Protecting the heart alongside fighting prostate cancer

Studies worldwide show that about one in five prostate cancer patients has pre-existing cardiovascular disease, which is also one of the most common causes of death among patients with localised prostate cancer.

November is Prostate Cancer Awareness Month. According to doctors interviewed, the aim of treatment goes beyond effecting managing the cancer; it must also ensure that the patient’s cardiovascular health and quality of life are not unnecessarily compromised. Before starting cancer treatment, patients should have a comprehensive cardiovascular risk assessment rather than focus solely on the tumour.

Professor Tan Huay Cheem, chairman of the Singapore Heart Foundation (SHF), told Lianhe Zaobao (LHZB) that cardiovascular disease is a major cause of death among prostate cancer patients partly because the two conditions share several risk factors. “Both are associated with ageing, chronic inflammation, endothelial damage and oxidative stress. Obesity, sedentary lifestyles, smoking, and diets high in red meat, processed meat and saturated fat all increase the risk of both diseases.”

Prostate cancer treatment itself may also increase cardiovascular risk, particularly androgen deprivation therapy (ADT). “ADT can cause metabolic changes such as increased abdominal fat, abnormal blood lipid levels, insulin resistance and arterial calcification. Long-term use may increase the risk of major cardiovascular events such as heart attacks and strokes. Before starting cancer treatment, patients should not focus solely on the tumour, but should also undergo a comprehensive cardiovascular risk assessment. This includes checking for a history of heart disease, heart attack, stroke or heart failure; whether blood pressure is well controlled; whether cholesterol and other blood lipid levels are normal; and whether they have diabetes or abnormal blood sugar levels. Weight, degree of obesity, lifestyle, smoking, family history of cardiovascular disease and other relevant risk factors should also be assessed.”

Associate Professor John Yuen, head and senior Consultant of Urology at Singapore General Hospital, said in an interview that cardiovascular disease is relatively common among men diagnosed with prostate cancer. “The presence of pre-existing heart disease is therefore an important consideration when deciding on the most appropriate treatment. Our priority is not only to achieve good cancer control, but also to ensure that treatment is safe and does not unnecessarily compromise the patient's cardiovascular health or quality of life.”

Yuen said patients considering surgery, particularly robotic-assisted laparoscopic radical prostatectomy, would have their cardiovascular function and ability to tolerate general anaesthesia assessed. Patients with unstable heart disease, a recent heart attack or recent coronary stent placement may need to have their heart condition optimised before surgery. “In some cases, surgery may need to be deferred, particularly when patients require potent antiplatelet medications or anticoagulants that cannot be safely interrupted. Robotic surgery offers advantages such as smaller incisions, reduced blood loss and faster postoperative recovery compared with conventional open surgery. However, careful cardiovascular assessment remains essential, as robotic prostatectomy involves pneumoperitoneum and a steep Trendelenburg position, which can affect cardiovascular and respiratory function.”

Radiotherapy is an effective alternative for patients unsuitable for surgery, but it may cause inflammation and damage to the lining of the bladder and rectum, leading to blood in the urine or rectal bleeding. These effects may sometimes appear months or even years after treatment ends. Yuen said: “These bleeding complications can be particularly troublesome in patients who require long-term antiplatelet or anticoagulant therapy for their heart disease. In some patients, bleeding may be recurrent and difficult to manage. This is an important factor that should be discussed when comparing surgery and radiotherapy, although it does not necessarily preclude radiotherapy.”

For patients with low-risk prostate cancer, active surveillance may be an appropriate option, allowing them to avoid or defer treatment-related risks. Patients with more advanced disease may need hormone therapy and other systemic treatments, but these may also affect cardiovascular health. “Treatment decisions should be individualised, taking into account the aggressiveness of the prostate cancer, severity of cardiovascular disease, life expectancy and patient preferences. Close collaboration between urologists, cardiologists, radiation oncologists and anaesthetists is essential to achieve the best balance between cancer control and cardiovascular safety.”

Associate Professor Yuen added: “Androgen deprivation therapy is an important treatment for patients with advanced prostate cancer, and is also frequently used in combination with radiotherapy for selected patients with localised or locally advanced disease. While ADT is highly effective in controlling prostate cancer, reducing testosterone levels can lead to significant metabolic and cardiovascular changes, particularly with prolonged treatment.” Among the most common effects of ADT are increased body fat and reduced muscle mass. Patients may also develop insulin resistance, higher blood sugar, adverse changes in cholesterol levels and reduced physical fitness. Together, these changes may increase the risk of diabetes, cardiovascular disease and other metabolic complications. Patients with pre-existing cardiovascular disease, diabetes, high blood pressure or obesity are particularly vulnerable.

For patients with existing cardiovascular risk factors, Professor Tan Huay Cheem is most concerned about whether these worsen after cancer treatment and whether new cardiovascular disease develops. “During treatment, particular attention should be paid to changes in blood pressure, blood sugar, blood lipids, weight and cardiovascular symptoms. Different prostate cancer drugs also carry different cardiovascular risks. Combining ADT with androgen receptor signalling inhibitors (ARSIs) roughly doubles the risk of serious cardiovascular events, with a more pronounced increase among patients with non-metastatic hormone-sensitive prostate cancer.”

On when prompt intervention is needed, Tan said patients should seek timely reassessment by a doctor if they develop new or markedly worsening chest pain or tightness; breathlessness or a marked decline in exercise tolerance; palpitations or fainting; swelling in the legs or breathing difficulties at night; or significantly uncontrolled blood pressure, blood sugar or blood lipids. These issues should not be left until cancer treatment ends. “We should not wait until patients develop heart disease before intervening. Instead, we should identify and control risks early, so that, as far as possible, patients can complete their cancer treatment safely and without interruption.”

Yuen said the focus should not be solely on cancer control. Blood pressure, weight, waist circumference, blood sugar or glycated haemoglobin (HbA1c), and blood lipids should be checked regularly, alongside assessments of cardiovascular symptoms and physical fitness. Several measures can help minimise these risks. Patients should adopt a healthy lifestyle, with regular aerobic exercise and resistance training to maintain muscle mass and cardiovascular function, and prevent excessive weight gain. A balanced diet, quitting smoking and moderating alcohol intake are equally important.

Yuen said the choice of hormone therapy also warrants careful consideration for patients with serious cardiovascular disease. Recent evidence suggests that gonadotropin-releasing hormone (GnRH) antagonists may be more favourable for cardiovascular health than GnRH agonists in some patients, although the evidence is not entirely consistent.

Unnecessarily prolonged ADT should also be avoided, provided this does not compromise cancer treatment outcomes. “The success of prostate cancer treatment should not be measured by cancer control alone. As survival outcomes improve, many patients live for years or even decades after diagnosis. Our responsibility is to ensure that they not only survive cancer treatment, but also maintain good cardiovascular health, physical function and quality of life throughout their cancer journey.”

Tan offered the following advice on reducing cardiovascular risk during treatment:

· Manage weight and avoid abdominal obesity: ADT itself may increase visceral fat, making it particularly important to maintain a healthy weight.

· Exercise regularly: Regular exercise can help protect against prostate cancer and safeguard cardiovascular health.

· Aim for a healthy diet: Eat more vegetables, fruit, whole grains, legumes and fish, and cut back on processed meat, red meat and foods high in saturated fat. A healthy diet and regular exercise offer protection against both diseases.

· Keep blood pressure, blood sugar and cholesterol under control: This is particularly important for patients who already have high blood pressure, diabetes or high cholesterol. These “traditional cardiovascular risk factors” must not be neglected during cancer treatment.