Heart Problems From Trastuzumab Not a Long-Term Issue
Researchers with the BIG 1-01 trial have found that serious heart problems are seen more often in women who take trastuzumab than those who don’t. However, those problems are still rare overall and it’s most likely they’ll happen during the treatment, not years afterward.
About 15 to 20 percent of breast cancers are HER2-positive. This means the tumor has extra amounts of a protein called human epidermal growth factor receptor 2 (HER2). Trastuzumab (Herceptin) is a targeted therapy, meaning it focuses on certain cells or proteins, in this case, HER2 proteins, and tries to stop those cells with high levels of the HER2 protein from growing.
Researchers with the Herceptin Adjuvant Trial (HERA) evaluated the use of trastuzumab in women with early-stage breast cancer removed by surgery. They found that when taken after chemotherapy, trastuzumab greatly lowered the risk of cancer coming back for women with early-stage, HER2-positive breast cancer. Other studies have found trastuzumab combined with chemotherapy may work even better.
Serious heart problems have been reported with trastuzumab. For this reason, researchers with the BIG 1-01 trial used the HERA data to look at the heart health of participants 8 years after they were treated with trastuzumab.
The more than 5,000 women who participated in HERA were divided into three groups:
- One group received 1 year of trastuzumab
- One group received 2 years of trastuzumab
- One group received no trastuzumab
All of the women had completed breast surgery and had received chemotherapy. Their heart health was measured using a physical exam, a questionnaire and various scans. They were monitored when the trial began, and then again at 3, 6, 12, 18, 24, 30, 36 and 48 months later. After that, their heart health was measured annually between years 5 and 10.
The number of women who stopped taking their medicine because of heart problems was:
- 9.4 percent of those in the 2-year group
- 5.2 percent of those in the 1-year group
Severe congestive heart failure happens when the heart can’t pump enough blood to give the body enough oxygen and nutrients. Eight years after taking trastuzumab, severe congestive heart failure was seen in:
- Less than 1 percent of those in the 1-year group
- Less than 1 percent of those in the 2-year group
- No one in the group that didn't receive trastuzumab
Left ventricular ejection fraction (LVEF) is a way to measure how well your heart is pumping blood. Low LVEF can indicate serious heart problems. Eight years after taking trastuzumab, a significant decrease in LVEF was seen in:
- 7.2 percent of those in the 1-year group
- 4.1 percent of those in the 2-year group
- Less than 1 percent of those in the group that didn't receive trastuzumab
When it happened, this decrease was reversible in 87.5 percent of the women in the 2-year group and 81.2 percent of the women in the 1-year trastuzumab group.
Women who had previous serious heart problems, either before or during chemotherapy, were not eligible for HERA. This may be part of the reason for the low number of serious heart problems seen after treatment with trastuzumab.
The length of time between anthracycline chemotherapy, a treatment associated with heart problems, and use of trastuzumab was longer in this trial than in others. This may or may not have impacted the findings.
What This Means for You
The researchers on this study concluded that though serious heart problems were seen more in those who took trastuzumab than those who didn't they were rare overall and were more likely to happen during the treatment than years afterward. Women who did experience serious heart problems were likely to see those problems reversed.
If you are or were being treated with trastuzumab for early-stage, HER2-positive breast cancer, these findings may make you feel better about the effects the treatment may have on your long-term heart health.
Your lifestyle can have a big impact on your health. Talk to your doctor about what you can do to keep your heart healthy during cancer treatment and beyond.
De Azambuja, E, Procter, MJ, van Veldhuisen, DJ, et al. Trastuzumab-Associated Cardiac Events at 8 Years of Median Follow-Up in the Herceptin Adjuvant Trial (BIG 1-01). Journal of Clinical Oncology. 2014; doi: 10.1200/JCO.2013.53.9288.