Response of intraductal carcinoma of the prostate to androgen deprivation therapy predicts prostate cancer prognosis in radical prostatectomy patients

Background Intraductal carcinoma of the prostate (IDC-P) has a poor prognosis and is thought to be completely resistant to current therapies, including androgen deprivation therapy (ADT). However, to date, there are no data showing direct evidence of such resistance. Methods We retrospectively evaluated 145 patients with high-risk prostate cancer who underwent radical prostatectomy (RP) with neoadjuvant ADT between 1991 and 2005. All patient data were collected from slides prepared from needle biopsy (NB) samples of prostate tissue and RP specimens. Data were analyzed in terms of serum level of prostate specific antigen (PSA), Gleason score of NB samples, clinical T stage, the positive cancer core rate, maximum cancer extension rate, presence of Gleason pattern 5, and presence of IDC-P in both NB samples and RP specimens. Results The median initial PSA was 33.2 ng/mL (range, 2.4-296 ng/mL), and the median follow-up period was 109 months (range, 11-257 months). The preoperative median ADT period was 4 months (range, 1-20 months). IDC-P was present in 53 patients (37%) in NB samples and 65 (45%) in RP. The patients were divided into three groups based on the presence or absence of IDC-P in NB/RP samples (IDC-P-negative at biopsy: 92 cases, IDC-P-positive at biopsy with IDC-P disappearance: 15 cases, and IDC-P-positive at biopsy with IDC-P persistence: 38 cases). Overall, 28% of IDC-P-positive cases in NB samples showed the disappearance of IDC-P at RP. IDC-P persistence cases showed the poorest prognosis, while IDC-P disappearance cases had a similar prognosis to that of IDC-P-negative at biopsy cases in terms of disease-free survival, cancer-specific survival, and overall survival (P = .0018, P = .0087, and P = .0034, respectively). Conclusions Some cases with IDC-P responded to ADT and demonstrated favorable clinical outcomes similar to those of cases without IDC-P. These findings indicate that cases with IDC-P are heterogeneous.