Shorter radiation treatments for women with breast cancer may be more optimal than the currently prescribed standard dose, especially for women in early stages of the disease.
A new study published Sept. 19 in The Lancet Oncology showed that three weeks of high-dose radiation is just as effective as five weeks of lower-dose treatment, which is typically used.
"For most indications, a three-week course of postoperative radiotherapy can be recommended as standard of care for women with early breast cancer following breast conservation surgery or mastectomy," study researcher Dr. John Yarnold, a professor of clinical oncology at the Institute of Cancer Research in London, said to HealthDay.
The researchers found that giving a shorter treatment of radiation in higher doses, which is known as "hypofractionated radiation", is safe, cheaper and causes less damage to healthy surrounding tissue than longer-used methods.
"Three weeks of treatment is gentler on the healthy tissues without loss of anti-cancer effect, so it represents an improvement for women with early breast cancer," Yarnold explained.
The American Cancer Society estimates that 232,340 cases of invasive breast cancer will be diagnosed in women in 2013, in addition to 64,640 cases of non-invasive, early-form carcinoma in situ (CIS). About 39,620 women will die from the disease this year.
Researchers conducted two trials that used different radiation methods on 4,451 women treated for breast cancer at 35 different U.K. establishments. All the women had invasive breast cancer, and their cancers were completely removed before treatment.
The women were tracked for 10 years, and other variables including age, tumor severity, cancer stage, chemotherapy use or use of tumor bed boost (additional radiation therapy) were factored out from the researchers' analysis.
The first trial, START A, compared an international standard of 50 Gy given in 25 smaller doses over five weeks to a 41.6 Gy and 39 Gy program given in 13 treatments over five weeks. A Gy or "gray," is a unit of measurement of radiation.
The second trial, START B, used the same international standard but compared it to a 40 Gy treatment given in 15 doses of 2.67 Gy each, given over three weeks.
START A subjects had a similar cancer relapse rate no matter which treatment they received. Recurring cancer rates ranged from 6.3 percent to 8.8 percent of women in that trial.
However, START B subjects with the shorter, higher dose course had slightly lower relapse rates ranging from 4.3 percent to 5.5 percent. Importantly, they had less surrounding tissue damage than any other group. The long period of follow-up ensured that the higher dose method was safe for the women as well.
"The results support the continued use of 40 Gy in 15 fractions, which has already been adopted by most U.K. centers as the standard of care for women requiring adjuvant radiotherapy for invasive early breast cancer," the authors wrote.
As for whether other countries will adopt these lower standards, one German researcher expressed doubt to Medscape that one study would change established care guidelines.
"I doubt very much that these data will make a difference," said breast oncologist Dr. Sibylle Loibl of the University of Frankfurt in Germany