Prognostic value of preoperative gallium-68 prostate-specific membrane antigen PET/computed tomography in predicting biochemical recurrence after radical prostatectomy.

[OBJECTIVES] This study evaluated the prognostic value of intraprostatic maximum standardized uptake value (SUVmax) on primary-staging gallium-68 prostate-specific membrane antigen (68Ga-PSMA) PET/computed tomography for predicting biochemical recurrence (BCR) and BCR-free survival after margin-negative radical prostatectomy, and explored an SUVmax cutoff.

[METHODS] This retrospective study included 78 men (2023-2024) who underwent preoperative 68Ga-PSMA PET/computed tomography, all reevaluated by an experienced nuclear medicine physician. BCR was defined as prostate-specific antigen at least 0.2 ng/ml on two consecutive tests. Follow up duration and time to recurrence were recorded. Mann-Whitney U, χ2, receiver operating characteristic, Kaplan-Meier, and Cox regression analyses were performed.

[RESULTS] BCR occurred in 21 of 78 patients (26.9%). Median follow up was 18 months, and median time to BCR was 12 months. Intraprostatic SUVmax was significantly higher in patients with BCR (P < 0.001). Receiver operating characteristic analysis showed an area under the curve of 0.798; the exploratory cutoff was 12.8, with 71.4% sensitivity and 84.2% specificity. Kaplan-Meier analysis showed significantly worse BCR-free survival in patients with SUVmax at least 12.8 (log-rank P < 0.001). In univariable Cox analysis, each 1-unit increase in SUVmax was associated with higher BCR risk (hazard ratio = 1.11, 95% confidence interval 1.06-1.16, P < 0.001), and this association remained significant in limited multivariable models.

[CONCLUSIONS] Intraprostatic SUVmax appears to be an exploratory imaging biomarker associated with postoperative BCR and shorter BCR-free survival rather than a stand-alone prognostic determinant. Larger prospective multicenter studies are needed for validation.