What Is the Relationship Between Cancer and Heart Disease?

Cancer increases the risk of death from various heart conditions, particularly heart attack. Cancer treatments, as well as the disease itself, can raise this risk. The risk of heart attack is high from diagnosis through the end of treatment and even afterward. It is therefore vital that cancer patients and people previously treated for cancer do not ignore symptoms such as chest pain that could indicate a heart attack, and act immediately to seek medical help.

Cancer patients and survivors may have a higher heart attack risk than the general population. This can worry patients and their families, but awareness of the risk and how to manage it can improve quality of life. Paying attention to heart health is important from cancer diagnosis, throughout treatment and afterward.

Although cancer patients and people who have received treatment face an increased heart attack risk, they need awareness and steps to protect heart health rather than fear. Regular checkups, attention to symptoms and prompt medical help when needed are vital. Cancer patients and survivors should therefore take their heart health seriously and keep up with their checkups without becoming fearful.

What Is the Heart Attack Risk for Cancer Patients?

Most studies suggest a link between cancer and heart attack. Cardiovascular disease is a major risk factor for heart attack, and cancer also has a strong association with cardiovascular risk.

“Heart attack” is also referred to medically as “myocardial infarction” or an “ischemic coronary event.” This serious condition falls within the category of cardiovascular diseases. The main types of cardiovascular disease are shown below.

Studies on Cancer and Cardiovascular Disease Risk

A 2017 study found that cancer patients had a higher heart attack risk over a 6-month period than patients without cancer (4.7% and 2.2%, respectively). The rate was particularly high in patients with lung cancer (8.3%). The risk also increased with advanced cancer stages.

Another study conducted in the United States in 2019 found that more than 10% of cancer patients die from cardiovascular disease. The study examined patients with 28 different cancer types between 1973 - 2012. Of 3.2 million cancer patients, 38% died from cancer and 11.3% from cardiovascular disease.

The risk of cardiovascular death in cancer patients can be outlined as follows:

• Patients with lung cancer have the highest risk.
• This risk is also substantial in 8 different cancer types.
• The risk of death is substantial in people diagnosed with cancer before age 35.
• This risk is particularly high within the first year after a cancer diagnosis.

Another study in 2020 produced similar findings, showing a generally higher risk in younger patients diagnosed with cancer. It also found that the risk of heart disease, including heart attack, increased over time in cancer survivors.

A similar study in 2022 examined adult cancer survivors and found a 42% increase in cardiovascular disease risk and a 52% increase in heart failure risk.

Cancer Treatment and Heart Disease

Unfortunately, treatment for some cancers can trigger heart problems or reveal pre-existing underlying heart disease.

Cancer treatments, particularly chemotherapy, can directly harm the heart. Some drugs can also change platelet behavior and increase the risk of blood clot formation.

Invasive procedures, including some operations, can also create a risk of blood clots, causing heart attack or other problems such as pulmonary embolism. Surgery always poses a clotting risk, particularly when patients need to remain in bed for a long time afterward.

Such risks exist in every area of medicine, and every treatment recommendation involves weighing them against possible benefits. When deciding on treatment, doctors and patients should discuss and assess the benefits and potential complications of specific options together. All medical procedures are carefully planned and performed according to the circumstances, minimizing potential risks to achieve the best outcomes and overall health goals.

Effects of Chemotherapy on the Heart

Although chemotherapy is used to treat cancer, it can also damage the heart. It can increase the risk of several heart conditions, including heart disease, heart attack and heart failure. Unfortunately, chemotherapy does not target only cancer cells. It also destroys many healthy cells, including heart cells.

Heart Matters published an article stating that the chemotherapy drug doxorubicin (adriamycin) carries a risk of heart failure in 7 out of 100 people who take it.

