Oligoprogression During First-Line Treatment of Metastatic Hormone-Sensitive Prostate Cancer: Comparative Outcomes of...

Background/Objectives: We evaluated the clinical outcomes of two commonly used approaches for managing oligoprogression arising during first-line therapy for metastatic hormone-sensitive prostate cancer (mHSPC): metastasis-directed radiotherapy (RT) with continuation of the ongoing systemic regimen and immediate transition to another systemic treatment. Methods: A total of 81 patients with mHSPC who experienced radiologically confirmed oligoprogression during first-line systemic therapy were retrospectively evaluated. Oligoprogression was defined as progression involving three or fewer metastatic sites. Patients were categorized into an RT group (metastasis-directed RT with continuation of the same regimen) or a treatment-change group (immediate switch in systemic therapy without RT). Post-oligoprogression radiologic progression-free survival (rPFS) and overall survival (OS) were evaluated using Kaplan-Meier estimates and Cox proportional hazards models. Results: Thirty-one patients received metastasis-directed RT, whereas fifty underwent a change in systemic therapy. The median post-oligoprogression rPFS was 25.8 months (95% CI, 16.3-35.2) in the entire cohort and did not differ significantly between the treatment-change (26.8 months) and RT groups (22.7 months; p = 0.828). The median OS was 42.6 months overall, with comparable outcomes between the treatment-change (42.6 months) and RT groups (52.4 months; p = 0.452). Conclusions: In patients with mHSPC who developed oligoprogression during first-line systemic therapy, metastasis-directed RT with continuation of the same regimen and immediate change in systemic treatment were associated with comparable post-oligoprogression outcomes in our cohort. These findings suggest that both strategies may be feasible in selected patients. Prospective studies may help clarify which patients are more likely to benefit from each strategy.