18F-choline PET/CT driven salvage radiotherapy in prostate cancer patients: up-date analysis with 5-year median follow-up.

Salvage radiotherapy is generally considered as the standard treatment for biochemical relapse after surgery. Best results have been obtained with a PSA value < 0.5 ng/ml at relapse, while 60-66 Gy is deemed as standard total dose. Modern imaging, as dynamic-18F-choline PET/CT may identify site of recurrence, allowing dose escalation to a biological target volume. Hundred and fifty patients showed a local relapse at dynamic-18F-choline PET/CT at time of biochemical recurrence. High-dose salvage radiotherapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT positive area. Toxicity and relapse-free survival were recorded. Median PSA value at the beginning of salvage radiotherapy was 0.47 ng/ml (range 0.2-17.5 ng/ml). One-hundred and thirty nine patients (93%) completed salvage radiotherapy without interruptions. Acute gastrointestinal grade ≥ 2 toxicity was recorded in 13 patients (9%), acute genitourinary grade ≥ 2 toxicity in 2 patients (1.4%). One patient (0.7%) experienced late gastrointestinal grade 4 toxicity and 2 patients (1.4%) late acute genitourinary grade 3 toxicity. With a median follow-up of 63.5 months, 5 and 7-years relapse-free survival were 70% and 60.7%, respectively. With a median follow-up of 5 years the present study confirms that high-dose salvage radiotherapy to a biological target volume is feasible, with low rate of late toxicity and promising activity.