Many studies have shown that women with early-stage breast cancer who have breast-conserving surgery followed by radiotherapy have similar survival rates as women who have a mastectomy, and those women are also spared the disfiguration of losing their breast. However, radiotherapy prolongs the length of time that women are treated for breast cancer, the treatment can be costly, radiotherapy facilities are not common in all areas, and there are some side effects to radiotherapy.
For these reasons, several studies have examined the consequences of omitting radiotherapy from the treatment regimen. Vincent Vinh-Hung, M.D., of the Oncology Center at Academic Hospital in Jette, Belgium, and colleagues performed a pooled analysis of 15 randomized clinical trials of women with early-stage breast cancer who underwent breast-conserving surgery alone or surgery followed by radiotherapy. They analyzed recurrence rates based on information from 9,422 women, and mortality information was available for 8,206 women.
The authors calculated that the women who received breast-conserving surgery alone were three times more likely to have a relapse than women who had breast-conserving surgery followed by radiotherapy. (In clinical trials that had 5 or more years of follow-up information, the relapse rate ranged from 0.4% to 2.1% per year for women who received breast-conserving surgery and radiotherapy, compared with 1.4% to 5.7% per year among women who only had surgery.) The authors also calculated that the omission of radiotherapy resulted in an 8.6% relative excess of deaths.
"The present study confirms that radiotherapy should not be omitted after breast-conserving surgery, except for medical contraindications such as systemic vascular disease or a previous history of irradiation," the authors conclude.
In an editorial, Katherine A. Vallis, M.D., Ph.D., and Ian F. Tannock, M.D., Ph.D., of Princess Margaret Hospital, Toronto, note that, although there may be a small subset of women with good prognostic factors who do not need to have radiotherapy after surgery, this analysis "reinforces the view that the large majority of patients undergoing breast-conserving surgery should also receive radiotherapy."
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