Some chemo drugs can cause heart disease; two docs work on solution

Iris Bouvet
Iris Bouvet finished chemotherapy for breast cancer about a year ago. Her doctor also put her on a medication he hopes will prevent her from developing heart disease which can be caused by some chemo drugs.
MPR Photo/Lorna Benson

Imagine surviving breast cancer, only to learn a few years later that your chemotherapy treatment had seriously damaged your heart.

Up to 10 percent of cancer patients who receive a common class of drugs go on to develop congestive heart failure. Doctors don't want to stop using the medications. But they also don't want their patients to trade one life-threatening condition for another.

A cardiologist and a cancer doctor in Edina believe they have found a solution to the dilemma.

Dr. Steven Heifetz sees a lot of cancer patients in his practice, but he's not a cancer doctor. He's a cardiologist at Fairview Southdale Hospital.

Delivering grim news is a necessary part of his job, but Heifetz says it seems particularly unfair when his patient has just conquered cancer.

"There's nothing worse than thinking, 'I had cancer. I'm a cancer survivor. Everything's fine.' And then finding out later that you have heart disease, and it may or may not be curable," he said.

Heifetz wanted to know if there was a way to prevent the heart damage caused by a class of chemotherapy drugs called anthrocyclines. He found a handful of studies that had reported success using a beta blocker called Carvedilol.

"There's nothing worse than thinking, 'I'm a cancer survivor.' And then finding out later that you have heart disease."

Beta blockers slow down the heart and they lower blood pressure. Carvedilol, in particular, has antioxident properties. Heifetz says heart damage caused by chemotherapy drugs is often due to oxidation.

The literature results were preliminary, meaning it wasn't wise to read too much into them. Still, Heifetz was intrigued. He decided that there was little risk in trying Carvedilol on patients during their chemotherapy treatments, because the drug's side effects are minimal and it's an affordable, generic medication.

"The amazing thing about it is it's about $20 for a six-month supply of the pill. You can't get much cheaper than that. And you're preventing a devastating disease," said Heifetz.

Dr. Steven Heifetz
Dr. Steven Heifetz is a cardiologist at Fairview Southdale Hospital.
MPR Photo/Lorna Benson

He partnered with Dr. Barbara Bowers, an oncologist at Fairview Southdale Breast Center in Edina. Together, Bowers and Heifetz, both University of Minnesota physicians, created an onco-cardiology clinic, where Bowers treats the patients' cancer and Heifetz's team tracks their heart function.

In the three years they've been working together, they say none of their more than 50 patients have shown any signs of cardiac damage. Dr. Bowers says typically by this point, a small percentage of her patients would have already developed heart failure.

"It's been pleasing up to this point that we may be pointing in the right direction," she said.

Bowers says she will feel more confident in the results when her patients reach the five or 10-year mark without any signs of heart damage.

It's been about a year since Iris Bouvet finished chemotherapy for breast cancer. During the dark and painful weeks when she was being treated, the Lakeville resident sought solace by playing the piano.

Bouvet says she cried when Dr. Bowers explained all the things that chemotherapy could do to her body.

Bouvet remembers hearing about the risk of heart disease. But she fixated on the possibility of nerve damage in her fingers, which could prevent her from playing the piano.

"I think that actually freaked me out more than the heart thing," she said.

In retrospect, Bouvet says she's glad her doctors were thinking about the risks to her heart, and put her on Carvedilol.

"My mother and her mother both had congestive heart failure. My father had a triple bypass when he was older. There's just a lot of heart issues in the family," Bouvet said.

It's still much too early to tell if the Carvedilol therapy actually protects the heart from damage caused by anthracycline chemotherapy drugs. But there's a growing interest in the theory. Harvard University recently announced that it will open a new cardio-oncology program to address the heart-related side effects of cancer therapies.

Fairview Southdale's Dr. Steven Heifetz says presumably, a program of that scale will be able to generate more meaningful data on the effectiveness of drugs like Carvedilol.

"We don't want to make a national policy until we're really sure that it's correct. So I'm actually thankful that places like Harvard are going to have larger studies," he said.

Heifetz and Bowers do not recommend that other doctors use Carvedilol to prevent heart damage in their cancer patients at this point. They say it will take at least a few more years to determine if the effects they're seeing are real.

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