Our study population was composed of prostate cancer patients at least 40 years old from the Surveillance, Epidemiology, and End Results (SEER) 18 registries database. We studied three insurance categories: insured, uninsured, and Medicaid and our primary study outcome was prostate cancer-specific survival (PCSS) based on diagnostic time period and insurance status. We designated patients as part of the pre-USPSTF era if they were diagnosed from 2010 to 2012 or the post-USPSTF era if diagnosed from 2014 to 2016. We measured PCSS with the Kaplan-Meier method and disparities with the log-rank test and Cox proportional hazards model.
Prior to the recommendation, uninsured patients observed worse PCSS than insured patients (hazard ratio 2.512, 95% CI 2.813-2.889, p<0.001). However, after the recommendation, this survival disparity narrowed due to a statistically significant decrease in PCSS among insured patients combined with no statistically significant change in PCSS among uninsured patients (HR 1.980, 95% CI 1.564-2.505, p<0.001). Upon adjusting the Cox model for variables including age, race, PSA, biopsy Gleason score (bGS), stage, and treatment, the survival disparity between insured and uninsured patients disappeared altogether (pre-USPSTF: adjusted HR 1.256, 95% CI 1.037-1.520, p=0.020; post-USPSTF: aHR 0.946, 95% CI 0.642-1.394, p=0.780). Furthermore, upon adjusting for insurance status in both the pre-and post-USPSTF Cox models, there was no survival disparity between White and Black patients (aHR 1.072, 95% CI 0.971-1.183, p=0.167). Interestingly, Medicaid patients continued to experience worse survival compared to insured patients across both the pre-and post-USPSTF eras (pre-USPSTF: aHR 1.309, 95% CI 1.157-1.481, p<0.001; post-USPSTF: aHR 1.230, 95% CI 1.040-1.454, p=0.015; p=0.553, two-tailed test).
The disappearance of PCSS disparity between insured and uninsured patients may suggest that prior to the screening recommendation, insured patients were more likely to undergo PSA screening than uninsured men due to consistent insurance coverage of PSA screening. In recommending against screening for prostate cancer, however, the USPSTF may have disproportionately discouraged insured patients from being screened, while uninsured patients were just as likely to remain unscreened. One study reported that insurance status was the most important protective factor against patients presenting with metastatic prostate cancer.1 In our previous study, which did not adjust for socioeconomic factors, we found that Black patients with prostate cancer experienced worse survival than White patients.2 However, upon adjusting for insurance status, this survival disparity disappeared, indicating that socioeconomic factors play a significant role in survival disparities between White and Black patients. Finally, unlike survival disparities between insured and uninsured patients, those between insured and Medicaid patients did not change with Medicaid patients continuing to experience worse survival. This finding is consistent with previous studies, which report that Medicaid patients with prostate cancer have higher prostate cancer-specific mortality.3
Our study had several limitations such as the assumption that insurance coverage of patients remained consistent over time and the lack of prostate cancer screening data in SEER. Therefore, this study should be considered a hypothesis-generating study.
In conclusion, the USPSTF's 2012 screening recommendation against PSA-based screening may have had unintended effects on survival disparities based on insurance status. Additionally, addressing socioeconomic factors will be critical to improving prostate cancer survival among Black patients and narrowing the survival disparity between Black and White patients.
Written by: Isaac E. Kim, Daniel D. Kim, Sinae Kim, Shuangge Ma, Thomas L. Jang, Eric A. Singer, Saum Ghodoussipour, Isaac Yi Kim
Warren Alpert Medical School, Brown University, Providence, RI, USA., Department of Biostatistics and Epidemiology, Rutgers School of Public Health, The State University of New Jersey, Piscataway, NJ, USA., Department of Epidemiology and Public Health, Yale University, New Haven, CT, USA., Section of Urologic Oncology, Rutgers Cancer Institute of New Jersey and Division of Urology, Rutgers Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA., Department of Urology, Yale School of Medicine, New Haven, CT, USA
- Aghdam N, McGunigal M, Wang H, et al. Ethnicity and insurance status predict metastatic disease presentation in prostate, breast, and non-small cell lung cancer. Cancer Med. 2020;9(15):5362–80. https://doi.org/10. 1002/cam4.3109.
- Kim IE Jr, Jang TL, Kim S, et al. Abrogation of survival disparity between Black and White individuals after the USPSTF’s 2012 prostate-specifc antigen-based prostate cancer screening recommendation. Cancer. 2020;126(23):5114–23. https://doi.org/10.1002/cncr.33179.
- Mahal AR, Mahal BA, Nguyen PL, Yu JB. Prostate cancer outcomes for men aged younger than 65 years with Medicaid versus private insurance. Cancer. 2018;124(4):752–9. https://doi.org/10.1002/cncr.31106.
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