Abstract A108: Longitudinal trends in distant metastasis at diagnosis in a racially diverse cohort of prostate cancer patients: 1990-2017
Authors: Cullen Jennifer , McCauley John , Kuo Huai-ching , Chen Yongmei , Stroup Sean , Musser John , Porter Christopher , Brand Timothy , Rice Kevin , Srivastava Shiv , Rosner Inger , Lu-ao Grace 
Published: August 2020

Introduction: Concerns for overdetection and overtreatment of clinically insignificant PCa have led to changes in PSA screening recommendations. In 2008, the US Preventive Services Task Force (USPSTF) gave PSA screening a “Grade D” recommendation for older men (≥ 75 years), and in 2012 this was extended to men of all ages. In 2017, a draft of revised guidelines was released, elevating the letter Grade to C for men aged 55-69 years. Yet three compelling studies have revealed increases in the diagnosis of metastatic PCa (mPCa) in US men. The primary aim of this study was to examine time trends in mPCa at time of diagnosis, over a 25+ year study period, in a racially diverse longitudinal cohort with equal access to health care.

Methodology: The Center for Prostate Disease Research (CPDR) Multi-Center National Database was the source of patients for this study. Men under suspicion for PCa who underwent TRUS-guided biopsy for PCa detection were eligible for enrolment into this database. This study focused on those with biopsy-confirmed PCa between January 1, 1990-December 31, 2017. Trends in mPCa at the time of diagnosis were examined for the overall cohort, as well as stratified by race (AA and CA) and patient age at CaP diagnosis (&lt;75 years versus ≥75 years). Poisson regression with a log link function was used to estimate annual percent change (APC) in mPCa at diagnosis, as a proportion of all newly diagnosed PCa per annum. Multivariable logistic regression was used to model predictors of mPCa at diagnosis as a function of PSA screening intensity prior to CaP detection and patient race.

Results: A total of 15,660 subjects met the study criteria, of whom 560 (2.8%) presented with mPCa. The decline in APC over time for the overall cohort was statistically significant (APC = -7.7%, p &lt;0.0001). When APCs were computed for across race, both AA and CA patients were observed to have statistically significant declines over time in APCs (-10.2%, p&lt;0.0001 and -7.1 %, p &lt;0.0001, respectively). However, these declines were comparable across race (p=0.07). When stratified by age group, patients ≥75 years had a smaller magnitude of decline in APC compared to those &lt;75 years (-2.7%, p&lt;0.0001 and -9.2%, p&lt;0.0001, respectively), though these declines did not differ significantly by age group (p=0.56). In multivariable analysis, both the number of prior PSA screenings (OR≥4 vs. None = 0.42, CI=0.29, 0.61, p &lt;0.0001) but not self-reported race (ORAA vs. CA=1.1, CI=0.83, 1.36, p=0.65) predicted mPCa.

Conclusions: In this longitudinal, racially diverse cohort with equal health care access, significant declines in mPCa at diagnosis were observed over a 25+ year study period. This is contrast to other recent studies that have demonstrated increases in mPCa following changes in USPSTF guidelines. There was, however, a difference in the magnitude of decrease in oldest patients (≥75 years) compared to younger men (&lt;75 years) that may have been influenced by changes in PSA screening recommendations. Continued attention to shifts in mPCa at diagnosis is needed.

Citation Format: Jennifer Cullen, John McCauley, Huai-ching Kuo, Yongmei Chen, Sean Stroup, John Musser, Christopher Porter, Timothy Brand, Kevin Rice, Shiv Srivastava, Inger Rosner, Grace Lu-ao. Longitudinal trends in distant metastasis at diagnosis in a racially diverse cohort of prostate cancer patients: 1990-2017 [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 A108.