Survivorship care after breast cancer has traditionally focused on one question: is the cancer coming back? As patients live longer after treatment, that focus has widened, and clinicians are paying attention to an organ that quietly absorbs much of therapy’s strain—the heart. Over time, cardiovascular (CV) disease has emerged as a leading cause of death among breast cancer survivors, influenced in part by the treatments that saved their lives.

That reality is the focus of the DECODE Heartland (DECODE) study, led by Melinda Stolley, PhD, Associate Director of Population Sciences and Co-Leader of the Cancer Control Program, and Andreas Beyer, PhD, Co-Director of the Basic and Translational Research Program in Cardio-Oncology. DECODE examines how cancer therapies affect CV health and why some patients experience greater risk than others. It is designed to detect early biological changes linked to future heart and vascular disease, and identify opportunities to reduce that risk during and after treatment.

“Cancer therapies are incredibly effective, but they can also leave lasting effects beyond treating the disease itself. We want to understand how those effects shape cardiovascular health so we can better protect patients well beyond treatment,” said Dr. Stolley.

DECODE follows breast cancer patients over time, directly measures how different therapies affect blood vessel function, and tests whether a home-based exercise program during treatment can reduce CV risk. Its design is strengthened by deep, translational expertise in vascular biology and cardio-oncology, connecting changes in blood vessels to real-world patient outcomes.

“This work lets us see risk earlier and with more precision. By understanding how cancer therapies affect the circulatory system, we can begin to anticipate problems instead of reacting to them years later,” said Andreas Beyer, PhD, Co-Director of the Basic and Translational Research Program in Cardio-Oncology.

Inside the Vascular Response to Cancer Therapy

A central focus of DECODE is understanding how cancer treatment affects blood vessels and why those changes matter. For many years, cardio-oncology research concentrated primarily on damage to the heart muscle. Increasing evidence now shows that injury to the circulatory system, particularly small blood vessels, can play an early and important role in CV disease.

Dr. Beyer’s research expertise strengthens this component of the study. Trained in genetics and physiology, his work examines how blood vessels respond to stress and injury at both molecular and functional levels. His laboratory uses advanced imaging and live human blood vessel tissue to observe vascular changes as they occur, including changes that may not yet cause symptoms.

“We see signs of vascular stress and inflammation occurring very early during cancer treatment,” said Dr. Beyer. “Those changes do not always cause immediate problems, but they can quietly set the stage for cardiovascular disease.”

Earlier studies from Beyer’s lab showed that certain cancer therapies can trigger inflammatory responses in small blood vessels and disrupt normal vascular function. These findings helped clarify how cancer treatment contributes to vascular injury and informed the study’s design.

DECODE builds on this work by pairing laboratory-based testing with patient data. In the lab, researchers use pressure myography—a technique that allows scientists to observe how small blood vessels respond to stress and pressure—to compare how different cancer therapies affect vascular function using tissue from diverse healthy donors. In the clinical setting, patients undergo assessments of CV fitness and vascular health before and after treatment, allowing researchers to link biological changes to patient outcomes.

The study also evaluates whether a virtual, home-based exercise program during treatment can help protect vascular health. While exercise is known to benefit the CV system, maintaining physical activity during chemotherapy is often difficult.

“Our focus is on strategies patients can realistically use during treatment,” said Dr. Beyer. “Exercise is one option, and understanding the biology behind its benefits may also help us identify new approaches when exercise is not feasible.”

Survivorship as a Clinical Priority

DECODE reflects the MCW Cancer Center’s commitment to making survivorship care a clinical priority, not an afterthought. As more patients live longer after cancer, understanding and reducing treatment-related CV disease has become essential to improving both quality of life and long-term health. Findings from DECODE could help guide safer treatment choices, support earlier screening, and strengthen how clinicians monitor CV risk.
“This work is about helping patients live well long after cancer treatment ends,” said Dr. Stolley. “Protecting cardiovascular health has to be part of how we define successful cancer care,” said Dr. Stolley

The study is grounded in team science and collaboration beyond MCW, with partners at Strategic Focused Research Network sites at Augusta University, Boston University, and the University of Pennsylvania. Support from the American Heart Association, MCW Cancer Center, MCW Cardiovascular Center, Advancing a Healthier Wisconsin Endowment, and the WE-Care Foundation made this work possible, alongside essential contributions from trainees, coordinators, and support staff.

Learn more about DECODE Heartland.