Three weeks of radiation therapy produced outcomes similar to five-week course

ASTRO 50th Annual Meeting

The results of a recent study showed that a three-week course of accelerated hypofractionated whole breast irradiation produced results similar to those found with five weeks of standard breast irradiation in patients who have undergone lumpectomy.

At the American Society for Therapeutic Radiology and Oncology 50th Annual Meeting, Timothy Whelan, MD, a radiation oncologist with the Juravinski Cancer Centre in Hamilton, Ontario, updated results first released in 2002.

Researchers at several sites in Ontario randomly assigned 1,234 women with invasive breast cancer to either 42.5 Gy in 16 fractions over 22 days (arm A; n=622) or the standard 50 Gy in 25 fractions over 35 days (arm B; n=612).

The risk for local recurrence after 10 years was 6.7% for arm B and 6.2% for arm A (95% CI, –3.5% to 2.5%). At 10 years, 71% of patients in arm B had “good” or “excellent” cosmetic outcome, compared with 70% for arm A (95% CI, –6.9% to 9.8%).

The researchers also reported that there were no differences for incidence of later radiation morbidity to the skin or subcutaneous tissue between the two arms.

“At 12-year median follow-up, accelerated hypofractionated whole breast irradiation demonstrated excellent local control, similar to that seen with standard breast irradiation,” Whelan said. “It was not associated with any increased long-term morbidity with respect to skin and soft tissue toxicity, breast cosmesis or non-cancer deaths.”

Whelan added that, while this radiation regimen is not appropriate for every woman — so far it has only been tested on women with early-stage, node-negative disease — accelerated hypofractionated whole breast irradiation is more convenient and less expensive for patients and insurers.

“In view of the evidence for continued efficacy and the absence of long-term toxicity, such an approach may now be considered an important option for women who wish to be treated in a shorter period of time.” – by Jason Harris

We now have long-term follow-up on a whole breast radiation scheme that shows not just equivalent local control, but that the cosmetic outcome isn’t compromised. Something that we as radiation oncologists continue to worry about is, when you increase that daily dose, how does it affect the long-term side effects? This study shows that even though patients are receiving higher daily doses of radiation, that’s not affecting cosmetic outcome and it’s not affecting local control.

– Meena S. Moran, MD

Assistant Professor, Department of Therapeutic Radiology, Yale School of Medicine

For more information:
Whelan T. #60. Presented at: the American Society for Therapeutic Radiology and Oncology’s 50th Annual Meeting; Sept. 21-25, 2008; Boston.