In the metastatic setting, a number of patients on trastuzumab and anti-HER2 therapies have cardiotoxicity issues and cannot continue the drug. In this video, , a medical oncologist at Duke University, discusses how such patients can be treated in an adjuvant setting.
The following is a transcript of her remarks:
Since the anti-HER2 agents came out, we've noticed that cardiotoxicity is an issue. In the metastatic setting, we learned that cardiotoxicity can be dose limiting or actually treatment limiting for anti-HER2 therapies, especially with Herceptin (trastuzumab). Over the course of research and different trials that have been done, in the metastatic setting we see there are a certain number of patients who get heart failure and cannot continue the drug. So research has started to be done on how to reverse that and how to keep people on therapy, because trastuzumab and anti-HER2 therapies are really lifesaving in people with HER2-positive metastatic breast cancer.
Since we learned that anti-HER2 therapies were so very successful in the metastatic setting, they have been brought into the adjuvant setting. Since they cause decrease in heart function and some people get heart failure, we monitor very, very carefully for decreases in heart function, looking at ejection fraction usually with echocardiograms, MUGA scans traditionally, or other ways. Certainly, we monitor for symptoms. In metastatic disease, we check baseline heart function and we carefully look for risk factors that we know increase the risk of decline in cardiac function like prior or concurrent use of anthracyclines, age over 50 or older, and being on an antihypertensive treatment. There are other risk factors such as having a BMI over 25 and maybe having diabetes, especially in very older patients, but the major things are having had anthracyclines and being older.
Then we monitor for symptoms carefully. A common question that I get is how often do I monitor patients? In the metastatic setting, since the drug is lifesaving and really a key part of their treatment, we continue treatment and we monitor for symptoms. We don't necessarily monitor on a regular basis for looking at ejection fraction. In patients who are in the adjuvant setting, on the other hand, since most of the treatment that we use in the adjuvant studying is preventive and we don't know that they have cancer present, we're treating to prevent recurrence in the long run.
There's a risk-benefit weighing that goes on. If the risk is very, very high, we might stop treatment or continue treatment longer if there is a decline in ejection fraction, but if the risk is very, very low, we stop. In the adjuvant setting, we check baseline heart function, and then you check heart function if the patient is getting an anthracycline after they get the anthracycline. Then we also check heart function every 3 months during treatment to make sure there is not a decline in heart function that would prompt maybe holding or sending the patient to a cardio-oncologist so they can consider preventive treatments for more heart function decline and continue the successful treatment.