Treatment analysis of patients diagnosed with intraductal carcinoma of the prostate (IDC-P) in the US from 2000 to 2018.

e17011 Background: Intraductal carcinoma of the prostate (IDC-P), considered both a distinct entity (found alone in ~3% of prostate biopsies) and negative prognostic factor of prostatic cancer (identified in ~20% of all patients with prostate cancer). IDC-P represents aggressive disease, and is associated with increased metastasis, recurrence, and prostate cancer-specific death. Given the mortality and rarity of this disease, we analyzed demographic and treatment trends of patients diagnosed with IDC-P in the US. Methods: A retrospective cohort study utilizing the Surveillance, Epidemiology, and End Results (SEER) database sponsored by the National Cancer Institute (NCI) was conducted for patients with a diagnosis of IDC-P between 2000 and 2018. Univariate, multivariate, and survival analyses were performed on demographic and treatment characteristics using 95% confidence intervals CI and a p-value < 0.05 indicating significance. Results: 1003 patients with complete follow-up and survival data were identified. Patients with local disease that underwent radical prostatectomy without radiotherapy (RT) had increased five-year overall survival (OS) compared those that only received RT (99% vs 75%; p<0.001); those with regional disease did not (p=0.617). No survival benefit was seen among patients that received RT in addition to radical prostatectomy compared to those treated with radical prostatectomy solely (p=0.770 for local disease and 0.909 for regional disease). Lymph node (LN) examination, performed in 33.1% of patients, yielded increased five-year OS compared to absence thereof (99% versus 73%; p<0.001). 45% of patients that had LN examined were found in a single SEER registry (California). The 2.7% of patients that received chemotherapy (CTX) saw no survival benefit in the setting of distant disease (n=14; 0% versus 78%, respectively; p<0.001). No difference was seen in five-year OS with respect to race (p=0.967) though single patients saw decreased OS compared to married ones (hazard ratio (HR)=0.83; p=0.050) and patients younger than 65 years saw increased survival (HR=0.89; p=0.002). On multivariate analysis, the interaction between stage, surgical treatment, and receipt of RT demonstrated a difference in five-year OS (p=0.020). Conclusions: This analysis demonstrates survival benefit with radical prostatectomy solely versus treatment with RT among patients with local IDC-P, and did not find benefit with CTX in patients with distant disease. The survival benefit found with LN examination may be a center- or region-specific outcome. Patient age and marital status may have implications for patient outcomes. Further investigation into specific treatments, socioeconomic factors, and disease surveillance measures for patients with prostate cancer is warranted.