Patterns of care for omission of radiation therapy for elderly women with early-stage breast cancer receiving hormonal therapy.

Purpose: For well-selected elderly women who undergo segmental mastectomy for early-stage, estrogen receptor-positive breast cancer, hormonal therapy alone is emerging as an acceptable adjuvant therapy option since the initial publication of Cancer and Leukemia Group B 9343 study in 2004 and update in 2013. The rate of adoption of adjuvant hormonal therapy alone in lieu of radiation therapy (RT) and its associated patterns of care is not known in the United States and was the subject of this study.

Methods And Materials: We used the National Cancer Data Base to identify women aged ≥70 diagnosed with T1N0/T1Nx invasive breast cancer who underwent segmental mastectomy between 1998 and 2011. Because hormone receptor status was not specifically and reliably coded, only those who received hormonal therapy were included in this analysis. Univariate and multivariable exploratory analyses of factors associated with the use of RT were performed using SPSS, version 17.0.

Results: Of the 182,115 patients who met inclusion criteria, 97,530 (53.6%) patients underwent hormonal therapy and were included in the analysis. The RT utilization rate in this subset decreased with time from 84.9% in 1998 to 75.1% in 2011 (P< .001). Multivariable analysis revealed that the factors associated with decreased use of RT include (in order of association): older age, later year of diagnosis, greater comorbidity score, low grade, lack of insurance, treatment at academic facility, race, rural location, lower median income, and distance from facility.

Conclusions: This study assesses the patterns of care associated with the omission of RT in elderly women with early-stage breast cancer who received adjuvant hormonal therapy. Since the publication of major clinical trials, this strategy has been increasingly adopted. The strongest predictors of using this strategy included advanced patient age, high comorbidity score, and low-grade disease.