(UroToday.com) The 2023 ASTRO annual meeting included a session on patient-reported quality of life in prostate cancer, featuring a presentation by Dr. Priyamvada Maitre discussing late urinary toxicity and quality of life with curative radiotherapy for high-risk prostate cancer in the POP-RT randomized phase III trial. Whole pelvic radiotherapy showed better biochemical failure-free survival and metastasis-free survival than prostate-only radiotherapy in the phase III randomized POP-RT trial for high and very high-risk prostate cancer, albeit with higher RTOG grade 2 late urinary toxicity.1 The trial design for POP-RT is as follows:
At the 2023 ASTRO annual meeting, Dr. Maitre and colleagues reported a comprehensive look at updated long term, symptom-wise comparison and dose-effect relations from this trial:
Late urinary toxicity and cumulative severity of each symptom over the follow-up period were graded using CTCAE v5.0. Grade 2+ toxicities were compared between the trial arms by chi square test. Bladder dosimetry in 5-Gy increments (V5, V10, V15 through to V65Gy, V68Gy) from the trial database of approved radiotherapy plans, was compared for each urinary symptom and overall late grade 2+ toxicity by student t-test. Observed differences in dosimetric parameters were tested using multivariable logistic regression analysis, including age at diagnosis, known diabetes, tumor stage, trial arm, and prior transurethral resection of the prostate. Urinary quality of life scores were compared between arms using a generalized linear mixed model.
Combined late symptom-wise toxicity and dose-volume data were available for analysis for 193 of 224 patients. At a median follow-up of 75 months, the cumulative CTCAE grade 2+ late urinary toxicity remained higher with whole pelvic radiotherapy than prostate-only radiotherapy, though not statistically significant (36.5% vs 26.8%, p = 0.15). Grade 3 toxicity was low and similar in both arms:
Additionally, symptom-wise cumulative rates showed no significant difference between arms:
With regards to patient-reported urinary quality of life outcomes, there was no difference in quality of life scores of patients with grade 2+ versus < grade 2 urinary symptoms:
Potential reasons for this finding include low severe (grade 3) toxicity and grade 2 toxicity being manageable in the outpatient setting with oral medications. Assessing urinary quality of life by trial arm, the mean quality of life scores for the urinary domain of PR-25 were similar between arms:
Dosimetric comparison showed significantly higher bladder V5-V15 in patients with grade 2+ toxicity over those with < grade 2 urinary toxicity:
On symptom-wise analysis, V5-V40 range was significantly higher for the presence of dysuria, hematuria, and urgency. No significant differences were observed over higher dose range for any urinary symptom:
On multivariable analysis, no significant association was identifiable between bladder dosimetry and urinary symptoms, and urinary quality of life scores were similar between both arms for all the symptoms.
Dr. Maitre concluded her presentation by discussing late urinary toxicity and quality of life with curative radiotherapy for high-risk prostate cancer in the POP-RT randomized phase III trial with the following take-home messages:
- Compared to prostate-only radiotherapy, whole pelvic radiotherapy resulted in similar Grade 3 urinary toxicity of about 5% with about 10% higher cumulative grade 2+ urinary toxicity over long term follow up
- This difference was not reflected in patient-reported quality of life
- There was no difference by bladder dosimetry
- Whole pelvic radiotherapy particularly increased urgency and hematuria
- This may lead to higher adopting of pelvic radiotherapy in clinical practice
Presented by: Priyamvada Maitre, The Christie NHS Foundation Trust, Manchester, UK
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2023 American Society for Therapeutic Radiation Oncology (ASTRO) 65th Annual Meeting held in San Diego, CA between October 1st and 4th, 2023
References:
- Murthy, V, Maitre P, Kannan S, et al. Prostate-only versus whole-pelvic radiation therapy in high-risk and very high-risk prostate cancer (POP-RT): Outcomes from phase III randomized controlled trial. J Clin Oncol. 2021;39:1234-1242.