Prospective study of salvage reirradiation for locally recurrent prostate cancer

There are no well-established re-treatment options for local recurrence after primary curative radiation therapy for prostate cancer (PCa), as prospective studies with long-term follow-up are lacking. A prospective study at the University of Bergen (Norway) evaluated focal salvage reirradiation with external-beam radiation therapy with a median follow-up of 7.2 years. The study included patients with biopsy-proven locally recurrent PCa at least 2 years after previous treatment. The treatment was 35 Gy in five fractions to the MRI-based target volume, and 6 months of androgen-deprivation therapy starting 3 months before radiation. Primary endpoint was biochemical recurrence-free survival (bRFS). The 2-year and 5-year bRFS rates were 81% and 58%, respectively. The five-year local recurrence-free survival, metastasis-free survival, and overall survival were 93%, 82%, and 87%, respectively. Two patients (5%) had durable grade 3 genitourinary toxicity, one combined with grade 3 gastrointestinal toxicity. Baseline factors predicting worse outcomes were PSA doubling time ≤ months, Gleason score > 7, and PSA nadir ≥ 0.1 ng/ml. The authors conclude that reirradiation with EBRT for locally recurrent PCa after primary curative radiation therapy was clinically feasible and had favorable outcomes with acceptable toxicity.