The number of novel cancer treatments has exploded, resulting in substantial improvements in prognosis and life expectancy. However, many cancer treatments are associated with adverse effects, including cardiotoxicity. Mortality related to cardiovascular disease (CVD) in patients with cancer is approximately double that of the general population,1 and the impact of cancer treatments on cardiovascular (CV) health is substantial. Given that patients are living longer with cancer due to improvements in treatment, cardiotoxicity and cardiac health have emerged as important survivorship issues.

Family physicians are well placed within care teams to know their patients’ CV risks prior to cancer treatment. They are often the care providers patients see when side effects related to cancer treatment arise, and they continue to provide care to patients after completion of cancer treatments in both curative and noncurative settings. Therefore, a family physician’s understanding of the potential CV impact of cancer treatments is essential. This article aims to highlight family physicians’ roles in helping to identify and reduce CV risk in cancer patients, recognize and treat cardiotoxic effects of cancer treatment, and raise awareness of some of the more commonly used cancer treatments associated with cardiotoxicity. This list of treatments and cardiotoxic effects presented here is not exhaustive, and it is important to understand that there are subtle differences in cardiotoxicity even within the same class of drugs.

Risk reduction

The risk of developing cancer treatment–related CV toxicity depends on a patient’s baseline risk level and changes over time as they are exposed to 1 or more cardiotoxic therapies.2 Identifying and treating potentially reversible CV risk factors can help improve patients’ quality of life,3 and tolerance of cancer treatments and is already within family physicians’ scope of care. Family physicians are well situated to help optimally manage CV risk factors such as smoking, obesity, alcohol consumption, sedentary lifestyle, diabetes, and hypertension.4 Communication of known CV risk factors and CV history to the patient’s cancer care team is essential as the risks, including CV toxicity risk, and benefits of proposed cancer treatments are carefully weighed and discussed with the patient before initiating any new therapy and may affect ongoing monitoring recommendations. Cardio-oncology specialist involvement may also be indicated, depending on the patient’s clinical situation and CV risk.

Cardiotoxic effects of cancer treatments

A wide variety of cardiac and CV toxicities are associated with cancer treatment. For example, patients undergoing surgery for cancer are at risk of perioperative CV complications such as myocardial ischemia and infarction, arrhythmia, and heart failure. Concurrent treatment, such as prior radiation therapy and specific systemic therapies, can increase this risk.5 This necessitates CV risk assessment before patients undergo surgery.

Radiation therapy to the chest carries an increased risk of developing CV complications despite newer radiation techniques used to reduce both the incidental radiation dose received by the heart and the total volume of the heart receiving radiation. Acutely, the most common cardiac complication is pericarditis,6 while late complications can include coronary artery disease, cardiomyopathy, valvular heart disease, chronic pericardial disease, and conduction abnormalities.

Several systemic therapy agents are associated with potential CV toxicities. Table 1 summarizes the potential CV toxicities of some standard systemic therapies.7-26 The table is intended to provide a snapshot and is not exhaustive.

Table 1.

Potential CV toxicities of select systemic cancer therapies

New cancer treatments are continually being incorporated into clinical practice. Some of the newest therapies include chimeric antigen receptor T-cell therapy and bispecific T-cell engager therapy. Cardiotoxicities noted with the use of these agents include heart failure, myocardial dysfunction, valvular dysfunction, arrhythmias, and coronary artery disease.27 It is also important to note that many patients will have received other cardiotoxic cancer therapies before these newer therapies are used.

As patients present to their family physicians with new symptoms suggestive of cardiotoxicity, prompt recognition, management, and communication with the cancer care team are essential.

Cardiovascular monitoring recommendations

Patients can take select therapies such as endocrine therapy, targeted therapy, and immune checkpoint inhibitor therapy for many months to years. Cardio-oncology specialists are often consulted and follow patients in high-risk situations. Cardiovascular toxicity monitoring protocols are available for various cancer therapies.19 Depending on the clinical situation and goals of care, family physicians can play a role in monitoring treatment tolerance, particularly when shared follow-up care is in place or when patients are discharged back to primary care while receiving cancer therapy. Monitoring recommendations particularly relevant to primary care providers include monitoring patients who are receiving endocrine therapies (see Boxes 1 and 2).1,10,11,19,28-30 Some cardiotoxic side effects also do not manifest for many years following treatment, such as cardiomyopathy from anthracycline use or radiation-induced coronary artery disease. Family physicians are often the first point of contact for survivors of cancer years posttreatment. This includes a growing population of adult survivors of pediatric cancers.

Box 1. Monitoring recommendations for patients with breast cancer receiving endocrine therapies

Physicians should perform a baseline CV assessment—including taking a history, performing a physical examination, and screening for reversible risk factors (eg, measuring blood pressure, fasting blood glucose levels, lipid levels, and HbA1c levels) as well as performing an ECG and discussing healthy lifestyle choices.

A baseline 10-year CVD risk assessment for patients without pre-existing CVD is also recommended.19,28,29

Annual CV risk assessment is recommended for those with a high 10-year risk of CV events.

Consider a CV risk assessment every 5 years in patients with low or moderate 10-year risks of CV events.19

CV—cardiovascular, CVD—cardiovascular disease, ECG—electrocardiogram, HbA1c—hemoglobin A1C.

Box 2. Monitoring recommendations for patients with prostate cancer receiving ADT

Physicians should perform a baseline CV risk assessment — including taking a history, performing a physical examination, and screening for reversible risk factors (eg, measuring blood pressure, fasting blood glucose levels, lipid levels, and HbA1c levels) as well as performing an ECG and discussing healthy lifestyle choices.

A baseline 10-year CVD risk assessment for patients without pre-existing CVD is also recommended.1,10,11,19,30

While a patient is receiving ADT, an annual CV risk assessment is recommended.

Periodic ECGs are recommended for those at high risk of corrected QT interval prolongation.19,30

ADT—androgen deprivation therapy, CV—cardiovascular, CVD—cardiovascular disease, ECG—electrocardiogram, HbA1c—hemoglobin A1C.

Family physicians should be aware that CV toxicity monitoring protocols have been published for a wide variety of cancer therapies19 beyond the scope of this article. Our understanding of potential toxicities, including CV risks and monitoring recommendations, continues to evolve.

Conclusion

Family physicians play an essential role in identifying and helping manage patients’ modifiable CV risks, communicating risks to other members of the patient’s cancer care team, and maintaining a high index of suspicion when patients with a history of or currently receiving cancer therapy present with signs or symptoms suggestive of cardiotoxicity. Family physicians also play a role in monitoring patients for CV toxicity in select clinical situations.

Notes

Oncology Briefs is a quarterly series that provides evidence-based reviews of key oncology topics relevant to family practice and postgraduate education. The series covers topics ranging from screening, diagnosis, and treatment to survivorship care and more. The series is coordinated by Dr Anna N. Wilkinson of the Cancer Care MIG (Member Interest Group) at the College of Family Physicians of Canada; articles are reviewed by members of the Cancer Care MIG.

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