(ChemotherapyAdvisor) – Despite Cancer and Leukemia Group B (CALGB) C9343 study results that found adjuvant radiation therapy provided minimal benefits for older women with breast cancer — prompting a change in clinical guidelines — few actual changes were observed in clinical practice, investigators reported in the Journal of Clinical Oncology online March 5.
“Particularly among women with limited life expectancy, the continued use of radiation therapy may impose health risks and an added burden to patients while providing no mortality benefit and a relatively small benefit in terms of locoregional recurrence,” the investigators wrote. “In addition, unnecessary radiation therapy represents a significant cost to Medicare.”
The Surveillance, Epidemiology, and End Results (SEER) Medicare data set was interrogated to assess use of adjuvant radiation therapy in 12,925 beneficiaries ≥70 years of age diagnosed with stage I breast cancer from 2001 to 2007, 76.5% of whom received radiation therapy. Mean age was 77.7 years.
Approximately 75% of women received radiation therapy following publication of the CALGB C9343 study results vs. 79% before the study publication (adjusted RR=0.97). Among patients with life expectancy <5 years, radiation therapy use decreased by 3.7%, from 44.4% pre-publication to 40.7% following publication. Among patients with life expectancy ≥10 years, radiation therapy use decreased by 3.0%, from 92.0% to 89.0%.