Investigating Histopathological Parameters and Immunohistochemical PSMA Expression Patterns in Prostate Cancer

By Robert Dillard - August 17, 2021

A study highlighted parameters that might impact accuracy of prostate-specific membrane antigen (PSMA)-PET for prostate carcinoma (PCa) detection. The results appeared in the European Journal of Nuclear Medicine and Molecular Imaging.

Researchers analyzed radical prostatectomy (RPE) specimens of 62 patients with preoperative 68Ga-PSMA-11-PET between 2016 and 2018. WHO/ISUP grade groups, growth pattern (expansive vs. infiltrative), tumor area and diameter as well as immunohistochemical PSMA heterogeneity, intensity and negative tumor area (PSMA%neg) were all correlated using spatially corresponding SUVmax on 68Ga-PSMA-11-PET.

According to the results, PSMA%neg, infiltrative growth pattern, smaller tumor area and diameter and WHO/ISUP grade group 2 significantly correlated with lower SUVmax values. A ROC curve analysis revealed 20% PSMA%neg as an optimal cutoff with the highest sensitivity and specificity (89% and 86%, AUC 0.923) for a negative PSMA-PET scan. A multiple logistic regression model revealed tumoural PSMA%neg (P < 0.01, OR = 9.629) and growth pattern (P = 0.0497, OR = 306.537) as significant predictors for a negative PSMA-PET scan.

The researchers concluded that “[the study describes] PSMA%neg, infiltrative growth pattern, smaller tumour size and WHO/ISUP grade group 2 as parameters associated with a lower 68Ga-PSMA-11 uptake in prostate cancer.”

They added that the findings “can serve as fundament for future biopsy-based biomarker development to enable an individualized, tumour-adapted imaging approach.”

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