Hypofractionated Volumetric Modulated Arc Radiotherapy with simultaneous Elective Nodal Irradiation is feasible in prostate cancer patients: A single institution experience

Abstract

Purpose: To assess feasibility, toxicity and biochemical relapse-free survival (b-RFS) for a group of organ confined (OC) Saudi prostate cancer patients treated by hypo-fractionated Volumetric Modulated Arc Radiation Therapy (VMAT) Simultaneous Integrated Boost (SIB) Elective Nodal Irradiation (ENI) whole pelvic radiotherapy (WPRT). Patients and methods: Between March 2009 and January 2014, 29 OC prostate cancer patients; median age 64 years, PS 0–1 were treated in King Faisal Specialist Hospital – Riyadh, Kingdom of Saudi Arabia using VMAT–SIB–ENI–WPRT, to a total dose of 70 Gy in 28 fractions. Twenty Four patients (83%) were treated with neo-adjuvant; concurrent androgen deprivation therapy (ADT). Median follow-up (FU) was 42 months (range: 18–72 months). Results: The 3-year actuarial b-RFS for low/intermediate and high risk groups were 100%, and 48%, respectively (p = 0.09) with a median FU period of 34 months (range: 14–53 months). Gleason Score (p = 0.02), and pretreatment PSA (p = 0.01) were predictive for biochemical failure on univariate analysis; with no observed prostate cancer-related deaths. Grade 2 acute/late GI and GU toxicities were 28%/0% and 17%/10% respectively with no reported grade 3/4 toxicities. Four (50%) out of the 8 patients with baseline partial potency, retained sexual function on long term follow-up. Conclusions: Hypo-fractionation dose escalation VMAT–SIB–ENI–WPRT using 2 arcs is a feasible technique for intermediate/high risk OC prostate cancer patients, with acceptable rates of acute/late toxicities, much favorable planning target volume (PTV) coverage, and shorter overall treatment time. Prospective randomized controlled trials are encouraged to confirm its equivalence to other fractionation schemes.

Keywords

• Prostate cancer
• Radiotherapy
• VMAT-intensity modulation
• Hypo-fractionation