Ductal carcinoma in situ, or DCIS, comprises about 20% of new breast cancer diagnoses. DCIS is often called stage 0 cancer and is considered non- or pre-invasive. In this form of the disease, cells within the milk duct have become cancerous but haven’t spread outside the duct. It's typically treated with surgery and possibly radiation, but a new study finds that active monitoring may be just as safe. 

Research recently published in the Journal of the American Medical Association, and presented at the San Antonio Breast Cancer Symposium, compared the results of active monitoring of DCIS versus traditional treatment, i.e., surgery with or without radiation.

To conduct the study, just under 1,000 newly diagnosed DCIS patients were split into two groups, each trying one of these methods. The active monitoring group went in for follow-up appointments every six months. Most also had hormone therapy. The findings showed that each group’s chances of developing invasive breast cancer were comparable, suggesting that monitoring may be an option for many patients.

Dr. E. Shelley Hwang, co-principal investigator from the Duke Cancer Institute, says, “Many women wonder, ‘Do I really need to do this to myself?’ when they’re faced with surgery and possibly radiation to remove DCIS. These early results from our study give us reassurance that active monitoring is safe in the short term and that the cancers that are diagnosed during active monitoring are detected at an early stage.”

Among the women in the study who were actively monitored, 4.2% had developed invasive cancer after two years, compared with 5.9% of the standard treatment group. Dr. Hwang says they believe the lower rate in the first group may be linked with more than 70% of patients pairing active monitoring with hormone blockers. This suggests hormone therapy may be key in the success of active monitoring.

A separate analysis by the same team found that quality of life, symptoms, and mental health impacts were also comparable in both groups, indicating that one or the other doesn’t cause more physical or mental stress on patients.

Though the findings are promising, the researchers caution that further studies are needed to determine if active monitoring is appropriate for DCIS patients.

Dr. Hwang says, “These early results are provocative and potentially exciting for patients, but we clearly need more long-term follow-up. If these results hold up over time, most patients who have this type of low-risk disease will have the option of avoiding invasive treatments. That would be a complete change in how we care for these patients and think about this disease.”