Partial Breast Irradiation with Brachytherapy in Early Breast Cancer: Retrospective Analysis Looks at Trends and Guidelines


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Accelerated partial breast irradiation using brachytherapy (APBIb) as an alternative to whole-breast irradiation (WBI) after breast-conserving surgery has been rapidly adopted in the United States, but the majority of patients receiving APBIb may not be considered suitable for it.

A retrospective analysis of data from the Surveillance, Epidemiology, and End Results (SEER) database identified 138,815 patients who had received either APBIb or WBI between 2000 and 2007.1 The 3,576 women (2.6%) who had received APBIb were classified according to guidelines developed by the American Society for Radiation Oncology (ASTRO) in 2009. According to those guidelines, 32% would have been considered suitable for APBIb, 36.2% unsuitable, and 29.6% in the cautionary group.

Category Definitions

As explained by the investigators from Dana-Farber Cancer Institute/Brigham and Women’s Hospital and Harvard Medical School in Boston, “Patients were considered suitable if they met all of the following criteria: age 60 years and older; tumor 2 cm in diameter or less; T1 stage; [estrogen receptor (ER)] positive; unicentric tumor; invasive ductal, tubular, or mucinous histology; no pure DCIS; no [extensive intraductal component (EIC)]; pN0; and nodal surgery of either sentinel lymph node biopsy or axillary lymph node dissection. Patients were considered cautionary if they met any of the following criteria: age 50–59 years; tumor size 2.1–3 cm; T0 or T2 stage; ER negative; invasive lobular histology; pure [ductal carcinoma in situ (DCIS)] ≤ 3 cm; or EIC ≤ 3 cm. Patients were considered unsuitable for APBI if any of the following criteria were present: age < 50 years; tumor size > 3 cm; T3 or T4 stage; multicentric disease; pure DCIS > 3 cm; EIC > 3 cm; pN1, N2, or N3; or no nodal surgery performed.”

The investigators found a wide range of utilization patterns, including substantial racial and ethnic disparities. “[Nonwhite] patients were half as likely to receive APBIb compared with white patients regardless of appropriateness for this technique and regardless of whether they had DCIS or invasive breast cancer,” the researchers reported.

Specific geographic regions had higher APBIb use despite other patient and clinical factors. Women living farther from metropolitan areas and radiation facilities were less likely to get APBIb, even though the decreased overall treatment time for APBIb, 1 to 2 weeks vs 5 to 6 weeks for WBI, could potentially provide greater convenience and decreased travel time for the rural women. “The wide geographic disparity in use of APBIb suggests that unwarranted variation—practice variation not explained by illness, patient preference, or evidence-based medicine—may be present, which can have a profound impact on health care costs and patient outcomes,” the authors concluded.

Cautionary Note

3.3.42_quoue_b.jpgAn accompanying editorial noted that this study and two others concerning increased use of APBIb “raise an alarm that the care delivered to patients with early-stage breast cancer has evolved prematurely in relation to the results of large randomized trials examining the equivalency of APBI to WBI.2 As published guidelines, financial reimbursement, and information in the popular press regarding APBI change over time, it may become increasingly difficult to determine the exact motivation driving the disparate practices occurring nationally. Surgical and radiation oncologists will hopefully continue to be mindful during discussions with patients to inform them about the quality of the published data thus far available concerning patient outcomes following treatment with APBI. Although population-based studies allow us to reflect on changes in patterns of practice, we are still left eagerly awaiting the results of large randomized trials that compare patient outcomes with WBI vs APBI.” ■

References

1. Hattangadi JA, et al: Accelerated partial breast irradiation using brachytherapy for breast cancer: Patterns in utilization and guideline concordance. J Natl Cancer Inst 104:29-41, 2012.

2. Shaitelman S: Sounding a warning bell? Documentation of the increased utilization of accelerated partial breast irradiation. J Natl Cancer Inst 104:5-7, 2012.



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