Vaccines have helped prevent many serious illnesses. Now, researchers are studying whether a vaccine could also help stop certain breast cancers before they develop.

A first-of-its-kind clinical trial from UPMC and the University of Pittsburgh is examining whether a vaccine can produce an immune response in women diagnosed with ductal carcinoma in situ, or DCIS. The study began in Pittsburgh in 2024 and expanded to central Pennsylvania in 2026.

Often called Stage 0 breast cancer, DCIS occurs when abnormal cells are found inside a milk duct but have not spread into the surrounding breast tissue. Although DCIS is not invasive, it can progress to invasive breast cancer in some patients.

Surgery to remove the abnormal cells is generally the first line of treatment. The vaccine being studied is not intended to replace surgery. Instead, researchers are evaluating whether it can strengthen the body’s immune response and help prevent DCIS from developing into invasive cancer or returning later.

The investigational vaccine is given in three doses. Participants are randomly assigned to different study groups. Those assigned to the vaccine group receive three doses before undergoing the standard recommended surgery.

After surgery, researchers can examine the removed tissue and evaluate how the immune system responded. Participants will then be monitored for years to determine whether the abnormal cells return.

This is an early and carefully controlled step in the research process. The trial will help researchers better understand the vaccine’s safety and effectiveness. If the findings are promising, the study may expand to include more women at additional cancer centers.

The trial is open only to a specific group of patients. Potential participants must be women age 50 or older who are postmenopausal and have been diagnosed with early-stage DCIS. The clinical research team must review each patient’s medical history and circumstances to determine eligibility.

The vaccine is not currently available to the general public, nor is it intended for individuals who have not been diagnosed with DCIS. It is important to view this research as a promising possibility rather than an established way to prevent breast cancer.

Clinical trials play an essential role in advancing cancer care. Many treatments used today were first evaluated through carefully designed studies. Trials allow researchers to study new treatments, diagnostic tools and preventive approaches while closely monitoring patient safety. Participation is voluntary, and patients receive information about a study’s purpose, possible benefits, potential risks and other treatment options before deciding whether to enroll.

While vaccine research represents an exciting area of study, it does not change the importance of established breast health practices. Women should talk with their health care provider about their personal risk factors, family history and recommended screening schedule.

Early detection remains one of our most effective tools against breast cancer. Regular screening can identify changes before symptoms appear, when treatment may be most effective.

The long-term goal of this research is ambitious: stopping breast cancer before it develops. Researchers do not yet know whether this vaccine will achieve that goal, but the trial represents an important step toward new possibilities in cancer prevention.

Susan Branton, M.D., medical director, UPMC Magee-Womens, Breast Health Center, sees patients at 1100 Grampian Blvd., Williamsport. To make an appointment, call 570-326-8200, and for more information, visit UPMC.com/BreastNCPA.