Metastasis-Directed Radiotherapy Achieves Nine-Month Disease Control in Oligoprogressive Prostate Cancer

A new study published in the Japanese Journal of Clinical Oncology suggests that metastasis-directed radiotherapy (MDRT) can provide meaningful disease control in patients with oligoprogressive castration-resistant prostate cancer (CRPC), potentially offering an opportunity to manage emerging resistant lesions without immediately escalating systemic treatment.

Researchers retrospectively analysed 43 patients treated between 2020 and 2024. All had oligoprogressive disease, characterised by progression at a limited number of metastatic sites. The primary endpoint was progression-free survival (PFS), with additional analyses evaluating PSA responses and outcomes following repeated radiotherapy.

The median PFS following initial MDRT was 9.0 months. A PSA reduction of at least 50% was achieved in 53% of patients, while 21% experienced a reduction of at least 90%. These findings indicate substantial biochemical activity alongside the observed period of disease control.

Interestingly, 13 patients (30%) underwent a second course of metastasis-directed radiotherapy after developing further oligoprogression. In this selected subgroup, median secondary progression-free survival (PFS2) was 14.0 months, suggesting that repeated local treatment may offer additional opportunities for disease control.

The researchers also identified two factors associated with earlier progression: previous exposure to androgen receptor signalling inhibitors in the castration-resistant setting (HR 4.53) and a PSA doubling time of 2.4 months or less (HR 3.24). No treatment-related adverse events of grade 3 or higher were observed.

Although the findings support the potential role of MDRT in carefully selected patients, the study was retrospective, involved a small cohort and lacked a control group.

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