Intense Focal Peripheral Uptake Pattern on 18F‐PET/PSMA as a Predictor of Histological Upgrading in Prostate Cancer

BACKGROUND: Intraprostatic uptake patterns on 18F-PET/PSMA, such as those defined by the PRIMARY score, have been associated with clinically significant prostate cancer. However, the value of the peripheral focal intense uptake pattern (IFPUP), as a predictor of histologic upgrading after radical prostatectomy remains unclear. OBJECTIVE: To determine whether the IFPUP is associated with histological upgrading in specimens obtained from radical prostatectomy in patients with prostate cancer. METHODS: We performed a retrospective cohort study including patients with localized prostate cancer who underwent PET/PSMA prior to radical prostatectomy between 2022 and 2024. Clinical, imaging, and pathology data were collected. IFPUP was defined as SUVmax ≥ 11.4. Histologic upgrading was defined as an increase in ISUP grade from biopsy to prostatectomy. Associations were evaluated using multivariable logistic regression; diagnostic performance was assessed by AUROC, sensitivity, specificity, and predictive values. RESULTS: Thirty-four patients were included (median age 68 years, median PSA 12 ng/mL). Histologic upgrading occurred in 47.1% (16/34). IFPUP was observed in 33% and was significantly associated with upgrading (56% vs. 12%, p = 0.008). On multivariable analysis, IFPUP remained an independent predictor (OR 16.63, 95% CI 1.42-195.6, p = 0.025). Diagnostic performance of IFPUP included AUROC 0.722 (95% CI 0.574-0.870), sensitivity 56%, specificity 88%, positive predictive value 82%, and negative predictive value 68%. CONCLUSIONS: The presence of IFPUP on PET/PSMA is an independent predictor of histologic upgrading in localized prostate cancer. Its high specificity and positive predictive value suggest clinical utility as a complementary preoperative biomarker for risk stratification, warranting validation in larger cohorts.