Growing numbers of hospitals are creating cardio-oncology programs to monitor patients for cardiotoxicity from chemotherapy and radiation therapy. Cancer patients may beat the actual cancer, but later find the therapy caused irreversible damage to their heart, leading to heart failure. Collaboration between oncology and cardiology has been key in monitoring these patients and initiating early cardiac care when necessary.
To find out key points hospitals need to consider when creating these programs, Cardiovascular Business sought advice from Marielle Scherrer-Crosbie, MD, PhD, director of the cardiac ultrasound laboratory and and a professor of medicine with the Hospital of the University of Pennsylvania.
"Cardio-oncology is a recent subspecialty, but it is becoming more and more important. With the aging of the population, we have more and more patients who have both cardiovascular diseases and cancer, and it does take a specific training to treat many of those patients because they have such complex pathologies that interact with one another, and complex treatments that also unfortunately interact with the heart," Scherrer-Crosbie explained.
Collaboration and communication are key
Scherrer-Crosbie emphasized the collaborative nature of cardio-oncology. A cardio-oncologist needs to work closely with oncologists to ensure seamless coordination between cardiovascular and oncological treatments.
"This is not a subspecialty that you can do in a vacuum. And so the cardio-oncologist needs to be very collaborative with the oncologist. The oncologist needs to be on board. The very important thing is that the cardio-oncologist needs not to appear like a threat to the patient, like someone who is going to stop the oncology treatment," she said.
Scherrer-Crosbie highlighted the involvement of oncologists from various subspecialties, heart failure specialists, electrophysiology specialists, pharmacologists and imaging specialists. The collaborative effort among these professionals is crucial for addressing the complex pathologies and interactions between cardiovascular and cancer treatments.
While the cardiac imager plays a key role in monitoring any changes in cardiac function that may signal a negative impact on the heart, a pharmacologist can be very helpful on the care team because of their deep understanding of all the drug interactions and the difficulty in adjusting doses, she said.
Role of imaging in cardio-oncology
Cardiac imaging, particularly echocardiography, plays a pivotal role in evaluating cardiotoxic effects. Scherrer-Crosbie said echo is the first line of defense in assessing the impact of cardiotoxic drugs by looking at left ventricular (LV) dysfunction, but it also plays a role in detecting cardiac tumors and assessing thrombotic events associated with treatment, new onset arrhythmias and heart failure. While echo remains fundamental, cardiovascular magnetic resonance (CMR) and computed tomography (CT) also contribute to the comprehensive evaluation of cardio-oncology patients, so a multi-modality cardiac imager might be ideal.
Cardiac ultrasound strain is used in a high percentage of patient assessments because it is more more sensitive to detect patients at risk of complications. Strain often can show changes in the heart before the impact is seen in LV ejection fraction (LVEF).
Strain is recommended in all cardio-oncology patients by American College of Cardiology (ACC), European Society of Cardiology (ESC) and the International Cardio-Oncology Society (IC-OS) because of its prognostic value in identifying patients who may not do well, explained Scherrer-Crosbie.
Scherrer-Crosbie said strain is usually not performed if the LVEF is above 60 or 65 because the strain will probably be normal anyway. But, when the LVEF is borderline at the lower limits of normal, between maybe 50 and 55, she said the strain is usually abnormal
"It sort of makes you aware that maybe this patient is slightly at higher risk. So that is certainly how in our lab we use strain. We look at the strain value of 16%. If it's less than 16%, then we tend to be a bit more on the alert for this particular patient," Scherrer-Crosbie explained.
While some industry guidelines have recommended strain in high-risk patients only, she added, there is limited data on the cost-effective nature of that modality.
The role of CT and MRI in cardio-oncology
While CMR is crucial to the diagnosis of myocarditis, CT also has a role to play in assessing these patients, who are often very susceptible to atherosclerosis.
"Some patients have common risk factors or mutations that predispose them both to cancers and atherosclerosis, but also the treatments themselves are often conducive to fast atherosclerotic development," Scherrer-Crosbie explained. "Even the new immune checkpoint inhibitors have been shown to be responsible for more progressively serious atherosclerosis."
Should cancer therapy be stopped if it impacts cardiac function?
The answer to this question is typically "no," because it is important to eradicate the cancer and disruptions in therapy can allow tumors to regain ground. However, if the patient has symptoms during treatment, they should immediately undergo echocardiography to check strain and LV function. If it appears there is a notable amount of damage to the heart, the care team can then discuss their options.
Frequency of cardiac imaging exams during cancer treatment
Addressing the frequency of imaging exams during these treatments, Scherrer-Crosbie noted the importance of a baseline echo for all cancer patients undergoing cardiotoxic therapy. This was a recommendation in a recent ACC Cardio-Oncology Council (Scherrer-Crosbie is a member) and ACC Imaging Section state-of-the-art review.
There have been some recommendations to conduct follow-up echo exams after around 250 milligrams per square meter dose of anthracyclines to make sure that the LV function is okay. She said there are also some recommendations that say cardiac ultrasounds should be performed every one or two cycles.
Cancer treatment drugs and their impact on the heart
Anthracycline agents have been used since the 1970s as a primary chemotherapy agent to treat cancer, but these drugs are known to cause damage to the heart, especially in higher doses. Scherrer-Crosbie said there has been a movement to try to use less anthracyclines through recommendations by the ACC and ESC councils on cardio-oncology, and the IC-OS. These groups also recommend at least one echo after the anthracycline treatment to make sure that the patient's cardiac function is preserved from baseline.
"Certainly anthracycline patients are at higher risk of LV dysfunction and heart failure than patients with other treatments. But I don't think you should completely forget about other treatments. There are some tyrosine kinase inhibitors that also have pretty strong effects on LV function too," she stressed.
Focus on anthracycline agents and strain imaging
Scherrer-Crosbie highlighted anthracycline agents as a significant concern due to their known cardiotoxicity. Recommendations include a post-anthracycline echo to ensure cardiac function preservation. Strain imaging, with its high prognostic value, is recommended for cardio-oncology patients, especially when LVEF is borderline.
Scherrer-Crosbie is an expert in strain imaging and she had hopes that its greater sensitivity to detect dysfunction earlier than ejection fraction (EF) would help improve outcomes. However, a recent highly anticipated trial failed to show the improvement, and she said more research is needed.
"The recent study SUCCOUR trial was eagerly awaited by the cardio-oncology community ... [it] looked at implementing a strain-guided versus EF-guided therapy in patients receiving anthracyclines," she explained. "This study had negative results."