A study in the May 2 edition of JAMA reveals that older women with invasive breast cancer who were treated with brachytherapy after lumpectomy were more likely to develop complications and had a lower risk of long-term breast preservation than women who received whole-breast irradiation, however, there was no difference in overall survival.
The researchers write:
"Brachytherapy is a means of delivering radiation using an implanted radioactive source and has been used to treat various malignancies. In recent years, the use of breast brachytherapy after lumpectomy for early breast cancer has increased substantially despite a lack of randomized trial data comparing its effectiveness with standard whole-breast irradiation (WBI).
Because results of long-term randomized trials will not be reported for years, detailed analysis of clinical outcomes in a nonrandomized setting is warranted."
To date, at least 50,000 older women with breast cancer in the United States have undergone brachytherapy. According to the researchers, up to 10% of breast cancer patients are currently treated with this procedure.
Grace L. Smith, M.D., Ph.D., M.P.H., of the University of Texas MD Anderson Cancer Center, Houston, and her team conducted the retrospective population-based study in order to compare breast brachytherapy with WBI and to examine the risk of long-term breast preservation complications and survival among older Medicare patients diagnosed with invasive breast cancer.
The study included 92,735 women aged 67+ who were diagnosed with incident invasive breast cancer between 2003 and 2007. Patients received follow-up until 2008. After lumpectomy, 6,952 women underwent brachytherapy and 85,783 received WBI.
The team discovered that women who underwent breast brachytherapy were more likely to require a mastectomy in the future than patients treated with WBI (5-year cumulative incidence of 3.95% vs. 2.18%, respectively).
In addition, the researchers found patients treated with brachytherapy were also more likely to suffer from infectious and noninfectious postoperative complications. By 1 year, more patients treated with brachytherapy experience skin or soft tissue infection than those treated with WBI (1,126 patients [16.20%) vs. 8,860 [10.33%), respectively).
The researchers write:
"Similarly, by 1 year. 1,132 patients (16.25 percent) treated with brachytherapy experienced noninfectious postoperative, complications compared with 7,721 (9.00 percent) treated with WBI."
According to the researchers, women treated with brachytherapy generally had a higher risk of developing postradiation complications. They explain:
"Specifically, 5-year cumulative incidence of breast pain was 14.55 percent in patients treated with brachytherapy vs. 11.92 percent in patients treated with WBI; fat necrosis was 8.26 percent vs. 4.05 percent; and rib fracture was 4.53 percent vs. 3.62 percent."
The researchers found no considerable difference in the five-year overall survival rate; 87.66% patients treated with brachytherapy vs. 87.04% WBI.
At 5-years, an absolute 1.77% excess mastectomy risk in patients treated with brachytherapy compared with WBI meant that 1 woman underwent an unnecessary mastectomy for every 56 treated with breast brachytherapy, whilst the 1-year 10.64% excess postoperative risk of complication in women with brachytherapy meant that for every 9 women with brachytherapy, 1 woman suffered unnecessary postoperative complications.
The researchers conclude:
"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."
Written By Grace Rattue