(UroToday.com) The 2024 South Central AUA annual meeting included the fellow essay podium presentation competition, featuring a presentation by Dr. Jorge Alcacio-Mendoza discussing whether PSMA PET SUVmax can predict high risk pathology and high risk disease. PSMA/PET is the most useful method for staging, given its ability to detect more lesions at lower PSAs, compared to other current imaging modalities. However, its ability to predict adverse pathologic features has not been thoroughly investigated.
The objective of this study presented at the 2024 South Central AUA annual meeting was to assess whether the SUVmax of the index lesion by PSMA/PET correlates with ISUP 4 and 5 in the prostatectomy specimen, and to determine if the SUVmax cutoff-point of the index lesion predicts high-risk pathology.
This was a single center prospective study that included any patient older than 18 years of age with non-metastatic prostate cancer in a referral center in Mexico from 2017-2024, of which patients underwent 18F-PSMA-11 PET, and had a radical prostatectomy within less than 12 weeks. A descriptive analysis of the SUVmax subrogates was performed, the cut-off point was determined by AUROC analysis, and a univariate logistic regression was performed for the prediction of high-risk pathology in the prostatectomy specimen.
Among 28 patients, the mean age was 67.4 ± 6.6 years of age, the mean PSA at diagnosis of 13.8 ± 8.0 ng/dl, and the mean PSA density of 0.11 ± 0.34. The mean SUVmax was 11.64 ± 8.38 and 17 (60.7%) of patients had a PRIMARY score of 4-5:
Overall, 8 (28.6%) of patients had an ISUP grade group 4-5 tumors, 42.8% were clinical T3 or greater, and 60.7% were NCCN high risk patients. At the time of radical prostatectomy, 39.3% were pathological ISUP grade group 4-5, and 53.6% were pathological T3 or greater:
The patients were divided into two groups: high risk (n = 11) versus low (n = 17) risk ISUP. There were significant differences in the SUVmax value of the index lesion, 17.14 versus 7.85 (p = 0.002) for high risk ISUP versus low risk ISUP:
Logistic regression analysis of SUVmax found that this model conferred an OR of 1.32 (1.06 – 1.64 p = 0.004) for high risk ISUP disease. Subsequently, an AUCROC curve was performed in which it was found that the SUVmax had a AUC of 86.4%, it’s best cutoff point was 9 (sensitivity 81.8%; specificity 88.2%, p = 0.001):
Subsequently, another logistic regression analysis with this cutoff point was performed, in which they found a classification accuracy of 80% with a PPV of 81.8% and a NPV of 88.2%, with an OR of 33.75 (4.03 – 282.6, p = 0.001).
For locally advanced versus not locally advanced disease, there were also significant differences in the SUVmax: 14.88 versus 6.27 (p = 0.002) for high risk versus low risk:
An AUCROC curve was performed to assess for locally advanced disease at the time of radical prostatectomy in which it was found that the SUVmax had a AUC of 90.4% and the best cutoff point was 8.9 (sensitivity 64.7%; specificity 100%, p < 0.001). Logistic regression analysis with this cutoff point was performed, in which they found a classification accuracy of 80% with a PPV of 92.3% and a NPV of 66.7%, with an OR of 24.0 (2.3 – 240.6, p = 0.007).
Dr. Alcacio-Mendoza concluded his presentation discussing whether PSMA PET SUVmax can predict high risk pathology and high risk disease with the following take-home points:
- Each one-unit increase in SUVmax is associated with:
- 32% greater risk of ISUP >= 4 pathology
- 22.8% greater risk of high risk disease features
- SUVmax cut point of 9 is associated with a:
- 33-fold higher risk of high risk pathology in radical prostatectomy specimens with a PPV of 81%
- 24-fold higher risk of high risk disease features in radical prostatectomy specimens with a PPV of 92.3%
- High risk ISUP is the single most important factor for biochemical recurrence
- The presence of these factors in the PSMA PET/CT should be discussed as it may influence the therapeutic decision, as patients with high risk features may benefit from a multimodal treatment approach or avoiding active surveillance
Presented by: Jorge Alcacio-Mendoza, MD, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 South Central American Urological Association (AUA) Annual Meeting, Colorado Springs, CO, Wed, Oct 30 – Sat, Nov 2, 2024.