PD13-12: Ductal and Intraductal Carcinoma of the Prostate at Radical Prostatectomy: Diagnostic Accuracy of Biopsy, MRI-Visibility, and Outcomes

Gaurav Pahouja*, Shalin Desai, Hiten D. Patel, Goran Rac, Teresa Cheng, Yudai Okabe, Alexander Gorbonos, Marcus L. Quek, Robert C. Flanigan, Maria M. Picken, Gopal N. Gupta, Maywood, IL

Introduction: Ductal adenocarcinoma (DA) and intraductal carcinoma (IDC) of the prostate are associated with higher stage disease at radical prostatectomy (RP), but diagnostic performance of biopsy or visibility of these lesions on multiparametric magnetic resonance imaging (MRI) is not well established. We evaluated diagnostic accuracy of biopsy, MRI-visibility, and outcomes for patients undergoing RP with DA/IDC histology compared to pure acinar adenocarcinoma (AA) of the prostate.

Methods: A retrospective cohort study of men receiving RP between 2014-2021 revealing any degree of AA, DA, or IDC on final pathology were included. Clinical variables, prostate biopsy, surgical data, final pathologic data, and biochemical recurrence (BCR) were analyzed. Student’s t-tests, Wilcoxson rank sum tests, and chi-squared tests were used as appropriate. Multivariable Cox proportional hazards regression evaluated BCR while multivariable logistic regression evaluated predictors of DA/IDC pathology.

Results: A total of 609 patients were included with 103 (16.9%) found to have DA (N=66) and/or IDC (N=72) histology, while 506 (83.1%) had pure AA. Compared to the patients with pure AA, patients with DA/IDC were older (p=0.001), had higher PSA (7.9 vs 6.4, p=0.01), and had higher grade group (GG) (p < 0.001) and cancer volume on biopsy. DA was noted on biopsy in 15 (2.5%) and IDC in 38 (6.2%) patients. The sensitivity and specificity of biopsy compared to RP for diagnosis of DA/IDC was 29.1% (16.7 DA, 27.8% IDC) and 96.6% (99.3% DA, 96.6% IDC), respectively. Positive and negative predictive values were 63.8% and 87.0%. DA/IDC patients had higher GG (p < 0.001), extraprostatic extension (72.8% vs 49.4%, p<0.001), lymphovascular invasion (p < 0.001), perineural invasion (p=0.03), and pathologic N stage (pN1 16.5% vs 4.9%, p<0.001) compared to pure AA patients. DA/IDC was associated with worse BCR (HR=1.77, (95% CI 1.08-2.90), p=0.02) after adjustment for age, PSA, RP GG, pT stage and positive surgical margins. Higher age (p=0.04), RP GG (p < 0.01), and pT3a (p=0.02) were associated with DA/IDC on RP. In a subset of 281 men receiving MRI, PI-RADS distribution was similar for patients with DA/IDC vs pure AA (90.7% vs 80.7% with PI-RADS 4-5 lesions, p=0.23).

Conclusions: Patients with DA/IDC histology had unfavorable pathologic features at RP with worse BCR independent of standard prognostic factors. Sensitivity of prostate biopsy was low for detection of DA/IDC histology at RP. Of the DA/IDC patients on RP that had MRI lesions, 90.7% were categorized as PI-RADS 4-5.

Source of Funding: None