Low Acute Toxicity in Prostate Cancer Patients Treated With Hypofractionated External Beam Radiation Therapy and Single Fraction HDR Brachytherapy

Abstract

To evaluate the acute genitourinary (GU) and gastrointestinal (GI) toxicity for a scheme of external beam radiation therapy (EBRT) and high dose rate brachytherapy (HDR-BT) for prostate cancer patients. Between January 2010 and June 2013, we treated 114 patients with high risk prostate cancer (T≥3a, limited T3b and/or Gleason score>7) at our radiation institute. All patients received neo-adjuvant hormonal therapy. The EBRT delivered 58 Gy in 20 fractions to prostate and seminal vesicles with a helical intensity modulated radiation therapy technique. A PTV margin of 7 mm was used, and at the overlap of the PTV and the rectum/bladder a dose gradient of 95% to 85% of the prescribed dose was applied. Two weeks afterwards a single fraction of 10 Gy HDR-BT to prostate and the base of the seminal vesicles was given with an integrated boost to the dominant intraprostatic tumor region aiming for a dose of 15 Gy. The full brachytherapy procedure was performed in the operating theatre, on an outpatient basis. The radiation oncologist scored GU and GI toxicity based on patient questionnaires and follow-up visits. NCI-CTCAE v3.0. was used as scoring system. One hundred and twelve patients had a minimal follow-up of 3 months and were evaluable for acute toxicity. Two patients were lost to follow up. The majority of patients (87.5%) reported no or mild GU toxicity (grade 0-1). Thirteen patients (11.6%) developed grade 2 toxicity. Patients reported mainly urge and high frequency complaints, 5 patients had a urinary retention requiring temporary catheterization (< 6 weeks). One grade 3 toxicity was reported. The patient (0.9%) needed a dilatation of the urinary tract because of stenosis. Ninety-seven patients (86.6%) showed no GI toxicity. Fifteen patients (13.4%) showed grade 1 toxicity. Mainly slight blood loss, change of consistency and mild pain. One patient reported anal incontinence for which occasional use of pads was required Grade 2,3 and 4 toxicity was not reported. Our hypofractionated EBRT and HDR-BT scheme for high risk prostate cancer patients is a save procedure with low acute toxicity.