3201 - Demographic differences between consenting versus non-consenting participants for biospecimen collection on NRG prostate cancer trials

S. C. Kamran¹, M. Borges², D. E. Spratt³, N. Vapiwala⁴, J. A. Efstathiou⁵, D. T. Miyamoto¹, K. W. Mouw⁶, M. A. L. Vyfhuis⁷, Q. T. Le⁸, H. Willers⁹, E. M. Van Allen¹⁰, F. W. Huang¹¹, J. M. Michalski¹², J. P. Bahary¹³, J. Helou¹⁴, H. Lukka¹⁵, S. Pugh², J. Wenzel¹⁶, F. Y. Feng¹⁷, and P. T. Tran¹⁸; ¹Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, ²NRG Oncology Statistics and Data Management Center, Philadelphia, PA, ³Case Western, Cleveland, OH, ⁴Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, ⁵Department of Radiation Oncology, Harvard School of Medicine, Boston, MA, ⁶Department of Radiation Oncology, Brigham and Women’s Hospital/Dana-Farber Cancer Institute, Boston, MA, ⁷Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, ⁸Stanford University, Stanford, CA, ⁹Massachusetts General Hospital, Boston, MA, ¹⁰Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, ¹¹Division of Hematology and Oncology, Department of Medicine, University of California San Francisco, San Francisco, CA, ¹²Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, ¹³Department of Radiation Oncology, Centre Hospitalier de lUniversité de Montréal, Montreal, Quebec, Montreal, QC, Canada, ¹⁴Department of Oncology, Western University, London, ON, Canada, ¹⁵Juravinski Cancer Centre, Hamilton, ON, Canada, ¹⁶Johns Hopkins, Baltimore, MD, ¹⁷Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, ¹⁸Johns Hopkins University, School of Medicine, Baltimore, MD

Purpose/Objective(s): Precision medicine (PM) has revolutionized oncology; however, tumor biomarkers are derived primarily from a homogenous population, not reflective of the diverse cancer population. NRG Oncology (NRG) has completed large practice changing clinical trials and encouraged biospecimen collection. We evaluated differences between patients who participated in NRG prostate cancer (PCa) trials versus those who also participated in biospecimen collection. Our hypothesis was that disparities exist in the NRG biobank collection that could further compound inequities in PM. Materials/

Methods: NRG PCa trials closed before 2015 were analyzed for patients who consented to biospecimen collection. We used t-tests and chi-square tests for continuous and categorical variables, respectively. Spearman correlation coefficients were used to assess the association between zip code area deprivation index (ADI; assessed continuously and categorized by highest quartile vs lowest 3 quartiles) and median income for model testing. Logistic regression models were used to assess the effect of various demographic factors.
Results: Of 6721 randomized patients, 5485 (81.6%) consented to biospecimen collection. A smaller proportion of non-White patients consented to specimen collection as compared to those who did not consent (17.6% vs. 25.9%, respectively; p<0.0001). Furthermore, patients who resided in neighborhoods with a greater socioeconomic disadvantage, as indicated by a higher ADI, were also less likely to consent to specimen collection, when compared to those who had a lower ADI (45.7% vs. 41.5%, respectively; p=0.0004), however, there was no difference in zip code median income between the two groups. In univariate logistic regression models, ADI (categorical and continuous) was associated with a decreased likelihood for specimen consent (OR=0.85, OR=0.99, respectively, p<0.05 for both). Hispanic/Latino (OR=0.61, OR=0.56) and non-White patients (OR=0.59, OR=0.57) were less likely to consent to biospecimen collection in models with ADI as a predictor (categorical and continuous, respectively, p<0.001 for all). Non-White patients were less likely to consent to specimen collection (OR=0.54; p<0.0001) in the model with median income as a predictor, where median income was not significantly associated with likelihood of specimen consent.
Conclusion: Although >80% of NRG PCa trial participants consented to biospecimen collection, patients who were non-White, Hispanic/Latino or who lived in zip codes with higher ADI were less likely to participate in specimen collection. Recognition and further understanding of these disparities can lead to targeted, sustainable improvements for biospecimen collection on NRG PCa clinical trials so that biorepositories and PM approaches can better reflect the trial participants and overall population.