Typically, women who are diagnosed with advanced breast cancer that has metastasized (spread to other parts of the body) are given chemotherapy or hormone treatment rather than surgery. Many doctors believe that surgery offers no survival advantage for these patients, and may even worsen outcomes. But a recent Swiss study refutes that belief.
In the study, researchers used the Geneva Cancer Registry to analyze detailed information on 5,000 cases of invasive breast cancer that had been diagnosed since 1970. Of the 300 women who had metastatic disease, more than half (58%) did not have surgery for their primary breast cancer. The remaining 42% had either a mastectomy or some type of lesser surgery to remove the tumor.
The researchers found that the women who underwent surgery and had negative surgical margins-indicating that the surgeon had removed all of the cancer-were 40% more likely to be alive five years after their diagnosis than the women who did not have surgery.
This means that 27% of the women who had surgery and had negative margins were likely to still be alive five years after the operation.
In comparison, 16% of the women who had surgery but had positive margins were still alive five years later; and 12% of those who did not have surgery had a five-year survival rate.
The women whose cancer had spread to the bone (rather than the brain or the liver-other common sites) and had surgery were even more likely-80% more likely-to be alive five years later than those who did not have surgery.
"This is the first study to find such a marked improvement in survival at five years in women with metastatic breast cancer who have had surgical removal of the primary tumor," says study author Dr. Elisabetta Rapiti, senior researcher at the Geneva Cancer Registry at the University of Geneva. Another study found similar effects, but only followed-up the women for three years.
"These findings will be a surprise for many clinicians, as almost all national and international guidelines on the treatment of metastatic breast cancer either do not include surgery of the primary tumor, or even recommend against it," says Rapiti.
"Many clinicians, in fact, believe that in such [metastatic breast cancer] cases, surgery of the primary tumor can accelerate the progression of the metastases," she says.
For women, "This research already certainly reaffirms that [surgery] is not associated with a more rapid progression of the metastases or worse outcome," Rapiti adds.
More Studies Needed
Dr. Lori J. Goldstein, director of the breast evaluation center and leader of the breast cancer research program at Fox Chase Cancer Center in Philadelphia, doesn't think this retrospective study is enough to change standard treatment
"Retrospective studies are very useful in generating hypotheses," she says. However, what's needed are prospective studies, such as a randomized, controlled clinical trial, in which some women would be assigned to a surgery group and others to a treatment group, and then the results would be compared over time.
Rapiti agrees, saying that larger studies are needed, comparing those who have surgery with those who do not.
"It would be naive to assume surgery will benefit all women with metastatic disease," Goldstein says.