Effects of Targeted Drugs on the Heart

Targeted therapies such as Herceptin, containing trastuzumab, a targeted drug commonly used in breast cancer, can cause cardiac side effects in particular. Trastuzumab can lead to heart failure and impaired left ventricular contractile function. Cardiovascular risk factors, older age and previous anthracycline chemotherapy (adriamycin and epirubicin) increase susceptibility to trastuzumab-induced cardiac side effects, with anthracycline exposure being the most important risk factor. Starting beta blockers and angiotensin-converting enzyme inhibitors may prevent trastuzumab-induced cardiac side effects. Rates of cardiac side effects with other HER2-targeted treatments appear to be substantially lower than with trastuzumab.

Cardiology follow-up generally depends on the treatment course and the patient’s individual risk factors. Typically, during active treatment, echocardiography (ECHO) every 3 months is recommended; follow-up after treatment may range from 1 to 5 years.

Effects of Immunotherapy on the Heart

Immune checkpoint inhibitors are immunotherapies that have brought important advances in treating various cancers. They include agents such as monoclonal antibodies targeting CTLA-4, PD-1 and PD-L1. However, these treatments can very rarely cause immune-related cardiovascular side effects. Immunotherapy can lead to various immune-related adverse events, including auto-myocarditis, pericarditis and vasculitis (inflammation of the heart muscle, its lining and blood vessels).

Although rare, these side effects should be considered whenever cardiac symptoms or complaints occur. For example, the frequency of immunotherapy-related myocarditis ranges from 0.1% to 1%.

Risk factors for these immune checkpoint inhibitor side effects include pre-existing cardiovascular disease, previous and concurrent cardiotoxic treatments, underlying “automatic diseases” (the wording in the Turkish source), tumor-related factors, concurrent immune-related toxic effects and genetic factors. Considering these factors is important for managing the side effects appropriately.

Symptoms of Cancer-Related Heart Disease

Remember that heart disease can occur without symptoms. Symptoms of cancer-related heart conditions do not differ from those of other forms. In general, some signs to watch for include:

• High blood pressure
• High cholesterol or diabetes
• Chest pain
• Shortness of breath
• Nausea
• Heartburn
• A feeling of chest discomfort or tightness

Because cancer patients and survivors have an increased risk of heart disease, they should see a cardio-oncologist or cardiologist regularly for assessment. The symptoms above and any other concerns should be discussed with a specialist. People experiencing the following should also consult a specialist:

• Newly developing heart conditions
• Side effects arising from cancer treatment
• A new condition that increases heart disease risk, such as diabetes

For chest pain, shortness of breath or other emergencies, call 112 immediately or seek emergency care. Do not drive in these situations.

Treatment and Prevention of Cancer-Related Heart Disease

Cancer treatment is adjusted according to the patient’s risk of heart disease, heart attack or blood clots. Treatment options for cancer patients with a history of heart failure or heart attack may be changed, for example by choosing a different chemotherapy drug.

Although heart attack treatment varies by person, its basic goal is the same: to help the heart pump blood and eliminate an existing clot or prevent a possible clot from forming.

Emergency heart attack interventions include blood-thinning medicines such as aspirin and clopidogrel, painkillers, oxygen, coronary angiography with balloon or stent placement, and bypass surgery to replace completely blocked coronary arteries.

Can every cancer patient do something to reduce heart attack risk? Although the risk cannot be eliminated completely, it can certainly be reduced as much as possible. Heart-healthy lifestyle choices can help lower the risk:

• Quitting smoking
• Being physically active
• Eating a balanced, healthy diet
• Considering other cancer treatment options

The Link Between Cancer and Heart Attack: A Summary

Cancer patients face an increased risk of cardiovascular disease. This is due not only to cancer and its treatments but also to the shared causes of these two disease groups. As a result, more than 10% of cancer patients die from cardiovascular disease.

Cancer patients should be aware of heart attack risk and seek medical help in emergencies.

Research shows that cancer patients have a higher heart attack risk than people without cancer. Different cancer treatments can adversely affect the heart. Heart health needs attention during cancer treatment.

Cancer patients and survivors should see a cardiologist regularly. They should know the symptoms of heart disease and seek medical help immediately in emergencies. Cancer-related heart disease treatment is planned according to risk factors. Lifestyle changes can help reduce heart attack risk.