3177 - International Prostate Symptom Score Outcomes of Five Different Treatment Paradigms for Localized Prostate Cancer: A Single-Institution Experience

N. Gravbrot, B. Odei, S. B. Johnson, and J. D. Tward; Department of Radiation Oncology, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT

Purpose/Objective(s): For patients with localized prostate cancer (PC), several therapies, including surgery or radiation, can provide durable disease control. The International Prostate Symptom Score (IPSS) is an eight-question quality-of-life tool assessing lower urinary tract symptoms (LUTS) commonly utilized to monitor LUTS severity for PC patients. Here, we report our experience of IPSS outcomes for patients with PC treated by various paradigms. We hypothesize that IPSS scores will initially worsen but gradually improve across all radiation modalities, with greatest changes for those with baseline moderate LUTS and for those who undergo brachytherapy (BT). Materials/

Methods: We queried an IRB-approved prospective registry of patients with PC treated at the University of Utah from 2002 to 2023. Abstracted data included demographics, treatment details, and baseline and follow-up IPSS metrics. Patients were grouped according to treatment paradigm: (1) BT, (2) intensity-modulated radiation therapy (IMRT)/volumetric-modulated arc therapy (VMAT), (3) stereotactic body radiation therapy (SBRT), (4) BT+IMRT/VMAT, and (5) radical prostatectomy (RP). IPSS values before treatment and at routine post-treatment follow-up intervals (3-9 months) were evaluated, with a total of 24 months of follow-up. Proportional changes relative to baseline IPSS were reported over each 6-month interval and grouped according to mild (IPSS 0-7), moderate (IPSS 8-19), and severe (IPSS 20-35) LUTS.
Results: A total of 3,636 patients were included. 286 patients underwent BT (7.9%), 152 IMRT/VMAT (4.2%), 189 SBRT (5.2%), 195 BT+IMRT/VMAT (5.4%), and 2,814 RP (77.4%). At baseline, mild (IPSS 0-7), moderate (IPSS 8-19), and severe (IPSS 20-35) LUTS, respectively, was reported in 60%, 35%, and 5% of BT; 35%, 48%, and 17% IMRT/VMAT; 37%, 61%, and 2% SBRT; 59%, 36%, and 5% BT+IMRT/VMAT; and 44%, 43%, and 13% RP patients. Those with baseline moderate LUTS had a higher likelihood of progression to severe LUTS up to 6 months post-treatment (43-48%) compared to IMRT/VMAT (12%), SBRT (21%), and RP (6%) (p<0.001). At 24 months post-treatment, 12-22% still reported severe LUTS after BT+/-IMRT/VMAT, compared to 0%, 6%, and 3% for IMRT/VMAT, SBRT, and RP, respectively (p<0.001). Interestingly, at 24 months, 18-33% of BT+/-IMRT/VMAT patients improved to mild LUTS, similar to SBRT and IMRT/VMAT (18% and 23%, respectively). Patients with baseline mild LUTS were more likely to develop moderate-to-severe LUTS at 24 months with BT+IMRT/VMAT (61% vs. 18-46%). Few patients had severe LUTS at baseline, limiting this group’s analyses.
Conclusion: LUTS changes are common after treatment for PC. For those with baseline moderate LUTS, inclusion of BT is more likely to lead to clinical worsening. Up to a third of these patients may still improve to a level better than baseline irrespective of radiation modality. Patients with baseline mild LUTS are less likely to develop moderate or severe LUTS post-treatment if treated with SBRT or IMRT/VMAT.