Guidelines recommend prostate-specific antigen (PSA) surveillance among men treated with definitive radiation therapy (RT) for prostate cancer. Specifically, the National Comprehensive Cancer Network recommends testing every 6 to 12 months for 5 years and annually thereafter (with no specific stopping period specified), while the American Urology Association recommends testing for at least 10 years, with the frequency to be determined by the risk of relapse and patient preferences for monitoring.1,2 Salvage treatments exist for men with localized recurrence identified early through PSA testing, so adherence to follow-up guidelines is important for quality prostate cancer survivorship care.1,2
However, few studies focus on adherence to PSA surveillance following radiation therapy. Posttreatment surveillance among surgical patients is generally high, but sociodemographic disparities exist. Racial and ethnic minorities and unmarried men are less likely to undergo guideline concordant surveillance than is the general population, potentially preventing effective salvage therapy.3,4 A recent Department of Veterans Affairs (VA) study on posttreatment surveillance included radiation therapy patients but did not examine the impact of younger age, concurrent androgen deprivation therapy (ADT), or treatment facility (ie, diagnosed and treated at the same vs different facilities, with the latter including a separate VA facility or the community) on surveillance patterns.5 The latter is particularly relevant given increasing efforts to coordinate care outside the VA delivery system supported by the 2018 VA Maintaining Systems and Strengthening Integrated Outside Networks (MISSION) Act. Furthermore, these patient, treatment, and delivery system factors may each uniquely contribute to whether patients receive guideline-recommended PSA surveillance after prostate cancer treatment.
For these reasons, we conducted a study to better understand determinants of adherence to guideline-recommended PSA surveillance among veterans undergoing definitive radiation therapy with or without concurrent ADT. Our study uniquely included both elderly and nonelderly patients as well as investigated relationships between treatment at or away from the diagnosing facility. Although we found high overall levels of adherence to PSA surveillance, our findings do offer insights into determinants associated with worse adherence and provide opportunities to improve prostate cancer survivorship care after RT.
Methods
This study population included men with biopsy-proven nonmetastatic incident prostate cancer diagnosed between January 2005 and December 2008, with follow-up through 2012, identified using the VA Central Cancer Registry. We included men who underwent definitive RT with or without concurrent ADT injections, determined using the VA pharmacy files. We excluded men with a prior diagnosis of prostate or other malignancy (given the presence of other malignancies might affect life expectancy and surveillance patterns), hospice enrollment within 30 days, diagnosis at autopsy, and those treated with radical prostatectomy. We extracted cancer registry data, including biopsy Gleason score, pretreatment PSA level, clinical tumor stage, and whether RT was delivered at the patient’s diagnosing facility. For the latter, we used data on radiation location coded by the tumor registrar. We also collected demographic information, including age at diagnosis, race, ethnicity, marital status, and ZIP code. We used diagnosis codes to determine Charlson comorbidity scores similar to prior studies.6-8
