A groundbreaking study that compares surgical intervention to active monitoring for treating ductal carcinoma in situ (DCIS) indicates that women who take a careful approach in observing precancerous cells are not at a higher risk of developing breast cancer after two years than those who opt for surgery to eliminate them.
The preliminary findings from the Comparing an Operation to Monitoring with or without Endocrine Therapy (COMET) study imply that women and their healthcare providers might view active monitoring as a secure and less intensive strategy for managing low-risk DCIS. Previous beliefs suggested that numerous women diagnosed with DCIS may gain little from active treatment, but this notion had not been validated through clinical trials until now.
E. Shelley Hwang, M.D., a co-principal investigator from the Duke Cancer Institute and vice-chair in Duke’s Department of Surgery, will discuss these findings on December 12 at the San Antonio Breast Cancer Symposium. The study is also being published in the Journal of the American Medical Association (JAMA).
DCIS, often referred to as “stage-zero breast cancer” or “precancer,” is marked by the presence of abnormal cells within the milk ducts, and it doesn’t always advance to the invasive type of cancer that can spread beyond the breast. It is responsible for about one-fifth of all new breast cancer diagnoses in the United States, impacting over 50,000 women annually.
At present, the majority of women with DCIS undergo surgical treatment, with around one-third undergoing mastectomy, which can lead to lasting symptoms and changes in body image.
Active monitoring, in contrast to surgery and radiation, involves regular mammograms to detect any early changes.
“Many women question whether they really need to undergo surgery or radiation for DCIS,” said Hwang. “These early findings provide reassurance that active monitoring is a safe option in the short term and allows for early detection of cancers that arise during monitoring.”
For the COMET study, Hwang and her team, including co-principal investigator Ann Partridge, M.D., from Dana-Farber Cancer Institute, recruited nearly 1,000 women aged 40 and older.
After confirming DCIS through biopsy, study participants were randomly assigned to either the standard treatment, which includes surgery and radiation, or the alternative of active monitoring. Most women in both groups also received endocrine therapy to counter the estrogen hormone that often stimulates cancer growth.
After two years, the incidence of invasive cancer was 5.9% among women who had surgery, compared to just 4.2% in the active monitoring group. Hwang explained that the higher rate of invasive cancers in the surgery group might be linked to “upstaging,” where invasive cancer is discovered in patients diagnosed with DCIS during surgery.
“We observed fewer cancers diagnosed in the active monitoring group, and we believe that part of this is due to the hormone-blocking treatment many received,” Hwang elaborated. “Although opting for hormone therapy was optional in the study, more than 70% of women elected to combine active monitoring with endocrine therapy, indicating its potential significance for future women with DCIS.”
Both selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) have been shown to cut down the incidence of invasive cancer by around 50%, likely through mechanisms that either prevent progression of DCIS or reverse invasive cancer.
“These initial results are intriguing and could bring excitement for patients, but we must emphasize the necessity for further long-term follow-up,” stated Hwang. “If these findings persist, most patients with this low-risk condition may have the opportunity to avoid invasive treatments altogether. This would fundamentally change our approach to caring for these patients and our perspective on this illness.”
In a separate component of the research, Hwang and Partridge jointly led an additional study that assessed patient-reported outcomes from both groups involved in the COMET study.
“During the study, women provided feedback through surveys about their wellbeing over time,” commented Partridge, who serves as the interim chair of Medical Oncology at Dana-Farber Cancer Institute. “Fortunately, the overall quality of health-related life, levels of anxiety, depression, concerns, and symptom trends were similar, regardless of the treatment option chosen during the two years of follow-up.”
Alongside Hwang, the study authors from Duke include Thomas Lynch, Marc D. Ryser, Lars Grimm, Jeffrey Marks, Rachel Factor, and Yan Li.
The COMET study was backed by the Alliance Foundation Trials and received financial support from the Patient-Centered Outcomes Research Institute (PCS-1505-30497), the Breast Cancer Research Foundation, and Rising Tide Foundation.
