MP33-19: Intraductal Carcinoma of the Prostate in the Era of mpMRI-targeted Prostate Biopsies: Clinical, Pathologic and MRI Characteristics

Jonathan Fainberg*, Christine Chen, Johnson Chen, Adithya Balasubramanian, Christopher Barbieri, Leo Dreyfus, Beerinder Karir, Francesca Khani, Daniel Margolis, Timothy McClure, Himanshu Nagar, Brian Robinson, New York, NY

Introduction: Since 2018, there is increasing adoption of mpMRI to detect prostate cancer, particularly in the pre-biopsy setting. Recent studies showed that mpMRI is a sensitive tool for detecting cancers harboring intraductal carcinoma of the prostate (IDC-P). The presence of IDC-P has been associated with adverse pathological features and worse clinical outcomes. The goals of this study were to 1) determine frequency of IDC-P detected on biopsy in the mpMRI era and 2) assess the MRI and pathologic characteristics of biopsy proven IDC-P.

Methods: The pathology archives were retrospectively analyzed under an IRB-approved protocol.  All prostate biopsy and radical prostatectomy (RP) reports were reviewed for the presence or absence of IDC-P, Grade Group, pathological stage, presence of MRI targeted biopsies and MRI characteristics.  We reviewed cases from 2018-2020 (MRI biopsy years) and analyzed MRI features of all IDC-P proven biopsies.

Results: Between the years 2018-2020 86 patients had an mpMRI and IDC-P on prostate biopsy or prostatectomy specimen. Pathologic characteristics revealed: six (7%) GG1, thirty-two (37%) GG2, twenty-one (24%) GG3, three (4%) GG4, and twenty-four (28%) GG5. When IDC-P was present on biopsy, it appeared in 79% of the MRI targets, accounting for over half (52%) of all IDC-P cases detected on biopsy. 

In our cohort, 60 patients had IDC-P detected in the MRI target or in the systematic sextant concordant with an MRI lesion. 90% of these lesions were PIRADS 4 or 5 [25% PIRADS 4; 65% PIRADS 5]. 93% of the lesions were in the peripheral zone (PZ). Average lesion size was 1.97cm. Average ADC mean was 723.9 and 80% of lesions were positive for dynamic contrast enhancement (DCE). 93% of these lesions were >GG2.

Conclusions: These findings suggest that when IDC-P is present on biopsy, it is typically visible on pre-biopsy MRI as a targetable lesion that is PIRADS 4 or 5. These lesions tend to be large, positive for DCE and have low ADC scores. Cancers harboring IDC-P that are detected in the MRI era continue to be associated with aggressive radiologic and pathologic features. Further studies are needed to better characterize the mpMRI characteristics of IDC-P.

Source of Funding: None