethnicity and survival by presenting stage. A nearest neighbor propensity score matching algorithm that accounted for presenting stage and age at diagnosis using a 1:2 matching ratio was used to select a balanced subset of parents for a Cox proportional hazards regression model to assess the association between neoadjuvant radiation and survival by race/ethnicity.

Results: A total of 2452 patients were included in this analysis. The median age of the population was 57.8,% female, 35% were non-Hispanic White (NHW), 7% Black, 19% Asian, 37% Hispanics. Presenting stage was 0 for 4% of the population, 13% Stage 1, 13% Stage 2, 23% Stage 3, and 26% Stage 4. Presenting stage was not reported for 22% of patients. Compared to non-Hispanic White (NHWs), there is weak evidence that Blacks and Hispanics had poorer survival, HR 1.26 (95% CI: 0.99, 1.61) and 1.14 (95% CI: 0.98, 1.33), respectively. The stage-specific survival was similar for stage I, II, and III, and stage IV patients had poorer survival. Use of neoadjuvant radiation (NAR) was assessed in this population. Nineteen percent of patients received NAR and 60% of those had presented at stage II and or III. Receipt of NAR was associated with better survival in the population: HR 0.59 (95% CI: [0.5, -0.7]) p-value &lt; 0.001). The receipt of NAR was significantly higher in NHWs and lower in all other racial/ethnic groups. The interaction between race/ethnicity and benefit from NAR was assessed in a matched cohort by stage and age; Hispanics appeared to draw the most benefit from neoadjuvant radiation (NAR); however, many of the estimates are imprecise due to low sample size. Gender was also not available in the database and was not included in our final analysis.

Conclusion: We show that there is a disparity in the patterns of care by race and ethnicity. Despite the observation that Hispanics achieve the most benefit from NAR, they receive lower rates of radiation compared to NHWs.

Note: This abstract was not presented at the conference.

Citation Format: Beverly Tambe, Erik Noren, Kasim Mirza, Clara V. Wang, M. Philip Duldulao, Sang W. Lee, Afsaneh Barzi. Disparities in care by race and ethnicity for rectosigmoid cancer patients [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 B027.