Introduction

In prostate cancer, ductal adenocarcinoma is mixed with usual acinar adenocarcinoma. However, whether the proportion of ductal component affects oncologic outcomes is currently unknown. Here, we investigated whether the proportion of the ductal component predicts oncologic outcomes in ductal adenocarcinoma.

Methods

We retrospectively reviewed clinical data from 3,038 patients with prostate cancer who underwent radical prostatectomy at our institution between 2005 and 2014. We excluded patients who received neoadjuvant or adjuvant treatment. Patients were stratified based on the proportion of the ductal component. We compared the probability of biochemical recurrence between groups and investigated how the proportion of the ductal component influences biochemical recurrence using Kaplan-Meier estimates and Cox regression models, respectively.

Results

Of 2,648 patients, 101 (3.8%) had ductal adenocarcinoma and 2,547 (96.2%) had acinar adenocarcinoma. Biochemical recurrence-free survival for patients with ductal adenocarcinoma was significantly lower compared with those with acinar adenocarcinoma (p<0.001). When ductal cases were stratified by the proportion of the ductal component, biochemical recurrence-free survival for the high ductal component (≥ 30%) group was significantly lower compared that of the low ductal component (< 30%) group (p = 0.023). In univariate and multivariate Cox regression analyses, a high ductal component was a significant predictor of biochemical recurrence (hazard ratio 2.508, 95% confidence interval 1.133-5.552, p = 0.023).

Conclusions

The prognosis for ductal adenocarcinoma can be stratified by the proportion of the ductal component. This marker could potentially be used as a surrogate for poor prognosis or as a determinant for adjuvant therapy.

Funding

none