A new study has shown that in a cohort of older women with breast cancer, treatment with brachytherapy compared with whole breast irradiation was associated with a higher risk of subsequent mastectomy, more frequent infectious and noninfectious postoperative complications, but no difference in survival.
The findings — conducted by Grace L Smith of the University of Texas MD Anderson Cancer Center, Houston, and colleagues and published in JAMA — were drawn from a retrospective population-based cohort study of over 92,700 women aged 67 years or older. The women had incident invasive breast cancer, diagnosed between 2003 and 2007 and followed-up through 2008. After lumpectomy, 6,952 patients were treated with brachytherapy vs 85,783 with whole breast irradiation (WBI).
The researchers found that breast brachytherapy was associated with a higher risk of subsequent mastectomy, with a five-year cumulative incidence of 3.95 per cent in patients treated with brachytherapy vs 2.18 per cent in patients treated with WBI.
Breast brachytherapy was also associated with a higher risk of infectious and noninfectious postoperative complications, as well as a higher five-year incidence of breast pain.
Brachytherapy was also generally associated with higher risk of postradiation complications.
At five years, an absolute 1.77 per cent excess mastectomy risk in patients treated with brachytherapy compared with whole breast irradiation meant that, for every 56 women treated with breast brachytherapy, one woman was harmed with unnecessary mastectomy.
At one year, an absolute 10.64 per cent excess postoperative complication risk in women treated with brachytherapy meant that for every nine women treated with brachytherapy, one was harmed with an unnecessary postoperative complication.
“Potential public health implications of these findings are substantial, given the high incidence of breast cancer, along with the recent rapid increase in breast brachytherapy use. Although these results await validation in the prospective setting, they also prompt caution over widespread application of breast brachytherapy outside the study setting,” the researchers stated.
JAMA 2012 doi: 10.1001/jama.2012.3481