Improved outcomes with higher doses for salvage radiotherapy after prostatectomy

Area of Science:

• Oncology
• Radiation Oncology
• Urologic Oncology

Background:

• Salvage radiotherapy (RT) is a treatment option for patients experiencing biochemical recurrence after radical prostatectomy (RP).
• Optimizing RT dose is crucial for improving treatment efficacy and patient outcomes in this setting.

Purpose of the Study:

• To evaluate the impact of higher radiation doses on relapse-free survival in patients undergoing salvage RT after RP.
• To identify optimal radiation dose levels for improved biochemical relapse-free survival (bRFS).

Main Methods:

• A cohort of 122 patients with negative lymph nodes post-RP received salvage RT.
• Patients were treated with either 60 Gy (n=38) or 70 Gy (n=84) to the prostate bed.
• Kaplan-Meier and Cox multivariable analyses were used to assess factors predicting bRFS.

Main Results:

• A significant dose response was observed: 5-year bRFS rates were 25% for 60 Gy versus 58% for 70 Gy (p < 0.0001).
• Higher doses (70 Gy) independently predicted for improved bRFS (HR 0.48, p=0.012).
• Pre-RT PSA < 1 ng/mL and absence of seminal vesicle involvement also significantly improved bRFS.

Conclusions:

• A clinically significant dose response exists for salvage RT after prostatectomy, favoring higher doses.
• A prostate bed dose of 70 Gy is recommended to maximize disease-free survival in this patient population.