Comedonecrosis within conventional prostatic adenocarcinoma vs. intraductal carcinoma of the prostate: their clinical significance is not comparable.

It remains controversial if Gleason grade should be assigned to intraductal carcinoma of the prostate (IDC-P) and if the prognostic value of comedonecrosis associated with IDC-P is equivalent to that in conventional/invasive prostatic adenocarcinoma (CPA) as a Gleason grade 5 pattern. We herein assessed radical prostatectomy findings and postoperative outcomes in 287 patients with CPA exhibiting any Gleason pattern 5. Our cases were divided into 4 cohorts according to the absence or presence of necrosis within CPA and/or IDC-P: Cohort-1) no necrosis in CPA/IDC-P (n = 179; 62.4%); Cohort-2) necrosis only in CPA (n = 25; 8.7%); Cohort-3) necrosis only in IDC-P (n = 62; 21.6%); and Cohort-4) necrosis in both CPA and IDC-P (n = 21; 7.3%). Univariate analysis revealed patients with necrosis only in IDC-P (P < .001) or both CPA and IDC-P (P = .001) had a higher risk of progression than those with necrosis only in CPA, while the prognosis was comparable between the no necrosis group vs. the CPA only necrosis group (P = .680) or the IDC-P only necrosis group vs. the CPA/IDC-P necrosis group (P = .715). In a subgroup of patients exhibiting IDC-P (n = 198), the presence of IDC-P necrosis was still associated with a significantly higher progression risk, compared with CPA necrosis only. In multivariable analysis, necrosis only in IDC-P (vs. necrosis only in CPA) showed significantly worse progression-free survival (HR = 3.193, P = .003). IDC-P necrosis, as an independent predictor, was thus found to be associated with significantly worse oncologic outcomes, compared with necrosis only in CPA, and might therefore be better not to be simply considered as a grade 5 pattern.