3369 - Early Patient-Reported Outcomes following Two-Fraction Prostate SBRT with and without Dominant Lesion Boost
Presenter(s)
V. Santos1, N. Aghdam2, C. Mendez3, A. Sanchez3, A. Katz4, A. Corcoran4, H. Lepor5, W. Huang5, D. R. Wise6, T. J. Carpenter3, A. Tong7, M. J. Zelefsky8, J. A. Haas3, and J. W. Lischalk1; 1Department of Radiation Oncology, Perlmutter Cancer Center at New York University Langone Hospital - Long Island, New York, NY, 2Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, MA, 3Department of Radiation Oncology, Perlmutter Cancer Center at New York University Langone Hospital - Long Island, Mineola, NY, 4Department of Urology, Perlmutter Cancer Center at New York University Langone Hospital - Long Island, Mineola, NY, 5Department of Urology, Perlmutter Cancer Center at New York University Grossman School of Medicine, New York, NY, 6Department of Medicine, Perlmutter Cancer Center at NYU Langone Medical Center, New York, NY, 7Department of Radiology, NYU Langone Health and New York University, Grossman School of Medicine, New York, NY, 8NYU Langone Health, New York, NY
Purpose/Objective(s): Two-fraction SBRT with dominant lesion simultaneous integrated boost (SIB) provides focal radiobiologic dose escalation in localized prostate cancer. In this Phase I/Ib, Single Arm Study of Two Fraction SBRT, we evaluated early patient-reported quality-of-life (QOL) outcomes comparing patients treated with and without SIB.
Materials/Methods: Twenty-two patients were analyzed, including 12 treated with SIB and 10 without SIB. Two fractions of SBRT were delivered to a total dose of 25 Gy in 2 weekly treatment fractions to the whole prostate with a 28 Gy SIB to the dominant lesion in patients with unfavorable intermediate risk disease or favorable intermediate risk with an elevated decipher score. EPIC urinary, bowel, and sexual domain scores were collected at baseline, 30 days posttreatment and subsequently every 3 to 4 months for 2 years. Median follow-up was 16 months.
Results:
Across both cohorts, (N=22), mean urinary scores declined from 87.5 at baseline to 85.9 at 4 months, with recovery to 83.8 at 12 months. Mean bowel scores declined from 93.0 at baseline to 91.3 at 4 months, remaining stable at 91.7 at 12 months. Sexual function demonstrated a transient decline from 41.8 at baseline to 38.7 at 4 months, with stabilization at 39.4 at 12 months. Across all domains, early changes were modest and without sustained clinically meaningful deterioration. In the non-SIB cohort (baseline N=10), urinary scores declined from 91.7 at baseline to 88.0 at 4 months, recovering to 89.8 at 1 year. Bowel scores declined from 94.8 to 88.3 at 4 months, recovering to 91.9 at 1 year. Sexual scores remained overall stable over time. In the SIB cohort (baseline N=12), urinary scores declined from 87.9 to 84.7 at 4 months and remained stable at 1 year (84.97). Bowel scores remained stable or improved over time (95.7 at baseline to 98.2 at 2 years). Sexual function declined transiently at 4 months (49.3 to 39.2) with recovery by 1 year. (49.15).Conclusion: At a median follow-up of 16 months, two-fraction SBRT demonstrates favorable patient-reported outcomes. The addition of a genomically stratified dominant lesion SIB does not appear to compromise urinary, bowel, or sexual quality of life.