SABCS 2024: BCRF-Supported COMET Trial Reports Promising Early Results on Active Monitoring for DCIS

With critical BCRF funding, trial investigators are now conducting long-term follow-up to further validate these potentially practice-changing findings

Women diagnosed with ductal carcinoma in situ (DCIS) who opt for active monitoring instead of surgery and radiation are no more likely to be diagnosed with breast cancer after two years, reported BCRF investigator Dr. E. Shelley Hwang in a session at the San Antonio Breast Cancer Symposium (SABCS) today. 

DCIS is the earliest stage of breast cancer and is marked by the presence of abnormal cells in the milk ducts. Because it hasn’t infiltrated nearby breast tissue, it’s considered a potential precursor to invasive breast cancer (hence why it’s called stage 0). More than 50,000 women are diagnosed with DCIS each year, with the vast majority undergoing surgery (and, in some cases, radiation), to treat the condition. Nearly all cases of DCIS can be cured.

While surgery is the standard of care for DCIS, not all cases will progress to invasive breast cancer, leading to potential overtreatment for some women with low-risk DCIS. When DCIS is diagnosed, it receives a nuclear grade that helps doctors determine how likely it is to become invasive. The lower the grade, the lower the risk. In this study, low-risk was defined as grades 1 and 2.

Active monitoring for DCIS—in which a patient undergoes more frequent mammograms to monitor any suspicious areas of the breast—is a potential alternative to surgery and radiation. Investigators have long hypothesized that active monitoring could be a safe option for some women but to date, few trials have put these options head-to-head.

The BCRF-supported Comparing an Operation to Monitoring with or without Endocrine Therapy (COMET) trial is the first trial in the U.S. to test active monitoring as an alternative to surgery and radiation. Led by co-principal investigators Drs. Hwang and Ann Partridge, a fellow BCRF investigator, COMET enrolled 995 women 40 or over who were randomized to receive standard-of-care surgery and radiation or active monitoring. Most also received optional anti-estrogen hormone therapy to reduce their risk of breast cancer.

At SABCS and in a paper published today in the Journal of the American Medical Association, Dr. Hwang and colleagues reported that 5.2 percent of patients who underwent surgery developed invasive breast cancer within two years, while 4.2 percent of the patients who received active monitoring did. (The investigators noted that the increased rate of invasive breast cancer in the surgery group was likely due to the disease being identified during surgery.)

“This marks the first time that active monitoring for DCIS has been rigorously put to the test,” Dr. Hwang said. “Our findings are an early indicator that for some women with low-risk DCIS, active monitoring could be a safe, non-inferior alternative to surgery and radiation.”

Dr. Hwang noted that while these early results are important, the trial needs to follow patients for years to confirm these findings and validate the safety of active monitoring. Only then could this potentially change how low-risk DCIS is treated. However, support for long-term follow-up can be difficult to secure from traditional funding sources. That’s where BCRF has stepped in. The Foundation supports the COMET trial’s extended follow-up—ensuring this study can continue.

“The importance of BRCF’s support in collecting ongoing data on these patients cannot be overstated.  This analysis is the first important step, but long-term follow-up data will be critical in order to change treatment options for these women in the future,” Dr. Hwang said. “BCRF has been an extraordinary partner in their support for evidence-based de-escalation of DCIS treatment. They have also supported the patient advocate collaborators on our team, who have helped to keep patients and their well-being at the center of our study.”

BCRF’s Chief Scientific Officer Dr. Dorraya El-Ashry said that these findings are provocative and could potentially change how low-risk DCIS is treated—but only if investigators like Drs. Hwang and Partridge can do the necessary validation to make sure active monitoring is safe.

“With BCRF support, they can,” she said. “This study is just one of many where BCRF’s unique ability to identify and support high-risk, high-reward science can be impactful. Together with our community of donors and supporters, we’ll accelerate progress.”