Less Radiation Effective for Early Breast Cancer
Lower overall dose given in fewer fractions
THURSDAY, March 20 (HealthDay News) -- An overall lower radiation dose given in fewer fractions offers similar rates of tumor control and late adverse effects than the international standard for patients with early breast cancer, according to a report published online March 19 in The Lancet Oncology.
After primary surgery, John Yarnold, M.D., from Royal Marsden Hospital in Sutton, United Kingdom, and colleagues randomly assigned 2,236 women with early breast cancer to receive a total of 50 Gy of radiation in 25 fractions of 2 Gy, 41.6 Gy in 13 fractions of 3.2 Gy, or 39 Gy in 13 fractions of 3 Gy over five weeks.
After a median follow-up of 5.1 years, the researchers found that the local-regional tumor relapse rate was 3.6 percent after 50 Gy, 3.5 percent after 41.6 Gy, and 5.2 percent after 39 Gy. Based on photographs and patient self-assessments, there appeared to be lower rates of late adverse effects after 39 Gy than 50 Gy (hazard ratio 0.69 for late change in breast appearance).
"The data are consistent with the hypothesis that breast cancer and the dose-limiting normal tissues respond similarly to change in radiotherapy fraction size," Yarnold and colleagues conclude. "A lower total dose in a smaller number of fractions could offer similar rates of tumor control and normal tissue damage as the international standard fractionation schedule of 50 Gy in 25 fractions."
A contributor to the study is an employee of Eli Lilly.