Prostate-Specific Membrane Antigen PET-Guided Intensification of Salvage Radiotherapy After Radical Prostatectomy: A...

Area of Science:

• Oncology
• Radiotherapy
• Nuclear Medicine

Background:

• Prostate-specific membrane antigen positron emission tomography (PSMA-PET) enhances detection of prostate cancer recurrence.
• Intensified radiotherapy (RT) guided by PSMA-PET may improve outcomes after radical prostatectomy (RP).

Purpose of the Study:

• To evaluate if PSMA-PET-guided intensified salvage RT (PSMAiSRT) improves failure-free survival (FFS) in patients with biochemical recurrence post-RP.
• To assess the impact of PSMAiSRT on cancer control and treatment-related toxicity.

Main Methods:

• A phase 2, randomized clinical trial (PSMAiSRT) involving 128 patients with biochemical recurrence after RP.
• Patients were randomized 1:1 to standard-of-care SRT or PSMA-PET/CT-guided intensified SRT.
• Primary endpoint was FFS, defined by PSA progression, radiological progression, initiation of next-line therapy, or death.

Main Results:

• PSMAiSRT significantly improved FFS (HR, 0.50; P=.04) and eugonadal FFS (HR, 0.45; P=.03) compared to standard SRT.
• The greatest benefit was observed in patients with PSA ≥0.3 ng/mL (HR, 0.17; P=.01).
• Fewer patients in the PSMAiSRT arm required next-line treatment (HR, 0.32; P=.04), with no significant differences in toxicity or quality of life.

Conclusions:

• PSMA-PET-guided intensification of SRT after RP demonstrates an isotoxic improvement in cancer control.
• This strategy offers a promising approach for managing recurrent prostate cancer.
• Further validation is ongoing in a phase 3 clinical trial.