In a small study that observed women with BRCA gene mutations and different types of cancer and treatments, patients had two to four times greater risk of a cancer recurrence if they had only the cancerous lump removed instead of the whole breast.
However, their survival rates after 15 years appeared roughly similar, although this type of study cannot prove that one treatment is as good as another.
Results were presented Friday at a breast cancer conference in Barcelona.
Large studies have established that having a lumpectomy followed by radiation may be as effective as a mastectomy for women with early-stage breast cancers. However, it's not known if this is true for women with genes that predispose them to cancer. Lumpectomies also are sometimes followed by chemotherapy and hormone treatment such as tamoxifen depending on the size, type and spread of the cancer.
Dr. Lori Pierce, a professor of radiation oncology at the University of Michigan, and her colleagues observed 655 breast cancer patients in Australia, Israel, Spain and the United States, all of whom had genetic mutations that gave them a much higher chance of getting the disease. After 15 years, women who had a breast removed had about a 6 percent chance of a cancer relapse, compared with 24 percent of women who kept their breasts. If the latter group added chemotherapy, their risk dropped to about 12 percent.
The survival difference appeared much smaller: 87 percent of those who kept their breasts and 89 percent of those who had the more drastic surgery were alive after 15 years. The difference was not statistically significant, but so few deaths occurred in a study this size that it's hard to know if that would change with bigger or more rigorous research.