Epidemiology, treatment patterns, and clinical outcomes in de novo oligometastatic hormone‐sensitive prostate cancer

Background This study was conducted to better characterize the epidemiology, clinical outcomes, and current treatment patterns of de novo oligometastatic hormone‐sensitive prostate cancer (omHSPC) in the United States Veterans Affairs Health Care System. Methods In this observational retrospective cohort study, 400 de novo metastatic hormone‐sensitive PC (mHSPC) patients diagnosed from January 2015 to December 2020 (follow‐up through December 2021) were randomly selected. omHSPC was defined as five or less total metastases (excluding liver) by conventional imaging. Kaplan–Meier methods estimated overall survival (OS) and castration‐resistant prostate cancer (CRPC)‐free survival from mHSPC diagnosis date and a log‐rank test compared these outcomes by oligometastatic status. Results Twenty percent (79 of 400) of de novo mHSPC patients were oligometastatic. Most baseline characteristics were similar by oligometastatic status; however, men with non‐omHSPC had higher median prostate‐specific antigen at diagnosis (151.7) than omHSPC (44.1). First‐line (1L) novel hormonal therapy was similar between groups (20%); 1L chemotherapy was lower in omHSPC (5%) versus non‐omHSPC (14%). More omHSPC patients received metastasis‐directed therapy/prostate radiation therapy (14%) versus non‐omHSPC (2%). Median OS and CRPC‐free survival (in months) were higher in omHSPC versus non‐omHSPC (44.4; 95% confidence interval [CI], 33.9–not estimated vs. 26.2; 95% CI, 20.5–32.5, p = .0089 and 27.6; 95% CI, 22.1–37.2 vs. 15.3; 95% CI, 12.8–17.9, p = .0049), respectively. Conclusions Approximately 20% of de novo mHSPC were oligometastatic, and OS was significantly longer in omHSPC versus non‐omHSPC. Although potentially “curative” therapy use was higher in omHSPC versus non‐omHSPC, the percentages were still relatively low. Future studies are warranted given potential for prolonged responses with multimodal therapy inclusive of systemic and local therapies.