To do so, the authors recruited men with intermediate/high risk localized prostate cancer and randomized them to either to Arm A (HDR brachytherapy before EBRT) or Arm B (HDR brachytherapy after EBRT). Apart from timing, treatment administered in both arms was equivalent with an HDR boost of 15Gy, 46Gy in 23 fractions of EBRT, and neoadjuvant and adjuvant hormone therapy for up to two years. Patients were followed quarterly up to one year. The authors assessed Common Terminology Criteria for Adverse Events (CTCAE) scores for GU and GI toxicities. Further, International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF), and Functional Assessment of Cancer Therapy-Prostate (FACT-P) scores were collected to assess patient-reported quality of life outcomes.
Between 2015 and 2017, the authors randomized 100 patients of whom 88 had data available at the time of cut-off. The mean age was 69 years (standard deviation: 4.6). The two arms were well balanced with respect to age, Gleason score, tumor, node, metastasis (TNM), and clinical staging. Similarly, at baseline, the mean IPSS score was similar between both arms at baseline: Arm A (6.52) & Arm B (6.57).
At 12 months of follow-up, patients in both arms demonstrated mild worsening of symptoms in both arms, but no significant difference noticed between Arm A (8.02) and Arm B (8.14; p=0.55). While rates of Grade 1 and 2 GU toxicities were more frequent in Arm A (22.88% and 5.28%) compared to Arm B (19.36% and 2.64%), these differences weren’t significant. Similarly, rates of Grade 1 and 2 GI toxicities were more frequent in Arm A (23.76% and 5.28%) compared to Arm B (21.2% and 3.52%), but these differences were not significant. Additionally, there were no significant differences in IIEF or FACT-P scores at 12 months.
The authors concluded that the time of HDR brachytherapy (whether before or after EBRT) does not appear to affect rates of GI and GU related toxicities up to a year following treatment. The authors advocate a Phase III multicenter randomized controlled trial to validate their findings.
Presented by: Imtiaz Ahmed, MBBS, MRCP, FRCR, Consultant Urologist, Spire Healthcare, Clinical Lead in Oncology, Lead Cancer Clinician, Southend University NHS Trust, London, United Kingdom
Written by: Christopher J.D. Wallis, MD, PhD, Urologic Oncology Fellow, Vanderbilt University Medical Center, Nashville, Tennessee, Twitter: @WallisCJD during the 2021 ASCO Genitourinary Cancers Symposium (ASCO GU), February 11th to 13th, 2021