Thousands of women undergo surgeries every year after an early breast cancer diagnosis. But could these treatments be unnecessary?
A new study from Canada found no difference in death outcomes between women who underwent a lumpectomy (tumor removal) or a mastectomy (breast removal) after an early breast cancer diagnosis and women who did not undergo treatment.
In this 20-year study from Women’s College Hospital and the University of Toronto Dalla Lana School of Public Health, 100,000 women were followed after a diagnosis of ductal carcinoma in situ (DCIS).
"What is important to note about this study is that it seems to validate our clinical suspicion that not all DCIS behaves in the same manner," said Roger A. Smith, MD, a general surgeon with Scott & White Healthcare in Round Rock, TX, in an interview with dailyRx News.
However, Dr. Smith said, "Until we know more about the most aggressive forms for DCIS (those most likely to evolve into invasive cancers), then we must continue to follow the current treatment guidelines, which in most cases involve surgical excision with or sometimes without radiotherapy."
Dr. Smith added, "It is important to realize that breast cancer treatment in 2015 is a continually evolving process, much like it has been for the past three decades. More studies are needed to validate any new treatment approaches for DCIS, as well as to help with stratification of the disease, but we can expect our current standards of treatment for DCIS to trend toward a more conservative approach in the next few years."
DCIS is an early-stage breast cancer that has not reached beyond the milk ducts.
"As we pushed to find smaller and smaller cancers, and targeted calcification instead of just masses, we began to identify DCIS more frequently," wrote Laura Esserman, MD, of the department of surgery at the University of California at San Francisco, in an editorial about this study. "Now DCIS accounts for approximately 20% to 25% of screen-detected breast cancers."
After 20 years, researchers found that the women who underwent a mastectomy or a lumpectomy had a 3.3 percent chance of death.
Women who didn't undergo surgery for DCIS had the same death rate.
"In medicine, we have a tendency to get too enthusiastic about a technique and overuse it,” said Otis W. Brawley, MD, the chief medical officer at the American Cancer Society, per The New York Times. "This has happened with the treatment of DCIS."
Researchers also found that women who had whole breasts removed had the same risk of cancer recurrence as women who had a lumpectomy.
According to study co-author Steven A. Narod, MD, a senior scientist at Women’s College Research Institute, fatal cases of DCIS are rare.
"I think the best way to treat DCIS is to do nothing," Dr. Narod told the Times.
But some disagree.
Monica Morrow, MD, the chief breast cancer surgeon at Memorial Sloan Kettering Cancer Center in New York City, told the Times that there is a chance that the fatal cases in this study were misdiagnosed, or that not enough of the tumors were removed during treatment.
According to Dr. Esserman, this study could be a precursor for developing other treatment strategies, such as hormone therapies.
"As we learn more, that gives us the courage to try something different," Dr. Esserman told the Times.
This study was published Aug. 20 in the journal JAMA Oncology.
No funding sources were disclosed.
Study author Dr. Iqbal disclosed funding from the Canadian Institute of Health Research. Dr. Narod holds a Canada Research Chair in Breast Cancer.