Introduction:

Prostate cancer is the most common malignancy in men with 3.1 million cases diagnosed from 2003-2018.  Of these, 7% were stage III or stage IV.  Of note, the incidence of advanced-stage disease increased from 2010-2017.  While many studies have focused on survival outcomes in minority populations, few have aimed at understanding survival of Hispanic men and how insurance status at time of diagnosis is associated with overall survival.  Previous studies have demonstrated that in many instances, Hispanics have improved survival despite worse socioeconomic characteristics when compared to non-Hispanic Whites.  This has not been fully detailed in advanced prostate cancer.  Further, the association between insurance status at diagnosis and survival in Hispanic men with advanced prostate cancer has not been fully explored. We aim to better characterize the survival outcomes of Hispanics with advanced prostate cancer and detail associations noted between insurance status and survival in these men.

Methods:

This study was a retrospective review of the National Cancer Database from 2004-2017 and included all adult men with stage III or IV prostate cancer who underwent either a radical prostatectomy or radiation therapy. Patients were excluded if they had ≥ 1 lifetime cancer diagnosis, histology other than adenocarcinoma, no or unknown treatment, race other than Black or White, or were missing data on any of the following variables: survival time, vital status, demographic variables (facility type, primary insurance, education level, median income, patient location), PSA, and Gleason’s score. Patients were classified as Non-Hispanic White (NHW), Hispanic White (HW), or Black. A multivariate Cox regression model was built to test the association between overall survival (OS) and race/ethnicity, insurance status, and their interaction, while controlling for the variables listed in the exclusion criteria. Adjusted hazard ratios (aHR) are presented. Subgroup analysis was performed to better understand the interaction effect.

Results:

A total of 67,238 men were included in the analysis. Demographics demonstrated that NHW patients had the highest rate of private insurance, income, education when compared to HW and Black men, which demonstrated similar rates. A quarter of HW and Black men were analytic stage IV compared to 20% of NHW patients (p=<0.001). Race/ethnicity and insurance status were significantly associated with OS in the adjusted analysis; however, their interaction was not (p=0.149). Subgroup analyses revealed that within each type of insurance status, HW men had improved OS compared to NHW men, with significant differences occurring among those with private insurance/managed care (aHR: 0.73, 95% CI: 0.58-0.92) and Medicare (aHR: 0.63, 95% CI: 0.52-0.77). Similarly, HW men had improved OS compared to Black men within all insurance types, except among those who were not insured, with a significant difference occurring among those with Medicare (aHR: 0.63, 95% CI:0.51-0.77).

Conclusion:

Despite socioeconomic and demographic similarities to Black men with advanced prostate cancer as well as higher rates of stage IV disease, Hispanic men demonstrate improved overall survival compared to non-Hispanic White men. This fits what is known as the “Hispanic Paradox” as has been previously described.  It is unclear what the driving forces are for this improved survival in these men and further studies will need to focus on further granularity to better assess this phenomenon.  This data demonstrates no significant interaction between insurance status and ethnicity in regard to improved overall survival.  However, further subgroup analysis showed many interesting findings, most importantly, that HW men demonstrated improved OS compared to NHW men within each insurance status type, including those who were uninsured, and significant improvements were seen in the privately insured/managed care and Medicare subgroups.

Funding: N/A