Early Versus Late Postoperative Radiotherapy in Patients With Prostate Cancer: Results of a Single-centre Retrospective Study

Background/Aim: A much-debated topic relating to patients at risk of local prostate cancer recurrence, but with post-operative leveIs of prostate-specific antigen (PSA) lower than 0.2 ng/ml, concerns the best timing of postoperative radiotherapy (RT), adjuvant or salvage? The present monocentric, retrospective study aimed to investigate the best PSA value at which to plan salvage RT for patients with recurrent prostate cancer. Patients and Methods: From January 2011 to December 2019, 158 patients were treated with adjuvant RT at Pisa University Hospital, whilst 91 patients underwent salvage RT. We grouped the patients treated with salvage RT using their PSA values at the time of salvage RT: PSA >0.5 ng/ml, PSA between 0 and 0.5 ng/ml, and PSA ≤0.2 ng/ml. The median follow-up was 63 months. Biochemical recurrence-free survival (BFS) measured from surgery was the primary endpoint. Results: Salvage RT led to shorter BFS compared to adjuvant RT considering the whole cohort of patients, with a hazard ratio of 3.195 (95% confidence interval=1.534-6.655, p=0.002). However, analysing only the group of patients with PSA ≤0.2 ng/ml at the time of salvage RT, salvage RT led to BFS similar to that achieved with adjuvant RT (p=0.35). Conclusion: Our results suggest that when scheduled for patients with a PSA ≤0.2 ng/ml, salvage RT results in equivalent biochemical control to that with adjuvant RT.