Prostate-specific antigen doubling time predicts the efficacy of site-directed therapy for oligoprogressive...

Area of Science:

• Oncology
• Urology
• Medical Physics

Background:

• Site-directed therapies (SDTs) are emerging treatments for progressive lesions in oligometastatic prostate cancer.
• The efficacy of SDTs in oligoprogressive castration-resistant prostate cancer (CRPC) requires further investigation.
• Identifying prognostic factors for SDT in CRPC is crucial for patient selection and treatment planning.

Purpose of the Study:

• To evaluate the efficacy of SDT in patients with oligoprogressive CRPC.
• To identify pretreatment clinical variables and treatment procedures that predict treatment response and survival outcomes.
• To determine the prognostic value of prostate-specific antigen (PSA) doubling time in this patient cohort.

Main Methods:

• Retrospective review of 59 patients with oligoprogressive CRPC who received SDT between April 2014 and March 2022.
• Analysis of pretreatment clinical variables and treatment details.
• Evaluation of associations with >50% PSA response, progression-free survival (PFS), and time to next treatment (TTNT).

Main Results:

• A >50% PSA response was achieved in 66% of patients.
• Median PFS was 8.3 months and median TTNT was 9.9 months.
• Patients with a PSA doubling time ≥6 months demonstrated significantly higher >50% PSA response rates (87% vs. 45%), longer PFS (15.0 vs. 5.0 months), and longer TTNT (16.3 vs. 5.9 months) compared to those with PSA doubling time <6 months.

Conclusions:

• A PSA doubling time of ≥6 months independently predicts a favorable >50% PSA response, improved PFS, and longer TTNT in patients with oligoprogressive CRPC treated with SDT.
• PSA doubling time serves as a key prognostic indicator for SDT efficacy in oligoprogressive CRPC.
• SDT is a potentially effective treatment modality for select patients with oligoprogressive CRPC, particularly those with a longer PSA doubling time.