Stereotactic body radiotherapy harnesses improvements in technology to allow the completion of a course of external beam radiotherapy treatment for prostate cancer in the span of 4 to 5 treatment sessions.
Although mounting short-term data support this approach, long-term outcomes have been sparsely reported.
To assess long-term outcomes after stereotactic body radiotherapy for low-risk and intermediate-risk prostate cancer.
This cohort study analyzed individual patient data from 2142 men enrolled in 10 single-institution phase 2 trials and 2 multi-institutional phase 2 trials of stereotactic body radiotherapy for low-risk and intermediate-risk prostate cancer between January 1, 2000, and December 31, 2012. Statistical analysis was performed based on follow-up from January 1, 2013, to May 1, 2018.
The cumulative incidence of biochemical recurrence was estimated using a competing risk framework. Physician-scored genitourinary and gastrointestinal toxic event outcomes were defined per each individual study, generally by Radiation Therapy Oncology Group or Common Terminology Criteria for Adverse Events scoring systems. After central review, cumulative incidences of late grade 3 or higher toxic events were estimated using a Kaplan-Meier method.
A total of 2142 men (mean [SD] age, 67.9 [9.5] years) were eligible for analysis, of whom 1185 (55.3%) had low-risk disease, 692 (32.3%) had favorable intermediate-risk disease, and 265 (12.4%) had unfavorable intermediate-risk disease. The median follow-up period was 6.9 years (interquartile range, 4.9-8.1 years). Seven-year cumulative rates of biochemical recurrence were 4.5% (95% CI, 3.2%-5.8%) for low-risk disease, 8.6% (95% CI, 6.2%-11.0%) for favorable intermediate-risk disease, 14.9% (95% CI, 9.5%-20.2%) for unfavorable intermediate-risk disease, and 10.2% (95% CI, 8.0%-12.5%) for all intermediate-risk disease. The crude incidence of acute grade 3 or higher genitourinary toxic events was 0.60% (n = 13) and of gastrointestinal toxic events was 0.09% (n = 2), and the 7-year cumulative incidence of late grade 3 or higher genitourinary toxic events was 2.4% (95% CI, 1.8%-3.2%) and of late grade 3 or higher gastrointestinal toxic events was 0.4% (95% CI, 0.2%-0.8%).
In this study, stereotactic body radiotherapy for low-risk and intermediate-risk disease was associated with low rates of severe toxic events and high rates of biochemical control. These data suggest that stereotactic body radiotherapy is an appropriate definitive treatment modality for low-risk and intermediate-risk prostate cancer.
JAMA network open. 2019 Feb 01*** epublish ***
Amar U Kishan, Audrey Dang, Alan J Katz, Constantine A Mantz, Sean P Collins, Nima Aghdam, Fang-I Chu, Irving D Kaplan, Limor Appelbaum, Donald B Fuller, Robert M Meier, D Andrew Loblaw, Patrick Cheung, Huong T Pham, Narek Shaverdian, Naomi Jiang, Ye Yuan, Hilary Bagshaw, Nicolas Prionas, Mark K Buyyounouski, Daniel E Spratt, Patrick W Linson, Robert L Hong, Nicholas G Nickols, Michael L Steinberg, Patrick A Kupelian, Christopher R King
Department of Urology, University of California, Los Angeles., Department of Radiation Oncology, University of California, Los Angeles., Flushing Radiation Oncology Services, Flushing, New York., 21st Century Oncology, Fort Myers, Florida., Department of Radiation Oncology, Georgetown University, Washington, DC., Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts., Division of Genesis Healthcare Partners Inc, CyberKnife Centers of San Diego Inc, San Diego, California., Swedish Radiosurgery Center, Seattle, Washington., Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada., Section of Radiation Oncology, Virginia Mason Medical Center, Seattle, Washington., Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California., Department of Radiation Oncology, University of Michigan, Ann Arbor., Scripps Health, La Jolla, California., Virginia Hospital Center, Arlington.