Determinants of the combined use of external beam radiotherapy and brachytherapy for low-risk, clinically localized prostate cancer, "Beyond the Abstract," by Ruben G. W. Quek, PhD and Viraj A. Master, MD, PhD, FACS

BERKELEY, CA (UroToday.com) - Using guidelines published by the American Brachytherapy Society, the American Urological Association, and the National Comprehensive Cancer Network (NCCN), this is the first study to investigate the determinants of a specific case of guideline discordance where low-risk clinically localized prostate cancer patients were treated with external beam radiation therapy and brachytherapy.

By utilizing the linked Surveillance, Epidemiology and End Results (SEER)-Medicare database and the American Medical Association Physician Masterfile, our study found that overall, 6% of patients received combined therapy within six months after cancer diagnosis. However, geographic variations were found to be significantly associated with guideline-discordant combined radiation therapy. Particularly, our predicted probability model found that the likelihood of guideline-discordant combined radiation therapy on patients residing in Atlanta/ Rural Georgia and treated by non-institutional affiliated radiation oncologists was over 45%. This is compared with the less than 1% predicted probability of Utah patients receiving guideline-discordant combined radiation therapy by radiation oncologists across all practice affiliations.

Our study was published in light of the ongoing debate about prostate cancer over treatment, with its attendant implications for patient outcomes and U.S. health care expenditures. The clinical benefit of combined radiation therapy for low-risk clinically localized prostate cancer has yet to be proven; as shown in previous studies, such combined therapy increases the risks for genitourinary and gastrointestinal toxicity, decreases patients’ quality of life, and is considerably more expensive.

The issue of over treatment may be exacerbated with some urology groups that integrated intensity-modulated radiation therapy (IMRT), an expensive form of external beam radiation therapy, into their practice. Our study complements another recently published research[1] that showed an increased use of IMRT by self-referring urology-radiation oncology groups when compared to patients treated in National Comprehensive Cancer Network centers. Such NCCN centers are more likely to have physicians who have major medical school affiliation, whereas physicians who are part of urology-radiation oncology groups are more likely to practice in non-institutional settings (and may not have a major medical school affiliation). Another 2013 US Government Accountability Office’s[2] report also detailed the higher use of costly prostate cancer radiation treatment by self-referring providers.

More research is required to understand the between geographic variation and the within geographic variation found in our study across radiation oncologists treating in different types of practice settings. This will allow us to further understand the complex financial motives that might be at play, especially surrounding the self-referral loophole regarding radiation therapy, and how such reimbursement-associated financial incentives may lead to guideline discordant radiation therapy among prostate cancer patients. In addition, the retrospective Medicare claims database methodology used in this study could be leveraged on other clinical scenarios investigating the influence of physicians’ practice affiliations on eventual treatment selection.

References:

  1. http://www.nejm.org/doi/full/10.1056/NEJMsa1201141
  2. http://www.gao.gov/products/gao-13-525

Written by:
Ruben G. W. Quek, PhDa and Viraj A. Master, MD, PhD, FACSb as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

aStatistics and Evaluation Center, Intramural Research Department, American Cancer Society
Department of Health Policy and Management, Emory University

bWinship Cancer Institute
Department of Urology, Emory University

Determinants of the combined use of external beam radiotherapy and brachytherapy for low-risk, clinically localized prostate cancer - Abstract

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