Older breast cancer patients had an increased rate of subsequent mastectomy if they received brachytherapy instead of external-beam radiation therapy (EBRT) after lumpectomy, but they fared better than patients who received no radiation, investigators reported.

Five years after initial treatment for early breast cancer, 2.8 percent of patients treated with brachytherapy had undergone mastectomy compared with 1.3% of patients who had EBRT. Both rates were lower than the mastectomy rate among women who had lumpectomy without adjuvant radiation therapy (4.7%).

Patients who met American Society of Radiation Oncology (ASTRO) suitability criteria for brachytherapy had mastectomy rates similar to those of patients who had EBRT, as reported online in the International Journal of Radiation Oncology Biology*Physics.

"The takeaway message to both physicians and older breast cancer patients is that, in general, all of these patients did well with very high likelihood of breast preservation," Benjamin Smith, MD, of the University of Texas MD Anderson Cancer Center in Houston, said in a statement.

"However, the likelihood of breast preservation was best with external-beam radiation, worst with no radiation, and in between with brachytherapy."

The results are consistent with those that Smith and colleagues have previously reported.

Brachytherapy to the lumpectomy cavity offers certain advantages over EBRT, including convenience and reduced exposure to radiation. Those advantages have fueled rapid growth in use of the treatment in recent years.

But some breast cancer specialists have remained unconvinced that breast brachytherapy leads to outcomes comparable to those of EBRT, particularly given the lack of patient-specific evidence to identify the most appropriate candidates.

To guide use of brachytherapy in clinical practice, ASTRO proposed suitability criteria. "Suitable" patients have low-risk characteristics and favorable local disease control. Patients who fall into the categories of "cautionary" have some high-risk characteristics associated with a reduced likelihood of favorable outcomes, and "unsuitable" patients do not meet criteria for breast brachytherapy.

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