Breast cancer is not a single disease but multiple ones, each carrying varying degrees of risk for endangering women’s health.
In recent years, many researchers have been focused on DCIS: ductal carcinoma in situ, the earliest stage of cancer that in most cases remains in the milk ducts and does not invade other tissues. (It’s considered stage 0.) About 20% of breast cancers diagnosed in the U.S. each year are DCIS. Many of them do not go on to become cancers—but a small percentage of so-called high grade DCIS do, and doctors only have crude ways to distinguish them.
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To be safe, physicians offer the vast majority of people with DCIS the same current standard treatment options: surgery, radiation, and often hormone therapy drugs.
That may not be the best path forward for everyone. In a new study published in JAMA, Dr. Shelley Hwang, vice chair of research in the department of surgery at Duke Cancer Institute, reports that certain women with DCIS who chose to have regular mammograms and careful monitoring of their lesions instead of surgery and radiation were not more likely to develop cancer over two years than those who opted for treatment.
“This study is another important step in helping women understand that not all DCIS is the same, even though we are treating them that way,” says Hwang, who has been conducting the study for seven years. “For the lowest risk DCIS like the ones in this study, surgery may not ultimately be needed.”
The trial, called Comparing an Operation to Monitoring with or without Endocrine Therapy (COMET), involved nearly 1,000 women diagnosed with low-risk DCIS (about half of U.S. cases are this type). Women diagnosed with higher risk DCIS—estrogen-negative DCIS, for example, or the kind that presents as a lump in the breast—were not included in the trial since they are not ideal candidates for avoiding surgery and radiation, says Hwang. Patients were followed for two years in a preliminary analysis; Hwang plans to continue following the women and comparing their cancer rates at five years and 10 years.
Women in the study were either assigned to receive surgery and radiation or to receive more frequent mammograms and monitoring. Women in both groups could elect to take hormone therapy. After two years, about 5.9% of women in the first group had developed cancer, while 4.2% of those in the second group did.
Interestingly, 44% of women assigned to receive surgery ultimately decided not to have the operation, and 14% of those assigned to receive active monitoring elected to have surgery to remove their lesions. Hwang’s team allowed the switches and conducted two statistical analyses of cancer rates—as they were assigned, and also by whichever treatment they chose, adjusting the analyses to account for the imbalance. Even with the switches, the active-monitoring group did not develop any more cancers than those getting surgery.
Hwang says longer-term follow up of at least five years will be needed before these results can justify any change in the way women with this diagnosis are treated, but the data are encouraging that less may be more for some women.
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That was the case for Laura Colletti, a 69-year-old North Carolina resident who was diagnosed with DCIS in 2014 after an annual mammogram. Her husband, a physician assistant, did extensive research online and learned that DCIS was considered stage 0 cancer, and they wondered whether aggressive treatment was necessary. They happened to make an appointment with Hwang.
Hwang explained that the current treatment for DCIS involved surgery to remove the lesions and radiation therapy. “I said to her, ‘What happens if I don’t want to do that?’” Colletti says.
Hwang had been wondering the same thing and told Colletti about the COMET study to answer that very question. While Colletti was ineligible to join the trial, she essentially received the same protocol as those who were assigned to active monitoring—getting mammograms every six months in the breast with DCIS and every year in the other breast, and receiving hormone therapy if she desired. “[My husband and I] were just thrilled when we heard we had options,” she says. She opted for active monitoring, and Hwang prescribed endocrine therapy.
That was 10 years ago. “Now I’m fine; I go every year for a mammogram just like everyone else,” she says. “It’s working out for me.”
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Breast experts are hopeful that more women will have the same experience. Many patients are already asking about less-invasive options that don’t increase their risk of recurrence. “I remember the first patient I discussed the trial with. She looked like she was going to cry, and she said ‘What? You will follow me?’ She was so delighted that she got up and hugged me,” says Dr. Henry Kuerer, professor and executive director of breast programs at MD Anderson Cancer Network, which was one of the nearly 100 study sites. “She did not want anybody to do surgery on her breasts, and after about 3.5 years, she’s doing great.”
More data will certainly be needed to confirm that women who choose active monitoring don’t go on to develop more cancers over time. Hwang is also planning to delve deeper into understanding what role endocrine therapy plays in that monitoring by comparing women who took the drugs to those who did not. “If we find among women in the active-monitoring group, that women who chose endocrine therapy have a lower likelihood of invasive progression than those who did not take endocrine therapy, then that tells us that endocrine therapy may be an important part of what active monitoring entails,” she says.
As encouraging as the data are, Dr. Larry Norton, medical director of the Evelyn H. Lauder Breast Center at Memorial Sloan Kettering Cancer Center, says the results still reveal an uncomfortably high rate of cancer development from DCIS. The findings, he says, are “good news with a caveat. Most people will say it’s good news that many women don’t need surgery. But the bad news is that there is still 5% invasive cancer after two years. I would like to see this very important study motivate more research into how we can do better, and not just how to do the same with less. We are going to have to in the future, and the present, change well-entrenched paradigms of care by doing courageous studies like this one.”
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Even while Hwang’s team continues to follow the patients, the data are encouraging enough that more breast experts may discuss them with patients diagnosed with DCIS. “I will give them the standard treatment guidelines, which include surgery and radiation, and I will also give them these results,” says Kuerer. “I will tell them, ‘Here are results of an early trial that have not become standard of care,’ but I would be willing to follow them in that way if they wanted.”
Kuerer says the findings could even open the door to more situations beyond DCIS in which women might be able to avoid invasive surgery. He is conducting a study to see if women with breast cancer that has spread to the lymph nodes can also avoid surgery; results aren’t in yet. “We are now in an era where we are testing the safety of completely eliminating the need for surgery for precancers such as DCIS and even aggressive invasive breast cancer with lymph node metastases,” he says. “This is exactly the personalization that I think our patients want. Not every cancer needs to have just one therapy for everyone.”
As screening methods become more sensitive and able to detect smaller, earlier forms of cancer, including DCIS, approaches such as active monitoring could become more relevant. “The patients in this trial are pioneers, and really trying to do something different for themselves as well as other patients who are going to have DCIS in the future,” says Hwang.
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