Le carcinome intracanalaire de la prostate : indication potentielle pour la radiothérapie adjuvante
Background: Intraductal carcinoma of the prostate (IDC-P) is a variant of prostate cancer (PC) that can be found amongst usual forms. Studies observed that IDC-P has a different biology and response pattern to treatments usually offered to patients with advanced disease. Treatment response for localised PC with IDC-P has never been studied. Objective: To test the impact of adjuvant radiotherapy (ART) in patients with localized PC and IDC-P. Methods: We performed a retrospective study of men with localized PC treated by radical prostatectomy (RP) with or without ART, from two centers (1993–2015). Exclusion criteria were the use of another type of treatment prior to BCR, and detectable PSA following RP or ART. Primary outcome was BCR. Patients were grouped by treatment (RPonly/RP+ART), IDC-P status, and presence of high-risk features (HRF: Grade Groups 4–5, positive margins, pT3 stage). Results: We reviewed 293 RP specimens (median follow-up 99 months, 63 BCR). Forty-eight patients (16.4%) were treated by RP+ART. Multivariate Cox regression for BCR indicated that IDC-P had the strongest impact compared to other HRF (HR=2.39, 95%CI:1.44-3.97), while ART reduced the risk of BCR (HR=0.38, 95%CI: 0.17-0.85). The protective effect of ART was superior in IDC-P[+] patients, when compared to IDC-P[–] patients. IDC-P[+] patients who did not receive ART had the worst BCR-free survival (log-rank P=0.023). Furthermore, IDC-P had the same impact on BCR-free survival as ≥1 HRF (log-rank P=0.955). Conclusion: Men with IDC-P who did not receive ART had the highest BCR rates, and IDC-P had the same impact as ≥1 HRF, which are often used as ART indications. Once validated, ART should be considered in patients with IDC-P.
Adjuvant radiotherapy Biochemical recurrence Intraductal carcinoma of the prostate Radical prostatectomy