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

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.

To determine whether the IFPUP is associated with histological upgrading in specimens obtained from radical prostatectomy in patients with prostate cancer.

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.

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%.

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.