Prostate-bed radiotherapy (RT) is an established treatment for men with biochemical recurrence of localized prostate cancer following radical prostatectomy (RP). Now, long-term data from the phase III GETUG-AFU 16 trial confirm that adding androgen-deprivation therapy (ADT) to RT further improves disease control.

In this trial, 743 men with biochemical evidence but no clinical evidence of disease relapse after RP received salvage prostate-bed RT with or without 6 months of ADT using goserelin. As reported in 2016, the primary end point of an improvement in 5-year biochemical and/or clinical progression-free survival (PFS) was met (80% with RT plus ADT versus 62% with RT alone; HR 0.50, 95% CI 0.38–0.66; P < 0.0001). The new data, from a post-hoc analysis, demonstrate that the PFS benefit of ADT was largely maintained at 10 years (64% versus 49%; HR 0.54, 95% CI 0.43–0.68; P < 0.0001), with a similar degree of benefit for both low-risk and high-risk disease subgroups.

The new data also showed a significant improvement in metastasis-free survival with ADT (75% versus 69% with RT alone; HR 0.73, 95% CI 0.54–0.98; P = 0.034), with a similar — but not statistically significant — degree of benefit in the low-risk and high-risk subgroups. However, 10-year overall survival was similar in both treatment arms (86% versus 85%). Notably, the authors estimated that 14 patients would need to be treated with ADT to prevent one metastasis event or death.

Importantly, short-term ADT had a good safety profile and did not increase the incidence of delayed serious adverse events. The frequency of late grade 3–4 urinary incontinence was ~5% in both groups.

These findings suggest that the choice of salvage therapy remains challenging, particularly considering advances in the treatment of later-stage disease; physician and patient preferences might be decisive.