The Use of Hormone Therapy Alone Versus Hormone Therapy and Radiation Therapy for Breast Cancer in Elderly Women: A Population-Based Study

Publication date: 15 July 2017
Source:International Journal of Radiation Oncology*Biology*Physics, Volume 98, Issue 4
Author(s): Alan M. Nichol, Elisa K. Chan, Sarah Lucas, Sally L. Smith, Lovedeep Gondara, Caroline Speers, Scott Tyldesley
PurposeThe Cancer and Leukemia Group B (CALGB) 9343 trial randomized elderly women with estrogen receptor–positive, stage 1 breast cancer to receive either hormone therapy (HT) or HT and radiation therapy (HT-RT) after lumpectomy and showed no difference in survival. After this publication, a practice guideline made HT alone a standard treatment option in British Columbia. The subsequent population-based pattern of practice was studied.Methods and MaterialsAll women aged 70 to 79 years, referred after lumpectomy from 1999 to 2009, with stage 1, estrogen receptor–positive breast cancer were identified. The use of adjuvant HT or HT-RT was evaluated in 2 eras: before (1999-2003) and after (2005-2009) the CALGB publication. The proportion receiving each treatment in these eras was determined. Kaplan-Meier analyses with Cox regression were used for survival endpoints. The Fine and Gray method was used with non–breast cancer death as a competing risk for event-free survival. The Charlson score was used to quantify comorbidity. Adherence was defined as dispensation of 80% of prescribed HT.ResultsHT-RT was used in 91% of patients before (n=319) and 89% of patients after (n=403) the CALGB publication (P=.4). In the HT-alone group, the rate of HT adherence was 75% at 1 year and 55% at 4 years. The 10-year locoregional recurrence–free survival rate was 98% with HT-RT and 90% with HT alone (P=.01), whereas the 10-year breast cancer–specific survival rate was 96% with HT-RT and 95% with HT alone (P=.2). Patients with grade 3 histology or lymphovascular invasion were more likely to have low event-free survival. On multivariate analysis, treatment type did not predict overall survival (P=.3).ConclusionsOur patient outcomes closely matched those of the CALGB trial, suggesting that its results are generalizable to a population of elderly breast cancer patients with typical HT adherence. The CALGB trial results, as well as the resulting practice guideline, did not change the use of adjuvant HT-RT in our population-based cancer program.



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