Comparative Trends in the Distribution of Prostate Cancer Stage at Diagnosis in the Department of Defense Cancer Registry and the Surveillance, Epidemiology, and End Results Data, 2004-2014.

Introduction: It has been demonstrated that there was an increase in later-stage prostate cancer (PCa) at diagnosis after the U.S. Preventive Services Task Force recommended against prostate-specific antigen screening for prostate cancer. However, the cancer characteristics at diagnosis within the equal-access Military Health System (MHS) during the period have not been described. In this study, we compared PCa stage at diagnosis and its trends between the military health care system and the general public and further compared the trends in tumor stage by race.

Materials and methods: This study was based on nonidentifiable data from the U.S. Department of Defense's Central Cancer Registry (CCR) and the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. Patients diagnosed between 2004 and 2014 were included. The distributions of PCa stage at diagnosis over time were compared between the 2 populations. Comparisons were further conducted for White and Black patients, respectively.

Results: Among the 11,895 patients in the CCR and 544,142 patients in SEER, the majority of patients were diagnosed with stage I or II prostate cancer. However, the CCR had a larger proportion of early-stage tumors (stages I and II combined) with 84.3% vs. 80.0% of SEER patients. The proportion of late-stage tumors (stages III and IV combined) increased over time from 2008 for both populations and the proportion of early-stage tumors decreased for the general population. In terms of temporal distributions by race, the trends were the same between White and Black groups in the general population. In the MHS, the trends in the White patients were similar to those in the general population, but in the Black patients, the percentages of stages I and II at diagnosis continued to increase and those of stages III and IV decreased, differing from those in the general population.

Conclusions: The MHS consistently diagnosed PCa at an earlier stage than the U.S. general population across all time periods evaluated in this study. Although similar trends were observed for White patients between both populations, the proportion of stages I and II at diagnosis increased from 2012 among Black patients in the MHS, which stands in sharp contrast to trends in the U.S. general population. Although the differences between the two populations may be associated with various factors, differences in accessibility to care and thus the use of prostate-specific antigen testing might play an important role.