One of the most effective chemotherapy drugs for my type of breast cancer is adriamycin. This drug is a class of drugs called anthracyclines. But this drug is also pretty toxic. It has been nicknamed “the red devil” by cancer patients. In addition to nausea, vomiting, and low blood counts, it can cause heart damage. Although the risk of heart damage that results in heart failure is low (2-5%), this is a devastating side effect and the overall prognosis for the patient’s survival is poor.(1)
Given that I have no risk factors for cardiovascular disease, the potential benefit of using adriamycin as part of my treatment to increase the chance for cure, was definitely worth the potential risk. To understand my baseline heart function, I had an echocardiogram which is an ultrasound of the heart, and thankfully, my heart function was normal.
I did wonder however, what impact intense exercise would have on my risk of heart damage due to adriamycin. Should I tone things down a bit with the idea of putting less stress on my heart at a time when there were other things putting stress on my heart such as adriamycin specifically, but also just overall effects of chemotherapy on my body such as anemia.
I was encouraged when I found this paper that reported on the results of a clinical study where patients with early stage breast cancer who were receiving adriamycin were either part of a group given a specific exercise prescription and compared to those in the usual care, non-exercising group.(2) They studied 28 patients who chose to either be in the exercise group or the usual care group. The exercise group was prescribed an exercise program that was carefully designed around their chemotherapy treatments with the overall intensity of the exercise increasing over time. All patients underwent testing before, during and after treatment which included exercise testing to determine VO2 max, echocardiography, blood tests and exercise cardiac magnetic resonance imaging.
One of the most important findings was that the exercise group did not have a significant drop in their functional capacity at the end of chemotherapy treatment based on exercise testing. The VO2 max for the exercise group dropped 4% compared to 15% for the control group. This 15% drop is described as the equivalent of aging 15 years! Reminder that this AC chemotherapy is typically given over 2-3 months. Fifteen years of aging over 3 months! No thank you!
They also found that the exercise group had a lower rise in troponin, a blood test that can indicate heart damage (21.4 ng/l vs 35.6 ng/l). Other findings for all patients included a higher peak exercise heart rate, and lower stroke volume (the amount of blood pumped in one contraction), and a small and not clinically significant drop in left ventricular ejection fraction (LVEF) for all patients after chemotherapy. These changes occurred in both groups.
I found this study interesting for many reasons. It supports my assumption that continuing to exercise with some level of intensity, ie running, while on chemotherapy, will help me to maintain my pre-treatment fitness. This kind of seems like a no brainer, but nice to see data to support it. And really interesting to see how this functional preservation translates into avoiding what might otherwise be like aging 15 years due to the effects of AC chemotherapy.
I was also very reassured to see that troponin levels in the blood were lower for the exercise group compared to the non-exercise group as this may be an indication that there may be a protective effect to the heart related to exercise. I also thought it was interesting that they noted that all subjects had a steeper rise in heart rate after chemotherapy. This is consistent with my own observations that my heart rate has been rising more rapidly and to a higher rate than I was accustomed to before I started chemotherapy.
There are weaknesses with this study though. The study is very small and therefore differences between the 2 groups could be just due to chance. The most significant weakness is that participants were allowed to choose which group to be in rather than being randomized. With this in mind, there were notable differences between the groups which could contribute to the findings. For example, the subjects in the group that chose standard of care were older, had higher baseline weight and lower baseline VO2max.
1. Adriamycin Package Insert.
2. Howden et al. Exercise as a diagnostic and therapeutic tool for the prevention of cardiovascular dysfunction in breast cancer patients. Europenan Journal of Preventative Cardiology. 2019, Vol. 26(3) https://doi.org/10.1177/2047487318811181