Cardiac Damage from Treatments
One of the hard-to-wrap-your-brain-around things about cancer treatment is the possibility that the drugs to save your life can result in other serious medical problems. This is right up there with the need to change a life-long dictate of avoiding radiation exposure and being told to lie down under the machine if radiation therapy is part of your plan. Since we understand the serious risks of untreated or inadequately treated cancer, most of us swallow hard and proceed with our doctors' advice. Women who are receiving adriamycin and/or herceptin may worry especially about the possibility of cardiac damage from these drugs. They are never given together and, usually, periodic monitoring of cardiac function is part of a woman's care. I have known a few women who needed to stop herceptin because of a negative change in cardiac function. They were all women with Stage IV breast cancer who were receiving weekly infusions for an indefinite period of time (as opposed to women who receive herceptin for a total of a year as part of adjuvant treatment). In all but one case, these women were able to resume the treatment after a break of several months.
Anyway, a recent article by Proctor and colleagues in the Journal of Clinical Oncology is reassuring about all of this, suggesting that the damage is less often and less severe than most of us imagine. Here is a nice summary from Komen that includes a link to the full article if you are interested:
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Low Incidence of Heart Complications with Herceptin in Breast Cancer
Even with longer-term follow-up, heart problems are not common among breast cancer patients treated with Herceptin® (trastuzumab). These results were published in the Journal of Clinical Oncology.
Twenty to 25 percent of breast cancers overexpress (make too much of) a protein known as HER2. Overexpression of this protein leads to increased growth of cancer cells and a worse breast cancer prognosis. Fortunately, the development of drugs such as Herceptin that specifically target HER2-positive cells has improved prognosis for women with HER2-positive breast cancer.
Herceptin may be used in addition to chemotherapy. Anthracycline-based chemotherapy regimens are effective against breast cancer but can increase the risk of heart problems when combined with Herceptin.
Understanding the frequency of these heart problems is an important part of weighing the risks and benefits of treatment with Herceptin.
Researchers from the HERceptin Adjuvant (HERA) trial evaluated the incidence of heart complications among women with HER2-positive breast cancer who were treated with Herceptin following completion of chemotherapy. Participants had normal left ventricular ejection fraction (LVEF, a measure of heart function) before beginning Herceptin. They were assigned to one year of treatment with Herceptin or observation. The
majority of women (94%) had been treated with anthracyclines. 5% of women stopped taking Herceptin due to heart complications.
At a follow-up of more than three years, overall incidence of heart complications was low, with only a slight increase in the Herceptin group (0.8% experienced congestive heart failure; 3.6% had a decrease in LVEF). Many of the heart problems experienced by patients in the Herceptin group were reversible.
The researchers concluded that the incidence of heart complications associated with treatment with Herceptin is low, even after longer-term follow-up. An accompanying editorial notes that treatment of HER2- positive breast cancer "has been a major clinical advance"; as such, further understanding of the safety of
Herceptin is an important step in continuing to improve treatment for this patient population.
References: Procter M, Suter TM, Azambuja E, et al. Longer-term assessment of trastuzumab-related cardiac adverse events in the HERceptin Adjuvant (HERA) trial. Journal of Clinical Oncology [early online
publication]. June 7, 2010.