Anthracycline chemotherapy medicines:
- Adriamycin (chemical name: doxorubicin)
- Doxil (chemical name: doxorubicin)
- Ellence (chemical name: epirubicin)
have helped increase breast cancer survival rates. Still, anthracyclines can have toxic effects on the heart.
Herceptin (chemical name: trastuzumab) is a targeted therapy medicine used to treat HER2-positive breast cancer. Heart muscle damage and heart failure are also possible serious side effects of Herceptin, especially when Herceptin is given with or after anthracycline chemotherapy.
Women who will be treated with anthracycline chemotherapy and/or Herceptin should have their heart function tested before treatment starts and should be continually monitored for any developing heart problems during treatment.
A study has found that doctors’ decisions about whether a woman diagnosed with early-stage breast cancer has baseline heart function testing before chemotherapy starts is based on the type of chemotherapy she will be receiving and not on her personal risk of heart problems. This suggests that a number of women at higher risk for treatment-related heart problems are not getting baseline heart testing.
How many women in each treatment group had baseline testing?
The research was published online on May 23, 2018, by the Journal of Clinical Oncology. Read the abstract of “Risk-Imaging Mismatch in Cardiac Imaging Practices for Women Receiving Systemic Therapy for Early-Stage Breast Cancer: A Population-Based Cohort Study.”
The researchers looked at the treatment records of 18,444 women from Ontario, Canada, who were diagnosed with early-stage breast cancer between 2007 and 2012 and treated with chemotherapy and/or Herceptin. The women were 47 to 63 years old:
- 20.3% of the women were diagnosed with stage I disease
- 43.7% of the women were diagnosed with stage II disease
- 20.7% of the women were diagnosed with stage III disease
- for 15.3% of the women, cancer stage information wasn’t available
The researchers divided the women into four groups based on the treatment they received:
- anthracycline chemotherapy only (no Herceptin): 10,160 women
- Herceptin with no anthracycline chemotherapy (included chemotherapy with medicines other than anthracyclines): 832 women
- anthracycline chemotherapy followed by Herceptin: 3,154 women
- other chemotherapy (no anthracyclines and no Herceptin): 4,298 women
The researchers also looked to see how many of the women had heart function testing before chemotherapy and/or Herceptin treatment started. Heart testing included:
- cardiac MRI
- multigated acquisition (MUGA) scan, a test that measures the pumping function of the ventricles, the lower chambers of the heart
The researchers then looked to see how many women had risk factors for heart failure, including:
- coronary artery disease, the hardening and narrowing of the arteries caused by a build up of plaque in the arteries
- atrial fibrillation, irregular and often rapid heart beat that increases the risk of stroke and heart disease
- high blood pressure
- chronic kidney disease
- high cholesterol and/or triglycerides, which can cause plaque to build up in the arteries
- chronic obstructive pulmonary disease, chronic inflammation of the lungs that makes it hard to breathe
Women with cardiac risk factors were less likely to have baseline testing
The researchers then analyzed how many women with and without risk factors for heart failure had baseline heart testing by treatment group.
In the anthracycline chemotherapy only treatment group, 6,840 women (67.3%) had baseline heart testing:
- 73.3% of the women with at least one risk factor for heart failure had testing
- 62.6% of the women with no risk factors had testing
In the Herceptin with no anthracycline chemotherapy treatment group, 779 women (93.6%) had baseline heart testing:
- 93.6% of women with at least one risk factor for heart failure had testing
- 93.6% of women with no risk factors had testing
In the anthracycline chemotherapy followed by Herceptin treatment group, 3,017 women (95.7%) had baseline heart testing:
- 95.0% of women with at least one risk factor for heart failure had testing
- 96.2% of women with no risk factors had testing
In the other chemotherapy treatment group, 972 women (22.6%) had baseline heart testing:
- 21.8% of women with at least one risk factor for heart failure had testing
- 24.4% of women with no risk factors had testing
Overall, the results showed that women who had at least one risk factor for heart failure had baseline imaging less often than women with no risk factors.
In all treatment groups, compared to women with no risk factors for heart failure, women who had at least one risk factor had a higher risk of a major cardiac event, which the researchers defined as:
- being hospitalized or visiting the emergency room for heart failure
- pulmonary edema (when the lungs fill with fluid)
- cardiomyopathy (enlarged, thickened, or stiffened heart)
- an outpatient diagnosis of heart failure
- dying from a cardiovascular problem
The number of major cardiac events was highest in women with at least one risk factor for heart failure who were treated with an anthracycline followed by Herceptin.
The researchers pointed out that women with at least one risk factor for heart failure treated with anthracycline chemotherapy only had a higher risk of a major cardiac event, but lower rates of baseline heart testing, compared to women with no risk factors treated with Herceptin only.
Also, while the risk of a major cardiac event was similar for women treated with anthracycline chemotherapy only and women treated with an anthracycline followed by Herceptin, women treated with anthracycline chemotherapy only had lower rates of baseline heart testing.
Type of chemotherapy is best predictor of baseline testing
The researchers then looked to see if any factors were linked to a higher chance of having baseline heart testing. Overall, the type of treatment was the best predictor of whether a woman would have baseline heart testing.
“There is general agreement that cardiac [testing] is appropriate before cancer treatment, particularly in those who receive anthracyclines and/or trastuzumab, especially in the context of additional [cardiac] risk factors,” the researchers wrote. “This is supported by the National Comprehensive Cancer Network Clinical Practice Guidelines and other consensus documents. A limitation of these guidelines, however, is that they recommend baseline [testing] primarily on the basis of the treatment regimen as opposed to the patient’s overall risk of heart failure.
“This risk-imaging mismatch is an impetus to reconsider current cardiac [testing] practices in patients who receive chemotherapy for breast cancer,” the researchers added.
If you’ve been diagnosed with breast cancer and anthracycline chemotherapy and/or Herceptin will be part of your treatment plan, it’s a good idea to ask your doctor about your risk of treatment-related heart problems and how your heart function will be monitored during treatment.
You also may want to ask if visiting a cardiologist before treatment starts is a good idea for you, especially if you have any risk factors for heart disease, such as high blood pressure or coronary artery disease. The cardiologist can evaluate your heart function and decide if you’re at high risk for developing heart disease or heart failure from breast cancer treatment.
Together, you can decide on the best treatment and monitoring plan for your unique situation.
To discuss the risks and benefits of chemotherapy treatment with others, join the Breastcancer.org Discussion Board forum Chemotherapy - Before, During, and After.