Long-Term Outcomes of Prospective Clinical Trial HDR-Brachytherapy Monotherapy in Single Day in Patients with Localized Prostate Cancer.

PURPOSE/OBJECTIVE(S): This prospective clinical trial to evaluated long-term outcomes associated with 2 fractions in a single day, one implant, high-dose-rate (HDR) brachytherapy as monotherapy for patients with localized prostate cancer. We report Genitourinary (GU) and gastrointestinal (GI) toxicity and Disease control.

MATERIALS/METHODS: Between November 2010 and Feb 2016 a total of 120 patients diagnosed with low/intermediate-risk localized prostate cancer were treated. The prescribed dose was 27 Gy in 2 fractions in a day using a single implant. 34 patients (28%) were intermediate-risk cancer. 38 patients (31,7%) received hormonal therapy. We measured the incidence of no biochemical evidence of disease (bNED) based on the Phoenix definition of failure (nadir prostate-specific antigen (PSA) + 2 ng/mL). GU and GI toxicity were evaluated by CTCAE v4.0 and sexual function were prospectively documented at each follow up visit.

RESULTS: With a median follow-up was 123 months (range 9-148) the actuarial rates of Local Control were 96%, Biochemical Control 93.4%, Distant Failure 3.3%, Disease-Free Survival 92.3 %, Metastasis-free survival 96.67% and Overall Survival was 86.7%. The cumulative incidence of acute grade (G) 1-2 GU toxicity was 20.8%, mainly frequency/urgency (10%), dysuria (10%), dribbling/hesitancy (0.8%). 3 patients required a Foley catheter during 1 week. No acute GI toxicities were recorded. Chronic G1-2 GU toxicities were 29 %, mainly dysuria (12.6%), urinary frequency/urgency (5.8%) and urinary Incontinence G2 (1.6%). 1 patient had G2 rectal bleeding and 2 patients had G3 GU toxicity requiring transurethral resection of bladder (TURB). 23.7% of patients without Hormonal therapy reported G1-2 sexual impotence after 2 years therapy.

CONCLUSION: With 10 years of follow-up, our prospective data are sufficiently mature to report on efficacy and toxicity outcomes, making a single implant, 2 fractions HDR-BT an attractive option for patients with localized low/intermediate-risk prostate cancer and be able to consider it a standard of care in this setting. To the best of our knowledge, this is the first report regarding single day HDR-BRT as monotherapy with a median follow-up of 10 years.