Long Term Outcomes of Dose Escalated Pelvic Lymph Node Intensity Modulated Radiation Therapy (IMRT) with A Simultaneous Hypofractionated Boost to the Prostate For Very High Risk Adenocarcinoma of the Prostate, a Prospective Phase II Clinical Trial.

There remains limited data as to the feasibility, safety and efficacy of higher doses of elective radiation therapy (RT) to the pelvic lymph nodes in men with high risk prostate cancer. We conducted a phase II study to evaluate moderate dose escalation to the pelvic lymph nodes using a simultaneous integrated boost (SIB) to the prostate.

Patients were eligible with biopsy proven adenocarcinoma of the prostate, a calculated lymph node (LN) risk of at least 25%, Karnofsky Performance Scale ≥ 70, and no evidence of M1 disease. Acute and late toxicity were prospectively collected at each follow up using CTCAE version 4.0. The pelvic lymph nodes were treated to a dose of 56 Gy over 28 fractions with a SIB to the prostate to a total dose of 70 Gy over 28 fractions using IMRT.

30 patients were prospectively enrolled from October 2010 to August 2014. Median patient age was 70 years (57-83), pre-treatment PSA was 11.5 ng/mL (3.23-111.5), T stage was T2c (T1c-T3b), and Gleason score was 9 (6-9). CTCAE rate of any acute genitourinary (GU) and gastrointestinal (GI) toxicity were 55% and 44% respectively, there was 1 reported acute grade 3 GU and GI toxicity, both unrelated to protocol therapy. With a median follow-up of 6.4 years, biochemical failure free survival rates were 80.2%, mean biochemical progression free survival was 8.3 years (95% CI 7.2-9.4). The prostate cancer specific survival was 95.2%, mean prostate cancer specific survival was 8.7 years (95% CI 8.0-9.4). 5 year distant metastases free survival was 96%, mean was 8.2 years (95% CI 7.4-9.2). Medians were not reached.

In this single arm, small, prospective feasibility study, nodal RT dose escalation was safe, feasible and seemingly well tolerated. Rates of progression free survival are highly encouraging, in this population of predominately NCCN very high risk patients.

Practical radiation oncology. 2021 Apr 10 [Epub ahead of print]

William A Hall, Meena Bedi, Deepak Kilari, Kathryn A Bylow, John Burfeind, Candice Johnstone, Malika Siker, Adam Currey, William A See, Ariel Nelson, Scott Johnson, Michael Straza, Colleen Af Lawton

Froedtert and the Medical College of Wisconsin Department of Radiation Oncology. Electronic address: ., Froedtert and the Medical College of Wisconsin Department of Radiation Oncology., Froedtert and the Medical College of Wisconsin Department of Radiation Oncology; Froedtert and the Medical College of Wisconsin Department of Medical Oncology., Froedtert and the Medical College of Wisconsin Department of Medical Oncology., Froedtert and the Medical College of Wisconsin Department of Urology., Froedtert and the Medical College of Wisconsin Department of Radiation Oncology; Froedtert and the Medical College of Wisconsin Department of Medical Oncology; Froedtert and the Medical College of Wisconsin Department of Urology.