[68Ga]Ga-PSMA-11 PET/CT shows value in initial staging of prostate cancer

Data from a study recently published in Nuclear Medicine in Central and Eastern Europe showed a correlation between SUV_max values derived from [⁶⁸Ga]GA-PSMA-11 PET/CT scans and WHO/ISUP (World Health Organization/International Society of Urological Pathology) tumor grade group, suggesting that [⁶⁸Ga]GA-PSMA-11 may be a useful tool in the initial staging of prostate cancer.¹

“SUV_max values of intermediate and high-risk patients were significantly higher than those of low-risk patients, supporting the usage of [⁶⁸Ga]GA-PSMA-11 PET/CT in the initial staging of prostate cancer," concluded the authors.

For the study, investigators retrospectively assessed 34 patients who underwent [⁶⁸Ga]GA-PSMA-11 PET/CT for initial staging of prostate cancer. All patients included in the analysis had prostate cancer confirmed by histological assessment after biopsy and had Gleason score and PSA serum values obtained.

Overall, data from the study showed that 55.9% patients (n = 19) had extended disease detected by [⁶⁸Ga]GA-PSMA-11 PET/CT. Further, 34.4% of patients (n = 12) had infiltration of seminal vesicles, 32.4% of patients (n = 11) had metastases in the lymph nodes, and 20.6% of patients (n = 7) had bone metastases.

The investigators also observed a positive correlation between SUV_max values and WHO/ISUP group (Pearson's r = 0.557; P < .01), as well as between SUV_max values and PSA values (Pearson's r = 0.34; P < .05). No significant correlation was found between WHO/ISUP groups and PSA values (Pearson's r = 0.26).

Additionally, patients with high-risk disease (WHO/ISUP groups 3-5) were shown to have a significantly higher mean value of SUV_max compared with patients with low-risk disease (WHO/ISUP groups 1-2), with a mean value of 23.5 ± 13.2 for intermediate to high-risk disease vs 10.6 ± 5.4 for low-risk (P < 0.05). Broken up by individual grade groups, the mean SUV_max was 6.3 ± 1.8 for patients in WHO/ISUP group 1, 12.8 ± 5.3 in grade group 2, 19.3 ± 8.7 in grade group 3, 29.9 ± 16.9 in grade group 4, and 29.2 ± 15 in grade group 5.

On this finding, the authors note,¹ “The correlation between the Gleason score and SUV_max value can be explained by the increased intensity of PSMA expression as the tumor grade increases.”

In total, the study included 34 patients who underwent a [⁶⁸Ga]GA-PSMA-11 PET/CT scan between April 2021 and January 2023 at the Department of Nuclear Medicine at the University Hospital Centre Zagreb in Croatia. The mean age of participants was 69.7 ± 9.8 years. The mean PSA value was 33.8 ± 40.9 nmol/L (range, 2.2-232) among all patients in the study, and the mean SUV_max in prostate lesions was 19.5 ± 12.6.

In the study, 4 patients had WHO/ISUP grade group 1 (Gleason 3 + 3), 8 patients had grade group 2 (Gleason 4 + 3), 13 patients had grade group 3 (Gleason 4 + 3), 4 patients had grade group 4 (Gleason 4 + 4), and 4 patients had grade group 5 (Gleason 9 and 10).

Overall, the authors concluded,¹ “SUV_max values of intermediate and high-risk patients were significantly higher than those of low-risk patients, supporting the usage of [⁶⁸Ga]GA-PSMA-11 PET/CT in the initial staging of prostate cancer.”

Reference

1. Rogic I, Golubic AT, Zuvic M, et al. Clinical utility of [68Ga]Ga-PSMA-11 PET/CT in initial staging of patients with prostate cancer and importance of intraprostatic SUVmax values. Nucl Med Rev Cent East Eur. 2024;27(0):6-12. doi:10.5603/nmr.97424