Toxicity after post-prostatectomy image-guided intensity-modulated radiotherapy using Australian guidelines.

Area of Science:

• Radiation Oncology
• Urologic Oncology
• Clinical Toxicity Assessment

Background:

• Post-prostatectomy radiotherapy (PPRT) is crucial for managing prostate cancer recurrence.
• Published data on late toxicity outcomes following image-guided intensity-modulated radiation therapy (IG-IMRT) for PPRT are limited.
• Fiducial marker implantation is used for precise IG-IMRT delivery.

Purpose of the Study:

• To evaluate single-institution toxicity outcomes after PPRT using IG-IMRT with fiducial markers.
• To assess acute and late genitourinary (GU), gastrointestinal (GI), and sexual toxicities.
• To compare toxicity rates with baseline and long-term outcomes.

Main Methods:

• Retrospective review of prospectively collected toxicity data from 293 men.
• Patients received 64-66 Gy IG-IMRT to the prostate bed between 2007 and 2015.
• Toxicity was assessed using established grading systems, with a median follow-up of 39 months.

Main Results:

• New acute grade ≥2 GU and GI toxicity occurred in 5.8% and 10.6% of patients, respectively.
• New late grade ≥2 GU, GI, and sexual toxicities were observed in 19.1%, 4.7%, and 20.2%.
• Four-year prevalence of grade ≥2 GU, GI, and sexual toxicities was 21.7%, 2.6%, and 17.4%, similar to or lower than baseline, with no grade ≥4 toxicities.

Conclusions:

• Post-prostatectomy IG-IMRT following Australian guidelines demonstrates tolerable acute and late toxicity.
• Long-term GU and GI toxicity prevalence remained stable, and sexual toxicity improved compared to baseline.
• Late toxicity rates associated with PPRT are comparable to or lower than those following definitive IG-IMRT, informing treatment decisions.