Can the Gleason score be predicted in patients with prostate cancer? A dynamic contrast-enhanced MRI, (68)Ga-PSMA PET/CT, PSA, and PSA-density comparison study

Impact of intraprostatic PSMA maximum standardised uptake value following prostatectomy: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis to assess the relationship between intraprostatic maximum standardised uptake value (SUVmax) of the dominant prostatic lesion as measured on preoperative prostate-specific membrane antigen (PSMA) positron emission tomography (PET) with radical prostatectomy International Society of Urological Pathology (ISUP) Grade Group, pathological tumour (pT) staging, and biochemical recurrence (BCR).

METHODS

Prostate-specific membrane antigen PET may offer non-invasive assessment of histopathological and oncological outcomes before definitive treatment. SUVmax of the dominant lesion has been explored as a prognostic biomarker. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, we performed reviews of digital libraries and databases and retrieved studies reporting SUVmax quantified on PSMA PET computed tomography or magnetic resonance imaging and subsequent radical prostatectomy ISUP Grade Group, pT stage, and BCR. Quality assessment was performed using Quality Assessment of Diagnostic Accuracy Studies-2 and Prediction model Risk of Bias Assessment tools. Random effects meta-analysis and meta-regression by ISUP Grade Group and pT2 vs pT3/4 stage was performed. This study was registered on the International Prospective Register of Systematic Reviews (PROSPERO: CRD42023408170).

EVIDENCE SYNTHESIS

After removing duplicates, 23 studies were included for review. Pooled SUVmax (95% confidence interval [CI]) increased monotonically with advancing ISUP Grade Group, with ISUP 1: 5.8 (95% CI 3.9-7.7), through to ISUP 5: 17.3 (95% CI 13.1-21.5). For pT2 disease, pooled SUVmax: 9.7 (95% CI 7.8-11.5) increasing to 13.8 (95% CI 10.9-16.7) for pT3/4 disease. Substantial inconsistency was noted (I2 >50%) for all subgroups. This was not attenuated by restricting analysis only to studies using [68Ga]Ga-PSMA-11. Narrative synthesis of six papers reporting BCR showed increasing SUVmax was associated with reduced time to BCR.

CONCLUSION

Preoperative intraprostatic PSMA SUVmax increases monotonically with higher ISUP Grade Group and pathological tumour stage. Higher SUVmax is associated with reduced BCR-free survival. However, the use of single SUVmax thresholds for clinical decision making is not recommended as variability between studies is high.

Is the Ellipsoid Formula Reliable in Prostate MRI?

Our study seeks to study the accuracy of the ellipsoidal formula in prostate MRI of different sizes and to establish the limits of its use. The study included 31 patients with a well-visualized, intact prostatic capsule, excluding malignantly transformed prostates, as well as treated prostates, in which the contrast between the prostatic capsule and parenchyma is reduced. Each patient's prostatic volume was recalculated according to the ellipsoidal formula, and then it was compared with the prostatic volume calculated by the segmentation method. The two calculated volumes were similar, in some cases almost identical, with a slight tendency to underestimate prostate volume below 100cm3, in total in 18 cases, on average by 7.6% (+/-6%), overestimation of those with a volume over 100cm3, a total of 13 cases, on average by 3.2% (+/-2.5%), and of all, in 4 cases the difference between the two formulas was below 1%. There was no statistical difference between the two variables, Student's t-test p-value=0.039. With a precision of 92% (+/-6%), the ellipsoidal formula can be considered accurate when it is correctly performed, but if we take into account the importance that PSA density is starting to have in diagnosis, treatment and follow-up, the calculation of a secondary value through the segmentation method or high-precision software can be motivated when the ellipsoidal formula returns a value close to a threshold.