A study suggests that a new way to measure heart damage caused by certain breast cancer treatments may find damage earlier than traditional tests.
The new measurement is longitudinal strain and it's measured by a heart ultrasound.
Using a heart ultrasound to measure longitudinal strain is considered experimental and most doctors who read echocardiograms have little experience with the technique.
In this study, the researchers also looked at high-sensitivity troponin 1 levels in blood samples to check for heart damage. While troponin testing isn't done routinely, some cancer centers monitor the troponin levels of people receiving certain chemotherapy medicines to determine if the medicines are causing heart problems.
Herceptin (chemical name: trastuzumab) is a targeted therapy used to treat advanced-stage, HER2-positive breast cancer and to lower the risk of recurrence of early-stage, HER2-positive breast cancer with a high risk of recurrence. HER2-positive cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that tell the cancer to grow and spread. About one out of every four breast cancers is HER2-positive. Herceptin works by attaching to the HER2 protein and blocking it from receiving growth signals.
Herceptin may cause serious side effects, including heart damage that can lead to heart failure. Still, most patients don't have serious heart problems while getting Herceptin. And even if heart problems do develop, medicines can help improve heart function and the heart can repair itself over time.
The chemotherapy medicines:
- Adriamycin (chemical name: doxorubicin)
- Ellence (chemical name: epirubicin)
- Doxil (chemical name: doxorubicin)
- daunorubicin (brand names: Cerubidine, DaunoXome)
- mitoxantrone (brand name: Novantrone)
are anthracyclines. These medicines often are used to treat advanced-stage breast cancer, as well as to reduce the risk of early-stage breast cancer coming back (recurring).
Like all chemotherapy medicines, anthracyclines can cause serious side effects. Anthracyclines may cause heart damage that can lead to heart failure. Still, limiting the amount of an anthracycline chemotherapy medicine used can help avoid serious heart problems.
Anthracycline chemotherapy medicines sometimes are used together with Herceptin to treat HER2-positive breast cancer.
Doctors typically check heart function at the beginning, during, and after treatment with either an anthracycline chemotherapy medicine or Herceptin. The heart function test result is called an ejection fraction. The ejection fraction is a measure of how effectively the heart is pumping. Unfortunately, if the ejection fraction is reduced, the heart may already be damaged from treatment.
In this study, 43 women diagnosed with HER2-positive breast cancer were treated with an anthracycline chemotherapy medicine plus Herceptin or an anthracycline chemotherapy and then Herceptin.
All the women had standard ejection fraction testing during treatment. The researchers also measured the women's longitudinal strain and high-sensitivity troponin 1 levels at the start of anthracycline treatment, then 3 months after anthracycline treatment started, and again 6 months later when the anthracycline treatment ended and Herceptin treatment was going to start.
Women who had a 10% increase in longitudinal strain 3 months after treatment started were 500 times more likely to have serious heart problems later.
About 66% of the women who were later diagnosed with serious heart problems had elevated troponin levels 3 months after treatment.
The results suggest that measuring longitudinal strain and troponin levels can help figure out if heart problems are starting to develop much earlier than traditional ejection fraction testing. Knowing earlier that heart problems are developing could help doctors adjust the treatment plan to avoid further damage.
If you've been diagnosed with breast cancer and an anthracycline chemotherapy medicine and/or Herceptin are part of your treatment plan, talk to your doctor about how your heart health will be monitored during treatment. You also may want to ask how your treatment plan will be changed if you do develop heart problems. While longitudinal strain testing is considered experimental, many doctors do check troponin levels to detect heart problems early. You may want to ask if checking troponin levels makes sense for you.
Reading about serious treatment side effects such as heart problems can be understandably scary. Still, you need to make sure you're getting the care that is best for YOU. You can learn more about coping with fears about side effects and treatment on the Breastcancer.org Dealing With Chemotherapy Fears page.
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