Progression-directed therapy in patients with oligoprogressive castration-resistant prostate cancer.

Purpose: Oligoprogressive lesions are observed in a subset of patients who progress to castration-resistant prostate cancer (CRPC), while other lesions remain controlled by systemic therapy. This study evaluates the impact of progression-directed therapy (PDT) on these oligoprogressive lesions.

Materials and methods: This retrospective study included 40 patients diagnosed with oligoprogressive CRPC. PDT was performed for treating all progressive sites using radiotherapy. Fifteen patients received PDT using radiotherapy for all progressive sites (PDT group) while 25 had additional first-line systemic treatments (non-PDT group). In PDT group, 7 patients underwent PDT and unchanged systemic therapy (PDT-A group) and 8 patients underwent PDT with additional new line of systemic therapy on CRPC (PDT-B group). The Kaplan-Meier method was used to assess treatment outcomes.

Results: The prostate specific antigen (PSA) nadir was significantly lower in PDT group compare to non-PDT group (p=0.007). A 50% PSA decline and complete PSA decline were observed in 13 patients (86.7%) and 10 patients (66.7%) of PDT group and in 18 patients (72.0%) and 11 patients (44.0%) of non-PDT group, respectively. The PSA-progression free survival of PDT-B group was significantly longer than non-PDT group. The median time to failure of first-line systemic therapy on CRPC was 30.2 months in patients in PDT group and 14.9 months in non-PDT group (p=0.014). PDT-B group showed a significantly longer time to progression than non-PDT group (p=0.025). Minimal PDT-related adverse events were observed.

Conclusions: PDT can delay progression of disease and enhance treatment efficacy with acceptable tolerability in oligoprogressive CRPC.