Partial Breast Brachytherapy Less Effective Than Whole-Breast Irradiation in Older Patients: Presented at SABCS
By Alex Morrisson
SAN ANTONIO, Tex -- December 13, 2011 -- Brachytherapy for breast-conserving treatment appears to protect older women less than whole-breast irradiation, and has more adverse events, according to a study presented here at the 34th Annual San Antonio Breast Cancer Symposium (SABCS).
“We found that from 2000 to 2007, older women in the United States treated with brachytherapy experienced higher risks of losing the breast, postoperative infection, postoperative wound complications, breast pain, and fat necrosis than women treated with whole-breast irradiation,” said Benjamin Smith, MD, University of Texas M. D. Anderson Cancer Center, Houston, Texas, on December 7.
Dr. Smith and colleagues evaluated the Medicare claims of 123,244 women beneficiaries aged older than 66 years who were diagnosed with incident-invasive breast cancer between 2000 and 2007 and were treated with lumpectomy. Of that total, 7,291 women received brachytherapy.
Patients included in the study were treated with conservative surgery followed by accelerated partial-breast brachytherapy alone or whole-breast irradiation. The use of brachytherapy increased with time.
“We found that women treated with brachytherapy experience a 2-fold increased risk for subsequent mastectomy, indicating that women treated with brachytherapy were more likely to lose their breast after their initial breast-conserving therapy,” said Dr. Smith.
The risk of mastectomy was 4% in women who had brachytherapy and 2% in women who had standard whole-breast irradiation (P <.0001). In addition, the researchers found nearly a 2-fold increased risk for postoperative infection and noninfectious complications in women treated with brachytherapy.
Women who had brachytherapy had an incidence of 16% for infectious complications compared with 10% for women who had standard radiation (P <.05). About 16% of women with brachytherapy experienced noninfectious complications compared with 8% of the women who received whole-breast irradiation (P <.05).
“Women treated with brachytherapy were also more likely to experience radiation-related side effects, such as breast pain, fat necrosis, and rib fracture,” Dr. Smith said.
The researchers were surprised by the results. “I think that our results are plausible and consistent with the literature,” said Dr. Smith. “However, I did not expect that we would find a difference in outcomes between brachytherapy and whole-breast irradiation using this claims-based approach. Such an approach has never been used before to evaluate breast brachytherapy.”
Dr. Smith concluded that these data underscore the importance of waiting for “mature data” from randomised clinical trials before widespread adoption of breast brachytherapy.
[Presentation title: Partial Breast Brachytherapy Is Associated With Inferior Effectiveness and Increased Toxicity Compared With Whole-Breast Irradiation in Older Patients. Abstract S2-1]
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