Cardio-oncology or Onco-cardiology? Take your Pick

The introduction to an article I read recently sums up a new reality: “Current oncologic treatments have brought a strong reduction in mortality in cancer patients. However, the cancer-therapy related cardiovascular complications, in particular chemotherapy and radiation therapy-induced cardiotoxicities, are a major cause of morbidity mortality in people living with or surviving cancer.”¹ Some of the culprits-anthracyclines, HER2-targeted therapy for breast cancer, and tyrosine kinase inhibitors-have been around a while.¹ A more recent addition to the chemotherapy armamentarium for cancer-the immune checkpoint inhibitors (ICIs)-deserve extra attention from the cardiology community.² These agents are undergoing an extensive marketing push through television advertising.

The ICIs amplify T-cell mediated immune responses against cancer cells.² Clinical trials have demonstrated positive results against advanced melanoma, non-small cell lung cancer, renal cell carcinoma, head and neck cancer, urothelial cancer, and Hodgkin disease.² That said, the cardiovascular complications can be severe. Eighteen cases of myocarditis occurred among 20 594 individuals treated with ICIs; incidence was higher in patients receiving 2 ICIs simultaneously.² The even more worrisome statistic is that 50% of the patients with myocarditis died.²  Myasthenia gravis accompanied myocarditis in some of these patients.²

The continuum of cardiac danger does not end there. Pericarditis, with or without myocarditis, is also a complication of ICI therapy.² The pericardial inflammation has led to tamponade physiology. Left ventricular fibrosis and failure have been described as has Takotsubo syndrome.² Arrhythmias were common with ICI treatment including atrial fibrillation, ventricular tachycardia or fibrillation, and heart block. A database for cardiovascular complications reported with ICIs suggests that toxic effects on the heart seem to be increasing.²

Investigation into the mechanism underlying these cardiovascular toxicities is ongoing but there is still little evidence-based guidance for monitoring and managing such patients. Should cardiovascular disease be treated in a cancer survivor as it is in patients with chronic diseases such as diabetes and hypertension?¹ Not always. Even though the interdisciplinary area of cardio-oncology has continued to grow more sophisticated over the past 20 years,¹ the chemotherapies and their collateral damage have as well. We need to match pace with our vigilance.

References:

1. Han X, Zhou Y, Liu W. Precision cardio-oncology: understanding the cardiotoxicity of cancer therapy.  NPJ Precis Oncol. 2017;1:31. doi: 10.1038/s41698-017-0034-x. eCollection 2017
2. Lyon AR, Yousaf N, Battisti NML, Moslehi J, Larkin J. Immune checkpoint inhibitors and cardiovascular toxicity. Lancet Oncol. 2018;19:PE447-E458.