The Role of Local Prostate and Metastasis-Directed Radiotherapy in the Treatment of Oligometastatic Prostate Cancer

Abstract

Background/Objectives: Oligometastatic prostate cancer (OMPC) represents an early stage of metastatic disease characterized by a limited number of lesions. Recent advancements in imaging and treatment have revived interest in personalized therapies, including metastasis-directed radiotherapy (OMDRT) and primary prostate radiotherapy (PPR). This study evaluates the impact of OMDRT timing and the role of PPR on survival outcomes in OMPC patients; Methods: In this retrospective cohort study, 82 patients with OMPC who underwent OMDRT between 2010 and 2019 were analyzed. Patients were classified based on OMDRT timing (early vs. late) and disease type (synchronous vs. metachronous). Progression-free survival (PFS) and overall survival (OS) were the primary endpoints, assessed via Kaplan-Meier analysis and Cox proportional hazards models; Results: Among the patients, 36 (43.9%) had synchronous and 46 (56.1%) had metachronous OMD. With a median follow-up of 32 months, the 5-year PFS and OS rates were 77.5% and 88.5%, respectively. Early OMDRT significantly improved PFS (HR 0.461, 95% CI: 0.257-0.826, p = 0.009) and OS (HR 0.219, 95% CI: 0.080-0.603, p = 0.003). Subgroup analysis showed the most favorable outcomes for synchronous OMD patients receiving early OMDRT, with a median PFS of 22.2 months and a 5-year survival rate of 42.1%. The treatment of the primary prostate provided a survival benefit in the OS of synchronous OMD patients (5-year 83.1% vs. 50%, p = 0.025), and there was a further improvement in OS after PPR (5-year 87.7% vs. 50%, p = 0.015). Conclusions: Early OMDRT significantly enhances survival outcomes in OMPC, in both synchronous and metachronous cases. The integration of PPR can further improve results, emphasizing the importance of early intervention and personalized treatment strategies. To more definitively clarify our findings across various clinical situations, further studies with larger cohorts or prospective designs are necessary.

Keywords: metastasis-directed radiotherapy; oligometastasis; prostate cancer; radiotherapy; survival outcomes.

Figure 1

Patient subgroups by type of OMD and timing of OMDRT in this study. The orange figure represents OMD lesions, and the blue figure represents the primary prostate tumor. The yellow figure indicates that radiotherapy is being administered to each OMD lesion.

Figure 2

Kaplan-Meier survival curves for (a) OS and PFS rates after the first diagnosis of prostate cancer and (b) OS and PFS rates after OMDRT.

Figure 3

Comparison of (a) PFS rates by type of OMD and (b) PFS rates by timing of OMDRT; (c) OS rates by type of OMD and (d) OS rates by timing of OMDRT.

Figure 4

Comparison of (a) PFS and (b) OS rates across subgroups based on the type of OMD and the timing of OMDRT. Statistically significant comparison results are indicated in the figure with an asterisk (*) and bold font for the p values.

Figure 5

PFS (a–c) and OS (d–f) according to treatment approaches for the primary prostate in patients with synchronous OMD.