Single-dose Radiation in Early Breast Cancer

A single dose of radiotherapy delivered at the time of surgery may be an effective alternative to external beam radiation delivered over several weeks among selected patients with early breast cancer. Findings of this international Phase III trial were published in The Lancet.

Treatment for early-stage breast cancer often involves breast conserving surgery (lumpectomy), which may be followed by radiation therapy to decrease risk of recurrence. ?Two methods of delivering radiation include:

External beam radiation: High-energy rays are delivered to the breast from a machine outside the body over several weeks. Single dose intraoperative therapy: One dose of radiation is delivered at the time of surgery.

To compare the outcomes of a single dose of targeted radiotherapy delivered at the time of surgery with those of external beam radiation delivered over several weeks, researchers evaluated the two approaches in more than 2,000 women with early breast cancer. Participants were aged 45 or older. Approximately half the patients received a single dose of radiotherapy at the time of surgery, and approximately half received external beam radiation over several weeks. All women underwent breast-conserving surgery.

At four years outcomes of both approaches were similar: There were six local recurrences in the targeted radiation group compared with five in the external beam radiation group. As well, both groups experienced similar side effects and frequency of side effects.

It appears that among some patients with early breast cancer, a single dose of radiotherapy at the time of surgery may be an effective alternative to several weeks of external beam radiation therapy. The researchers caution, however, that these findings may not apply to all patients with early breast cancer, as this study evaluated only women who were 45 or older and considered appropriate candidates for breast-conserving surgery.? In addition, the follow-up remains too short to draw definitive conclusions. It will be important to see if there is any change in the results over time.

Reference: ?Vaidya JS, Joseph DJ, Tobias, JS, et al. Targeted intraoperative radiotherapy versus whole breast radiotherapy for breast cancer (TARGIT-A trial): an international, prospective, randomised, non-inferiority phase 3 trial. The Lancet [early online publication]. June 5, 2010.

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