Clinical significance of IDC‐P as predictive factor after intensity‐modulated radiation therapy

Abstract

The clinical significance of intraductal carcinoma of the prostate (IDC‐P) in men with nonmetastatic prostate cancer (PCa) treated with high‐dose external‐beam radiation therapy remains unclear. The aim of this study was to evaluate the impact of IDC‐P in men who received intensity‐modulated radiation therapy (IMRT) for nonmetastatic PCa. All patients with high‐risk (H‐R) and very high–risk (VH‐R) PCa who received IMRT between September 2000 and December 2013 at our institution were analyzed retrospectively. We re‐reviewed biopsy cores for the presence of IDC‐P. Treatment consisted of IMRT (median: 78 Gy at 2 Gy per fraction) plus 6‐month neoadjuvant hormonal therapy (HT). In total, 154 consecutive patients with H‐R and VH‐R PCa were analyzed. Intraductal carcinoma of the prostate was present in 27.9% (n = 43). The median follow‐up period was 8.4 years. The 10‐year PCa‐specific survival, biochemical failure (BF), clinical failure, and castration‐resistant PCa rates were 90.0%, 47.8%, 27.5%, and 24.5% in patients with IDC‐P, and 96.6%, 32.6%, 10.8%, and 7.0% in those without IDC‐P, respectively (p = 0.12, 0.04, 0.0031, and 0.012, respectively). In multivariable analysis, IDC‐P was not identified as an independent predictive factor for BF (p = 0.26). The presence of IDC‐P was correlated with a significantly higher incidence of disease progression in men with H‐R and VH‐R PCa who received IMRT, although it was not identified as an independent predictive factor for BF. Further investigations are needed to determine the significance of IDC‐P as an independent predictive factor for survival outcomes.

Nomogram for predicting the overall survival and cancer-specific survival of patients with intraductal carcinoma of the prostate

“…The clinical importance of IDC-P in stereotactic body radiation (SBRT) for prostate cancer has been examined in various studies (Aizawa et al 2022 ; Tom et al 2019 ; Trinh et al 2019 ; Van der Kwast et al 2012 ) since 2012. The findings revealed a strong association between the presence of IDC-P and tumor metastasis, biochemical recurrence, and clinical recurrence following SBRT.…”

Recent insights on the clinical, pathological, and molecular features of intraductal carcinoma of the prostate

“…Although few reports have examined the clinical significance of IDC‐P in external‐beam radiation therapy, some reports 18,19 have shown that IDC‐P in biopsy samples from intermediate‐ or high‐risk prostate cancer patients is an independent prognostic factor for early biochemical recurrence and metastasis after radiation therapy. Kato et al 20 .…”

“…Some reports suggest that IDC‐P is resistant to radiotherapy, but others report that IDC‐P is not a prognostic factor in high‐ or very high‐risk patients undergoing intensity modulated radiation therapy with hormonal therapy 18,19,96 . Kato et al 97 .…”

“…[11][12][13][14][15] Furthermore, the presence of IDC-P is an independent prognostic factor for biochemical recurrence in patients receiving neoadjuvant hormonal therapy. 13,16,17 Although few reports have examined the clinical significance of IDC-P in external-beam radiation therapy, some reports 18,19 have shown that IDC-P in biopsy samples from intermediate-or high-risk prostate cancer patients is an independent prognostic factor for early biochemical recurrence and metastasis after radiation therapy. Kato et al 20 demonstrated that the presence of IDC-P was the only significant prognostic parameter for cancer-specific and overall survival among prognostic variables, such as age, prostate-specific antigen (PSA), T stage, and GS, for in de novo metastatic prostate cancer.…”

“…Although there is growing evidence linking IDC-P to aggressive disease, much is still unknown regarding the optimal treatment for IDC-P. 95 Some reports suggest that IDC-P is resistant to radiotherapy, but others report that IDC-P is not a prognostic factor in high-or very high-risk patients undergoing intensity modulated radiation therapy with hormonal therapy. 18,19,96 Kato et al 97 reported that in neoadjuvant ADT for localized highrisk prostate cancer, some IDC-P-positive cases on biopsy responded well to ADT and that IDC-P completely disappeared at RP, suggesting that the response of IDC-P to ADT may be heterogeneous.…”