Trial Results: A promising new approach may help women with DCIS determine their personal risk of developing invasive breast cancer

Ductal carcinoma in situ (DCIS) is a common, pre-invasive form of breast cancer. With DCIS, cells that line the milk ducts of the breast have become cancerous, but they have not spread into surrounding breast tissue. Most cases are diagnosed by a mammogram before causing any symptoms. 

The typical treatment for DCIS is surgery. Many people then go on to have radiation, a treatment with the sole purpose of preventing recurrence. However, most DCIS cases will never develop into invasive cancer. Thus, there is concern about patients receiving radiation treatments that will not benefit them, given that the risk of recurrence is already low. On the other hand, some patients will develop invasive breast cancer. Estimates of DCIS cases that will become invasive breast cancer range from 20-50 percent.

Currently, there is no way of telling whether DCIS will develop into invasive breast cancer, which is why most cases are treated the same way. At the 2023 San Antonio Breast Cancer Symposium, Seema A. Khan, MD, a researcher with the ECOG-ACRIN Cancer Research Group, presented the results of study E4112, the first prospective trial of its kind. After following participants for 5 years, it found that a gene test (on tissue collected during surgery) identifies women with high-risk DCIS who will likely benefit from radiation while informing those with low-risk disease about the possibility of safely skipping it. 

With this information, women and their doctors can confidently decide whether to have radiation—or not. 

Below are two interviews with Dr. Khan (Bluhm Family Professor of Cancer Research at the Feinberg School of Medicine and Lurie Comprehensive Cancer Center at Northwestern University in Chicago).  

Can Patients With DCIS Safely Avoid Radiation Therapy?

In this video produced and published by Patient Power, Dr. Khan explains what she and her colleagues found and how this new approach differs from the current standard of care. She describes treatment planning and when patients should talk to their doctor if they are interested in avoiding radiation. 

Genomic Test Helps Decide Which Patients with DCIS Need Radiation

In this Breastcancer.org Podcast, Dr. Khan and senior editor Jamie DePolo discuss the DCIS Score and the design of study E4112, including why a prospective study is important. They talk about the trial results and how they fit into the current context of DCIS care.