Proton therapy for the management of localized prostate cancer: Long-term clinical outcomes at a comprehensive cancer center

Alan J Sosa; Howard D Thames; Jeremiah W Sanders; Seungtaek L Choi; Quynh-Nhu Nguyen; Henry Mok; X Ron Zhu; Shalin Shah; Lauren L Mayo; Karen E Hoffman; Chad Tang; Andrew K Lee; Thomas J Pugh; Reena Kudchadker; Steven J Frank

doi:10.1016/j.radonc.2023.109854

Proton therapy for the management of localized prostate cancer: Long-term clinical outcomes at a comprehensive cancer center

Radiother Oncol. 2023 Nov:188:109854. doi: 10.1016/j.radonc.2023.109854. Epub 2023 Aug 18.

Authors

Affiliations

¹ Departments of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
² Departments of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
³ Departments of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
⁴ Departments of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
⁵ Texas Center for Proton Therapy, Irving, TX, USA.
⁶ University of Colorado Denver, Aurora, CO, USA.

PMID: 37597805
DOI: 10.1016/j.radonc.2023.109854

Abstract

Background and purpose: Proton therapy (PT) has emerged as a standard-of-care treatment option for localized prostate cancer at our comprehensive cancer center. However, there are few large-scale analyses examining the long-term clinical outcomes. Therefore, this article aims to evaluate the long-term effectiveness and toxicity of PT in patients with localized prostate cancer.

Materials and methods: Review of 2772 patients treated from May 2006 through January 2020. Disease risk was stratified according to National Comprehensive Cancer Network guidelines as low [LR, n = 640]; favorable-intermediate [F-IR, n = 850]; unfavorable-intermediate [U-IR, n = 851]; high [HR, n = 315]; or very high [VHR, n = 116]. Biochemical failure and toxicity were analyzed using Kaplan-Meier estimates and multivariate models.

Results: The median patient age was 66 years; the median follow-up time was 7.0 years. Pelvic lymph node irradiation was prescribed to 28 patients (1%) (2 [0.2%] U-IR, 11 [3.5%] HR, and 15 [12.9%] VHR). The median dose was 78 Gy in 1.8-2.0 Gy(RBE) fractions. Freedom from biochemical relapse (FFBR) rates at 5 years and 10 years were 98.2% and 96.8% for the LR group; 98.3% and 93.6%, F-IR; 94.2% and 90.2%, U-IR; 94.3% and 85.2%, HR; and 86.1% and 68.5%, VHR. Two patients died of prostate cancer. Overall rates of late grade ≥ 3 GU and GI toxicity were 0.87% and 1.01%.

Conclusions: Proton therapy for localized prostate cancer demonstrated excellent clinical outcomes in this large cohort, even among higher-risk groups with historically poor outcomes despite aggressive therapy.

Keywords: Long Term Clinical Outcomes; Prostate cancer; Proton therapy; Radiation.