To investigate the relationship between SUVmax on preoperative 68Ga-PSMA PET-CT and the clinicopathological characteristics of patients treated with radical prostatectomy.

The clinicopahtological data of patients evaluated with ⁶⁸Ga-PSMA PET-CT preoperatively and treated with radical prostatectomy between May 2016 and August 2019 were retrospectively reviewed. 31 patients with a mean age (63.1±4.9) and baseline PSA (72.71±173.15)ng/ml were enrolled. Their BMI mean (24.6±3.0)kg/m². Baseline testosterone of 14 patients was (4.72±1.64)ng/ml.Based on the Gleason scores related ISUP classification, all patients were classified into grade one in 5 cases, grade 2in 7 cases, grade 3 in 4 cases, grade 4 in 10 cases and grade 5 in 5 cases. The clinical classification included 6 cases in T_2a stage, 2 cases in T_2b stage, 17 cases in T_2c stage, 1 case in T_3a stage, 4 cases in T_3b stage and 1 case in T₄ stage. SUVmax was accessed by two independent professional nuclear medicine physicians. SUVmax was 12.49±9.38. SPSS 16.0 software was used to do statistic analysis.

The post-operative pathological results showed the surgical margin positive in 19 cases, negative in 12 cases, vascular positive in 5 cases, negative in 20 case, positive nerve invasion in 20 cases and negative in 11 cases. 2 patients were low risk, 7 patients were medium risk and 22 patients were high risk according to D′Amico classification. Based on the basis of PSA(≤10 or>10) and Gleason score(≤6 or>6), 6 patients were in group with low PSA and low Gleason score, 5 patients were low PSA and high Gleason score, 9 patients were high PSA and low Gleason score, 11 patients were high PSA and high Gleason score. SUVmax had a significant positive relationship with pathological ISUP(r=0.434, P=0.015) and SUVmax in patients with positive intravascular tumor emboli was significantly higher than those with negative intravascular tumor emboli(14.78±10.68 vs. 8.17±2.81, P=0.005). No significant correlation was found between SUVmax and baseline PSA, testosterone, pathologic T stage, surgical margin, nerve invasion, pelvic lymph node status as well as risk stratification. SUVmax could distinguish pathologic ISUP grade 5 with a maximum AUC 0.747 (P=0.033) and the sensitivity was 88.9%. The specificity was 77.3% when SUVmax≥11.34. SUVmax in patients with upgrading ISUP was significantly higher than that in patients with downgrading ISUP (16.01±5.40 vs. 4.98±2.11, P=0.007).

SUVmax measured on preoperative ⁶⁸Ga-PSMA PET-CT may have a clinical significance in predicting unfavorable pathological factors for patients treated with radical prostatectomy.

Prostatic neoplasms; Prostate cancer; Prostate-specific membrane antigen(PSMA); ⁶⁸Ga; Positron-emission tomography(PET-CT); Maximum standardized uptake value(SUVmax); Gleason score