Timing of Ga68-PSMA PETCT and patterns of recurrence after prostate radiotherapy: Implications for potential salvage

•Early Ga68-PSMA PETCT for rising PSA after prostate radiotherapy located majority of recurrences.•Early PSMA PETCT identified oligorecurrences potentially suitable for focal salvage therapy.•Recurrence identified in 75% patients at PSA 10 ng/mL respectively. Probability of detecting recurrence in Ga68-PSMA PETCT increased with higher PSA at scan (AUC = 0.82). Uptake was local in 20 (17.5%), oligometastatic in 39 (34.2%), and polymetastatic in 45 (39.5%) patients. Recurrence was potentially salvageable in 59/104 (56.7%) patients, being 67% at PSA ≤2 ng/mL but only 38% at PSA >10 ng/mL. Probability of recurrence being potentially salvageable declined with increasing PSA at scan (AUC = 0.68). Early Ga68-PSMA PETCT for rising PSA after definitive prostate radiotherapy detected majority of recurrent lesions and identified oligorecurrences amenable to focal salvage therapy.