About eight years ago, the cancer drug Herceptin attracted glowing attention for the role it plays in preventing the recurrence of certain types of breast cancer.

For a minority of patients, however, there was a dark side to this “miracle drug: ” increased the risk of heart failure and stroke.

Cancer treatment can be hard on the heart. It might aggravate pre-existing heart disease – high blood pressure, for example, can get worse with chemotherapy – as well as causing problems where none existed before.

“When you are treating people for cancer, you don’t want to give them other long-term problems,” says Dr. Susan Dent, a medical oncologist at The Ottawa Hospital Cancer Centre who founded the Canadian Cardiac Oncology Network in 2011.

“Worldwide, this is becoming an extremely hot topic.”

Doctors in Ottawa created the first cardiac oncology clinic in Canada in 2008, mostly to treat women with breast cancer who needed to carefully balance cancer and cardiac care.

Five years later, the clinic has treated about 500 patients with a broad range of cancers, cardiac oncology clinics are springing up all over North America, and cardiologists from across Canada visit the Ottawa clinic to observe how it works.

Thursday and Friday, Ottawa is hosting the nation’s first cardiac oncology conference to focus on the complex relationship between cancer treatment and heart disease.

The conference has attracted 90 medical experts from all over Canada and as far away as Tennessee, Arkansas and Texas. Among the subjects to be discussed: radiation-induced heart disease, the long-term heart complications of childhood cancer, and how to detect cardiac toxicity in breast cancer.

“Heart disease and cancer are the two biggest killers of people in the world,” says Dent. “It makes sense to bring the two groups of people together so we can talk.”

There are a number of different kinds of cancer-cardiac interactions. “Cardio toxicity” is damage that occurs while taking chemotherapy.

Cardiologist Peter Liu, the scientific director of the University of Ottawa Heart Institute, will present a keynote speech at the conference on biomarkers, one of the most promising ways to diagnose heart injury in real time.

Other heart damage can crop up years after cancer treatment. There might be cumulative damage caused by taking a succession of cancer drugs. Cancer survivors, like many people, face cardiac disease as they age, and this might be complicated by the life-saving drugs they took earlier in life.

It’s hard to say how many cancer patients will be affected long-term, or long it takes for the damage to emerge as cancer patients survive longer.

In many cancer centres, patients are treated and discharged back to their family physicians, says Dent. It’s possible that they are developing cardiac problems years later that isn’t linked to cancer treatment.

When the Ottawa clinic first opened, there was virtually no published research on the relationship between cancer treatment and heart disease.

That has changed, says Dent. There’s better knowledge about cancer drugs and how they affect the heart, and how to balance cancer and cardiac treatment.

Ottawa Citizen
Thursday, June 20, 2013
Page: C2
Section: City
Byline: Joanne Laucius
Column: Joanne Laucius
Source: Ottawa Citizen

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