PV QA 1 - Poster Viewing Q&A 1
Purpose/Objective(s): Prostate high dose rate (HDR) brachytherapy (BT) can be used as monotherapy (MT) or as a boost with supplemental external beam radiotherapy (EBRT). There are limited data exploring patient-reported outcomes after HDR BT. We compared acute patient-reported and physician-graded toxicities of prostate HDR as MT and as a boost.
Materials/Methods: We performed a retrospective cohort study of men with prostate cancer who underwent HDR BT as either MT (13.5 Gy x 2) or a boost (13.5-15 Gy x 1 with 45 Gy supplemental EBRT). MT was used in all low risk patients and boost was used in all high risk patients. Intermediate risk patients received either based on clinical factors and MRI findings. The International Prostate Symptom Score (IPSS) and Expanded Prostate Cancer Index Composite Short Form (EPIC-26) were used to assess patient-reported urinary, bowel, and sexual function at baseline and at follow-up visits. Physician-graded gastrointestinal (GI) and genitourinary (GU) toxicity were assessed using Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Patient-reported toxicities were compared using Generalized Estimating Equations with an independent weight matrix to account for the correlation between multiple observations. Physician-graded toxicities were assessed using a generalized linear mixed effects model. A p-value <.05 was considered statistically significant.
Results: A total of 119 men met selection criteria. 87 (73%) men underwent HDR as MT and 32 (27%) underwent HDR as a boost (11 received pelvic EBRT). 22 patients received hormonal therapy. There were 24 low risk patients, 20 high risk patients, and 75 intermediate risk patients. Boost patients had a higher baseline IPSS score (median 9 vs. 5; p=.01) but no difference in baseline EPIC-26 scores. Median follow-up was 7.6 months. Post-treatment, for the overall group there was an increase in IPSS scores that was found to meet criteria for minimal clinically important difference (MCID) at 1 month but not 3 or 6 months. There was no difference in IPSS scores over time between boost and MT patients (p=.21) at any of these time points. MT patients had a greater decline in EPIC-26 urinary incontinence scores at 1 month (p=.01) but not at 3 months or 6 months. There was no difference between groups in EPIC-26 urinary irritative/obstructive scores through 3 months, but boost patients had a greater decline at 6 months (p=.04). There was no difference between groups in EPIC-26 bowel scores (p=.46) or sexual scores (p=.26) at any time point. No difference was found in the risk of grade ≥2 GU toxicity (p=.26) and GI toxicity was rare (n=2).
Conclusion: HDR MT patients have worse 1 month urinary incontinence compared to HDR boost patients, but worse 6 month urinary irritative/obstructive symptoms. Longer follow-up is needed to report on patient-reported late toxicity.
The asset you are trying to access is locked. Please enter your access key to unlock.