International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationPatient Preferences and Physician Practice Patterns Regarding Breast Radiotherapy
Introduction
A host of clinical trials have established breast irradiation as an integral component of breast conservation therapy (BCT) (1). In modern practice, there are multiple methods of delivering breast radiotherapy (RT). Strategies differ in schedule, volume of tissue irradiated, and in the degree we understand their safety and efficacy (Fig. 1).
Conventionally fractionated whole breast irradiation (CF-WBI) targeting the entire breast with 1.80–2.00 Gy once daily is supported by more than a dozen Phase III trials (1). A lumpectomy cavity boost is commonly added to CF-WBI. Disadvantages of CF-WBI include the prolonged treatment course (5–7 weeks), delivery of ionizing radiation to sites within the breast remote from the lumpectomy bed, and radiation dose to surrounding normal structures including the lungs and heart.
Two general strategies have been employed in an attempt to improve on CF-WBI: shortening the total treatment time (hypofractionation) and irradiation of less than the entire breast (partial breast irradiation; PBI). Hypofractionated whole breast irradiation (HF-WBI) treats the entire breast for roughly 3 weeks at 2.66–3.20 Gy once daily. HF-WBI regimens have been tested in randomized trials against CF-WBI. These trials have shown no difference in disease-free survival, overall survival, or toxicity profile with significant follow-up 2, 3, 4, 5, 6.
PBI focuses radiation to a portion of the breast and accelerates the treatment duration. In the United States, typical PBI strategies deliver 10 fractions of 3.40–3.85 Gy twice daily over 5 days. Although Phase I-II trials of such PBI have been reported, quality randomized trials with long follow-up are limited (4). Currently, the National Surgical Adjuvant Breast and Bowel Project (NSABP) is conducting a Phase III trial (B-39) comparing CF-WBI with PBI. B-39 has not yet met accrual and mature results are not expected for years.
Adding to the complexity, there are multiple methods of delivering PBI, including balloon brachytherapy PBI (Balloon-PBI; e.g., MammoSite, Hologic Inc., Bedford, MA), three-dimensional (3D) conformal external beam PBI (3D-PBI), multicatheter brachytherapy PBI (Multi-Cath-PBI) and single fraction intraoperative PBI. Our survey project predates the recent publication of two large experiences with single fraction intraoperative PBI 7, 8.
With the advent of BCT, a considerable amount of data has been generated evaluating the decision between mastectomy and breast conservation 9, 10, 11, 12. The value of patient autonomy forms the bedrock of such research. Autonomy dictates that the patient should, and even must, make decisions about her treatment (13) (voluntas aegroti suprema lex: the will of the patient is the first law). Although much has been studied about what motivates patients and their physicians regarding the choice between mastectomy and breast conservation, we are unaware of any robust description of women’s preferences and physician practice patterns for the major options in breast radiotherapy. Our intent is to report survey data describing American breast radiation practice patterns in light of level I evidence and considering survey findings evaluating patient’s breast radiation preferences.
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Methods and Materials
Before commencement, this study was approved by the Institutional Review Boards of all governing institutions in accord with an assurance filed with and approved by the Department of Health and Human Services. The use of subjects in this research was compliant with the exemption requirements of 32 CFR Part 219 and AFI 40-402. The survey instruments are included in the Survey Appendix.
Demographics of physician respondents
More than three-fourths of respondents were in private practice and the majority described treating more than 50 new curative intent breast cancer patients each year. Table 1 details the physicians surveyed.
Physician practice patterns for radiation treatment modality
Physicians were asked how often they use the BCT irradiation regimens, including the various PBI techniques, in women who merit postlumpectomy radiation. Data are in Table 2. CF-WBI is offered by nearly all radiation oncologists (95% CI, 98.2–100.0%) and is used more than twice as often as
Discussion
Our research shows that the overwhelming majority of physicians deliver post-lumpectomy radiotherapy congruent with level I evidence. CF-WBI, as supported by a host of Phase III trials 1, 18, is delivered to more than two thirds of women by more than 80% of radiation oncologists.
The last decade has seen a radical change in breast cancer radiation. A large 1998–1999 national patterns of care study (19) found that 100% of women had received whole breast irradiation (WBI). No other breast RT
Conclusions
We recommend that physicians, professional organizations, and health care systems formally evaluate their breast radiation practice patterns to assure that the strategies they offer are congruent with best evidence. Providers should also renew their efforts to forward patient autonomy by having meaningful discussions about treatment options. This embodies the concept of comparative effectiveness which requires careful examination of all treatment related outcomes, costs, and unintended
Acknowledgments
This project was supported by funds from the Directorate for Modernization, Office of the Air Force Surgeon General.
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Disclaimer: The views and opinions expressed in this article are those of the authors and do not reflect official policy or position of the United States Air Force, Department of Defense, or US Government. Conflicts of Interest Notification David J. Hoopes, M.D. Actual or potential conflicts of interest do not exist David Kaziska, Ph.D. Actual or potential conflicts of interest do not exist Patrick Chapin, Ph.D. Actual or potential conflicts of interest do not exist Daniel Weed, M.D. Actual or potential conflicts of interest do not exist Benjamin D. Smith, M.D. Actual or potential conflicts of interest do not exist E. Ronald Hale, M.D., M.P.H. Actual or potential conflicts of interest do not exist. Peter A. Johnstone, M.D. Actual or potential conflicts of interest do not exist.