Popular Breast Cancer Drug Could Cause Heart Problems

5:01 PM, Jan 23, 2012   |    comments
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COLUMBUS, Ohio (James Cancer Hosptial) -- Doctors have known for decades that the drug doxorubicin can be very effective in treating breast cancer. What they don't know is how much damage, if any, it might do to a woman's heart in the process.

First developed in the 1950's, and partially named for its ruby red color, doxorubicin has long been suspected of posing a rare but significant risk for heart damage. But when, exactly, might that damage occur?

"That's the $64,000 question," said Dr. Charles Shapiro, director of breast medical oncology at Ohio State University's Comprehensive Cancer Center. "Who is at
risk? And, if heart damage does occur, will it manifest and increase as a woman ages? We just don't know all the facts."

To try and find out, Shapiro and a team of researchers will follow more than two dozen women through the course of their treatment over the next several months. Before chemotherapy starts, and every time it is given, researchers here will use sensitive blood tests and high-definition images to look for even the slightest signs of damage to a woman's heart.

"The first part of the problem is defining what proportion of women this actually affects," said Dr. Maryam Lustberg of Ohio State's James Cancer Hospital. "So, we are looking to
find the early markers of heart toxicity so that in the future we can intervene earlier."

Normally, when patients are given doxorubicin, doctors monitor their hearts with traditional echocardiograms, which can be performed quickly and easily in an exam room. But those tests may not tell doctors all they need to know.

"By the time changes are visible on the echocardiogram, indicating a decrease heart function, it's already too late," said Shapiro. "The damage is done."

Instead, researchers here will take a sample of blood from patients and test it for a certain type of cell, known as an endothelial precursor cell. These cells are known to be
produced by the body in greater numbers when the heart is damaged.

Then, they will perform a cardiac MRI on these volunteers, to get a real-time, highdefinition image of their hearts. "Cardiac MRIs give you very good tissue resolution," said Lustberg. "You can see swelling occurring at very early stages in the heart," she said.  "You can also see valve changes that you might not otherwise see as well. So, it gives you a lot more information than an echocardiogram might."

Searching for those small clues could make a big difference to patients like Linda Nazareth. Diagnosed with breast cancer in May 2011, Linda was prescribed doxorubicin and immediately signed up for the clinical trial involving it. And with good reason.

"My grandmother on my dad's side had breast cancer a long time ago," said Nazareth.  "My dad told me that she would start getting sick as soon as they started the medicine and it did damage her heart."

Knowing that a relative was treated with the same drug and experienced some heart problems made Linda a perfect fit. Even if the study doesn't help her immediately, she wanted to participate. "Anything that I can do to help someone else get through their journey, I wanted to do," she said.

If doctors do notice any changes in Linda's heart, the good news is, they can react immediately.  "In those cases, other types of chemotherapy could be substituted," said Lustberg. "There
are other potential cardio-protective medications that could potentially be used as well."

For now, the first step is to better define just who is at risk and when heart damage may occur. "I don't want to mislead anybody," said Shapiro. "Doxorubicin is one of the best drugs in breast cancer. But we've got to contend with this small, increased risk of heart damage."

"Most women with breast cancer today will be long-term survivors," added Shapiro, "and we need to make sure that we're not damaging other organs in the process of treating breast cancer, that may not manifest until 10 or 20 years down the road."

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