(S044) Patient-Reported Quality of Life After Stereotactic Body Radiotherapy (SBRT), Intensity-Modulated Radiotherapy (IMRT), and Brachytherapy

Joseph R. Evans, MD, PhD, Shuang Zhao, MSE, Stephanie Daignault, MS, Martin G. Sanda, MD, Jeff Michalski, MD, Howard M. Sandler, MD, Deborah A. Kuban, MD, Jay Ciezki, MD, Irving D. Kaplan, MD, Anthony L. Zietman, MD, Larry Hembroff, PhD, Felix Y. Feng, MD, Simeng Suy, PhD, Ted A. Skolarus, MD, P. William McLaughlin, MD, John T. Wei, MD, Rodney L. Dunn, MS, Steven E. Finkelstein, MD, Constantine A. Mantz, MD, Sean P. Collins, MD, PhD, Daniel A. Hamstra, MD, PhD; University of Michigan; Emory University; Washington University; Cedars-Sinai Medical Center; UT MD Anderson Cancer Center; Cleveland Clinic; Beth Israel Deaconess Medical Center; Massachusetts General Hospital; Michigan State University; Georgetown University; University of Michigan; VA Ann Arbor Healthcare System; 21st Century Oncology

BACKGROUND: Stereotactic body radiotherapy (SBRT) is gaining popularity as a radiotherapy option for localized prostate cancer that is less invasive than brachytherapy and less costly and time-intensive than intensity-modulated radiotherapy (IMRT). However, there are ongoing concerns about excess toxicity after SBRT compared with other radiotherapy options.

METHODS: We conducted a multi-institutional pooled cohort analysis of patient-reported quality of life (QoL) using the Expanded Prostate Cancer Index (EPIC-26) survey collected serially from baseline to 2 years. Men were treated with IMRT, brachytherapy, or SBRT at multiple institutions. Mean EPIC symptom domain scores were evaluated, as was the proportion of patients with a minimal clinically detectable difference (MCD) in each domain. Multivariate analyses were used to determine the independence and association of standard clinical variables and treatment type with domain scores at 2 years. Sensitivity analysis was performed for 12-Item Short Form Health Survey (SF-12) data, as a minor proportion of the SBRT patients were missing SF-12 data, and for year of IMRT treatment, as we suspected that IMRT technique may have evolved over time, which would be expected to decrease toxicity and reduce the impact on QoL.

RESULTS: Data were analyzed from 803 patients at baseline and from 645 patients at 2 years. Mean declines at 2 years across all patients were −1.9, −4.8, −4.9, and −13.3 points for the urinary obstructive, urinary incontinence, bowel, and sexual symptom domains, respectively. Based upon MCD, 29%, 20%, and 28% of all patients had detectable differences in urinary, bowel, and sexual domains, respectively, at 2 years. On multivariate analysis, brachytherapy had worse urinary irritation (−6.8 [−9.9, −3.6] points vs IMRT, P < .0001; −5.8 points [−9, −2.5] vs SBRT, P < .0001), but there were no differences in the bowel (P = .48), urinary incontinence (P = .21), or sexual domains (P = .18). QoL after SBRT was similar to IMRT for the urinary (P = .55, obstruction; P = .74, incontinence) and sexual domains (P = .57) but was associated with better bowel score (+6.7 [3.2, 10] vs IMRT, P < .0002; +5.5 [2.2, 8.8] vs brachytherapy, P = .001). We observed a positive association between SF-12 Mental and Physical component scores and 2-year domain scores for nearly all domains. Sensitivity analyses demonstrated a minimal effect of missing SF-12 data and no changes in 2-year domain scores with year of IMRT treatment.

CONCLUSIONS: There were slightly smaller declines in bowel QoL after SBRT and slightly larger declines in urinary QoL after brachytherapy. While QoL after SBRT, IMRT, or brachytherapy is largely similar and supports SBRT as a reasonable radiotherapy option for localized prostate cancer, a randomized comparison is needed for the strongest evidence.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org