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Collaboration between cardiologists, oncologists may improve CV outcomes during, after cancer treatment
SAN ANTONIO — There continues to be an unmet need regarding CVD prevention in patients who are currently receiving cancer treatment or are cancer survivors, although partnership with cardiology and oncology may help improve outcomes, according to a presentation at the American Society for Preventive Cardiology Congress on CVD Prevention.
Prevalence of CVD, cancer mortality
The two leading causes of death worldwide are CVD and cancer, Ana Barac, MD, PhD, director of the cardio-oncology program at MedStar Heart and Vascular Institute in Washington, D.C. and associate professor of medicine and oncology at Georgetown University, said during the presentation. Lately, there has been exponential growth in novel cancer treatments that have the potential to affect the CV system. There is also rapid growth in the number of patients who survived cancer and received different kinds of treatment, and have a high burden of CV risk factors.
“Almost no single cancer patients, unless they were treated with surgery, received only one drug,” Barac said. “Remember that, because in our guidelines, we always focus on one drug, and they almost never were treated with one.”
There is new knowledge on the synergism between cancer, CV risk and the risk from cancer treatment, although knowledge gaps persist regarding CV evaluation and treatment.
“This is where this group can make a major impact in trying to understand where that link is and how we can make cardiovascular care part of cancer treatment,” Barac said.
Several CV conditions have been associated with cancer treatment such as hypertension, HF and atrial fibrillation. In addition to cardiologists, oncologists must also be made aware of this increased risk.
“People who are really the key to engage with these patients are the oncologists because patients go to see them,” Barac said. “Their primary problem is typically cancer unless you are really seeing a true survivor or somebody who’s completed treatment.”
Originally, guidelines on this topic were lacking, but now there are numerous guidelines that suggest several methods of preventing and treating patients with cancer and CVD. An expert consensus statement was published in the Journal of the American Society of Echocardiography in 2014 on multimodality imaging evaluation of patients during and after cancer therapy. In 2017, the American Society of Clinical Oncology (ASCO) published guidelines on the prevention and monitoring of cardiac dysfunction in patients who survived adult cancers.
Different breast cancer treatments can contribute to different CV conditions in a patient. For example, HF or cardiomyopathy may typically be seen in patients who take anthracyclines or HER2-targeted therapy. All systemic chemotherapy is associated with decreased oxygen uptake, and CDK4/6 inhibitors may lead to prolonged QT. Radiation increases the risk for CAD and HF with preserved ejection fraction, and aromatase inhibitors increase the risk for hyperlipidemia and, likely through it, CVD, according to the presentation.
The writing group for the ASCO guidelines included specialties such as cardiology, family medicine, radiation oncology, exercise physiology and oncology. Barac said preventive cardiology was not represented in the writing group, but hopefully that will be integrated in the future.
These guidelines also detail several clinical questions to determine how to treat these patients, including which patients with cancer are at increased risk for cardiac dysfunction, which preventive strategies minimize this risk before and during therapy initiation, and surveillance and monitoring approaches during and after cancer treatment.
Reconciling different guidelines is one of the current challenges in the preventing and treatment of CVD in patients who were treated for cancer and can be achieved only through the development of new evidence. More data are needed on treatment strategies for patients who were treated for cancer and have CVD.
There has been a focus on cardiac imaging with cancer treatment, although the issue is that most patients never receive cardiac imaging.
“We keep on talking only about 25% of breast cancer patients that get routine and frequent imaging,” Barac said. “The vast majority never get imaged. For us, what that means is that cardiovascular risk factors most often do not get assessed. Usually the echocardiogram is the only trigger to send a patient to a cardiologist, so there’s a big group of patients that we do not even know about.”
Several questions persist regarding the benefits of screening patients, including whether it will improve outcomes, can it lead to potential harms, leading to oncology treatment compromise, cost, feasibility and whether it is justified in many patients.
Although CVD and breast cancer have different risk factors, they also share many, including age, diet, family history, obesity/overweight, physical inactivity and tobacco use, according to the presentation.
Further research
More research is needed in the connection between breast cancer and CVD, but recent studies coming from the analysis of the Women’s Health Initiative have provided insight into the potential link between CVD and breast cancer. In one analysis of women, Women’s Health Initiative patients who developed breast cancer and were followed during a 11.3-year period, the main causes of death were breast cancer (28%), CVD (21%) and other causes (23%). In this study, the presence of three to four cardiometabolic risk factors strongly correlated with the CVD deaths, while only obesity correlated with increased risk for breast cancer death.
Another recent study from this cohort published in JAMA Oncology in 2018 found that patients from the Women’s Health Initiative who consumed a low-fat diet had an improved 10-year survival rate compared with those who consumed a standard diet. There were also fewer deaths related to breast cancer, other cancers and CVD.
A longer, 20-year follow-up analysis of the Women’s Health Initiative was presented at the ASCO annual meeting in June 2019 by Rowan Chlebowski, MD, PhD. This report identified that during 20-year follow-up, women assigned a low-fat diet had lower rates of breast cancer mortality compared with those assigned a standard diet.
“This is one opportunity of very high interest for both oncologists and cardiologists because it’s affecting overall death, it’s affecting cardiovascular death and it’s affecting death from breast cancer,” Barac said. – by Darlene Dobkowski
Reference:
Barac A. Cardio-Oncology: Evolving opportunities for CVD prevention. Presented at: American Society for Preventive Cardiology Congress on CVD Prevention; July 19-21, 2019; San Antonio.
Disclosure: Barac reports she is the cardiology principal investigator for the SAFE-HEaRt study and received honoraria/fees from Bristol-Myers Squibb.