Brachytherapy after lumpectomy is associated with greater morbidity and need for mastectomy compared with whole-breast radiation, according to a large retrospective study of Medicare claims for older women with early invasive breast cancer (JAMA. 2012;307:1827-1837). Five years after treatment, the rate of mastectomy was twice as high in women treated with brachytherapy versus whole-breast radiation. Both short- and long-term complications were significantly greater in women treated with brachytherapy in this review. The rate of 5-year overall survival was the same in both groups (ie, brachytherapy and whole-breast radiation): 87%.
Brachytherapy is becoming increasingly more common in the United States. An estimated 10% of women with invasive breast cancer are now receiving brachytherapy as an alternative to whole-breast irradiation following lumpectomy. The appeal of brachytherapy versus whole-breast radiation is its delivery of radiation to a smaller field as well as its shorter course of treatment. Whole-breast radiation typically involves daily treatments for 7 weeks.
The lead author was Grace L. Smith, MD, University of Texas MD Anderson Cancer Center in Houston. The study included 92,735 women aged 67 years or older with invasive breast cancer diagnosed between 2003 and 2007 and followed through 2008. Following lumpectomy, 85,783 women (92.5%) were treated with whole-breast radiation and 6952 (7.5%) underwent brachytherapy. A year later, brachytherapy led to infection of the skin or soft tissue in 16.20% of patients versus 10.33% of those treated with wholebreast radiation; furthermore, the rate of noninfectious complications was significantly greater in the brachytherapy group: 16.25% versus 9.0%.
At 5 years, the rates of other complications were also higher in the brachytherapy group compared with the whole-breast radiation group: breast pain, 14.55% versus 11.92%; fat necrosis, 8.26% versus 4.05%; and rib fracture, 4.53% versus 3.62%, respectively.
Limitations of the study include its retrospective nature, being based on Medicare claims data, and not taking into consideration improvements in technology since 2007 in delivering brachytherapy. Only a randomized controlled trial can definitively compare the 2 radiation techniques. An ongoing phase 3 randomized controlled trial sponsored by the National Surgical Adjuvant Breast and Bowel Project (NSABP) and the Radiation Therapy Oncology Group (RTOG) is currently comparing the safety and efficacy of brachytherapy versus wholebreast radiation, but results will not be available for several years.
“These results represent, to our knowledge, the first comprehensive, population- based study to directly compare the clinical outcomes associated with use of breast brachytherapy versus standard whole-breast radiation in older patients. Additional study is required to confirm the validity and generalizability of these findings,” wrote the authors.