Prognostic significance of the presence of intraductal carcinoma of the prostate and bone metastasis in needle biopsy for prostate carcinoma patients with Grade Group 5

Intraductal carcinoma of the prostate (IDC-P) and bone metastasis have been both identified to associate with unfavorable clinical outcome of the prostate carcinoma (PCa). Our objective is to examine whether IDC-P or bone metastasis at diagnostic biopsies was associated with each other and whether they were linked with overall survival (OS) and cancer specific survival (CSS) of Grade Group 5 patients. We retrospectively selected the prostate biopsy specimens of 120 PCa patients with Grade Group 5 from Qilu Hospital of Shandong University between 2012 and 2016. There were 12 patients with IDC-P only, 52 patients with bone metastasis only and 10 patients with both IDC-P and bone metastasis. Overall, there was a significant correlation between the presences of the IDC-P and bone metastasis (P = 0.003). Kaplan-Meier survival analysis demonstrated that the presence of IDC-P and bone metastasis in diagnostic needle biopsy both conferred unfavorable CSS of Grade Group 5 patients. In addition, the presence of bone metastasis was a poor predictor of OS. Univariate and multivariate analysis revealed that bone metastasis was an independent prognostic factor for OS of Grade Group 5 patients, but IDC-P failed to be significant for either OS or CSS. Collectively, our study suggested that bone metastasis is an important prognostic factor and superior than the presence of the IDC-P for PCa patients with Grade Group 5.