The expression of prostate-specific membrane antigen in intraductal carcinoma of the prostate

To investigate the immunohistochemical expression of prostate-specific membrane antigen (PSMA) and radiological parameters of [⁶⁸Ga]Ga-PSMA-11-PET/CT of intraductal carcinoma of the prostate (IDC-P). Seventy men with prostate cancer who had preoperative [⁶⁸Ga]Ga-PSMA-11 PET/CT scan and following radical prostatectomy were retrospectively included. Radiological parameters including maximal tumor diameter, mean standard uptake value (SUV_mean), and maximal standard uptake value (SUV_max) were derived from PET/CT images. Immunohistochemistry was used to determine the PSMA expression of IDC-P. The Mann-Whitney U test was performed for continuous variables and the chi-squared test for categorical variables. Logistic regression model was used for univariate analysis to compare the correlation between IDC-P and different preoperative variables. A total of 93 lesions were identified in 70 patients. Of these lesions, 21 (22.6%) in 20 patients (28.6%) were found to accompany IDC-P. The immune response score (IRS) of IDC-P lesions was significantly lower than that of prostate adenocarcinoma (P = 0.004).In multivariate analysis, SUV_mean was found to be significantly lower in patients/lesions with IDC-P (P = 0.011, OR: 0.797 [95% CI 0.669-0.948] in the per-patient analysis and P = 0.028, OR: 0.829 [95% CI0.701-0.980] in the per-lesion analysis, respectively). SUV_mean showed considerable AUC value of 0.71 (95% CI 0.589-0.839) in the per-patient analysis. Our results indicated lower histopathological PSMA expression and reduced [68Ga]Ga-PSMA-11 uptake in IDC-P compared to conventional prostate adenocarcinoma, suggesting that IDC-P may exhibit distinct biological features and could offer new insights for the radiological detection of intraductal carcinoma of the prostate in clinical practice.