Cancer treatments can increase the risk of heart problems but there are ways to reduce this serious problem, University of Newcastle Professor Aaron Sverdlov says.
Professor Sverdlov, a cardiologist and researcher, said anti-cancer drugs were "very effective".
"They're a necessary evil," he said, adding that they can come with side effects.
Professor Sverdlov will join a panel of experts and patients for a free online event on Wednesday night.
The event, run by the Newcastle-based Breast Cancer Trials and moderated by ABC broadcaster Annabel Crabb, will discuss breast cancer and heart health.
A key topic will be that drugs such as chemotherapy, radiation and immunotherapy can cause side effects such as high blood pressure, abnormal heart rhythms and heart failure.
This problem, known as "cardio-toxicity", refers to damage or dysfunction of the heart muscle caused by medications or treatments.
However, the general health of patients who take these drugs plays a key role in how susceptible they are to developing side effects.
"It's important for people to manage diet and weight, exercise and not smoke," Professor Sverdlov said.
Hunter research, released last year, found that cancer survivors had "an eight-fold increased risk of developing cardiovascular disease" due to drug side effects.
"The risk differs depending on what treatment a person gets for cancer, and the type of person," Professor Sverdlov said.
Young people who get low-grade cancer in their early 20s, exercise and live a healthy lifestyle have a low risk of side effects.
"Someone in their late 70s with diabetes, high blood pressure and high cholesterol has a high risk," he said.
Professor Sverdlov said obesity, smoking, poor diet and lack of exercise were risk factors for cancer and heart disease.
"So it's not surprising that people with cancer are more likely to have cardiovascular disease - a lot of the risk factors are the same," he said.
"If we can manage those things early on, ideally before cancer occurs, we reduce the risk of heart problems later on, and in some cases may even improve cancer treatment success."
The healthier the person, with good diet and exercise habits, the less likely they are to suffer side effects.
"But if you have more risk factors, the chances of cardio-toxicity is proportionally higher," he said.
It was important to know which people were at higher risk of side effects, so "we can monitor them more closely and potentially start them on some cardio-protective therapies".
But it was equally important to pinpoint those with low risk of side effects, so they could avoid potentially expensive tests that were unnecessary.
A Breast Cancer Trials statement said "recognising the signs of cardio-toxicity is crucial for early intervention and management".
Symptoms may include: shortness of breath, chest pain or discomfort, fatigue, swelling and irregular heartbeat.
"Oestrogen, a hormone that plays a key role in breast cancer development, may also affect the cardiovascular system," the statement said.
"Women who undergo hormonal therapy for breast cancer may experience changes in their cholesterol levels and blood pressure, which can contribute to cardiovascular complications."
The free online event runs from 5pm to 6.30pm on Wednesday.
