Main Session
Sep
29
PQA 06 - Genitourinary Cancer, Gynecological Cancer, and Health Care Access and Engagement
3294 - Determining the Effect of Prostate Size on the Quality-of-Life Outcomes for Prostate Cancer Patients Undergoing Definitive Radiotherapy
Presenter(s)
Allen Khodab, MD - University of Miami - Sylvester Cancer Center, Miami, FL
A. Khodab1, S. Kacker2, D. Song2, T. R. McNutt2, S. C. Greco2, C. Deville Jr2, A. N. Halthore3, and M. Goldstein2; 1University of South Carolina School of Medicine, Columbia, SC, 2Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 3Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Medicine, Washington, DC
Purpose/Objective(s):
Definitive radiotherapy (RT) is a standard-of-care option for localized prostate cancer across multiple risk groups. A common side effect is urinary obstruction, also typical of benign prostatic hyperplasia. While urinary quality of life (QOL) outcomes after RT are well described, limited data address how prostate size affects genitourinary (GU) side effects. This study examines whether pre-treatment prostate size influences long-term urinary QOL after definitive RT.Materials/Methods:
We retrospectively reviewed 868 patients with localized prostatic adenocarcinoma that were treated with definitive RT at the Johns Hopkins Hospital from 2004-2019. Pretreatment prostate volume was determined using clinical imaging, with high prostate volumes defined as >=100cc. Urinary symptoms were assessed using the International Prostate System Score (IPSS) at baseline, prior to radiotherapy, and at interval follow-up for a median of 4.0 years. Patients with fewer than two IPSS assessments and patients with no reported pre-radiation IPSS were excluded. Random effects panel regression models were used to analyze longitudinal IPSS, with baseline prostate volume-by-time interactions to assess whether initial prostate size influenced baseline IPSS and post-RT urinary symptom trends.Results:
Among 868 patients, mean prostate volume was 49.1 cc (range 2.2-192.8cc), with 52 (6.0%) having prostate volumes >100cc. Baseline IPSS scores (mean 9.4, range 0-35) were not significantly different between patient groups. Median peak and nadir IPSS scores were 15 and 4, respectively, with no statistically significant association of these measures with prostate volume. High prostate volume did not affect trends of IPSS over time. Comparing IPSS at baseline to at final follow-up, mean improvement was experienced by 59.6% of patients. Improvement was more common among patients with baseline high volume prostates (73.1% vs. 58.7%, p=0.04).Conclusion:
In this cohort, a large pre-treatment prostate volume defined as >100cc was not associated with significantly worse GU toxicity after definitive radiotherapy compared to patients with prostate volumes of <100cc, as measured by the change in IPSS after a median follow-up period of approximately 4 years. Notably, patients with glands >100 cc more frequently reported improvement in urinary symptoms by last follow-up, suggesting that patients with significantly enlarged prostate glands can be safely treated with definitive radiotherapy and may experience comparable or possibly greater symptom improvement. However, the small number of patients with volumes greater than 100 cc may potentially limit the power to detect differences and increase susceptibility to the effect of confounding variables. Ongoing analyses will evaluate prostatectomy patients stratified by prostate volume for comparison to the radiation cohort.