THE BEGINNINGS OF CARDIO-ONCOLOGY

The 14th March issue of the New England Journal of Medicine carried an important piece of work by the researchers at Karolinski Institute, Stockholm. Dr Per Hall ( lead investigator ) and his group looked into females with Ca Breast who had received radiotherapy, and followed them up for about 40 years. as we all know, the Swedish health system is one of social insurance and so patient follow-up data was complete. They enrolled, between 1958-2001 2168 females with the diagnosis of Ca Breast and who had radiotherapy to the left breast. They followed them up and found that there were 963 major cardiac events ( including MIs, revascularisations or cardiac death ), giving an event rate of 44%. They found that most of the events occured within 5 years of radiation, but could occur as far out as 30 years of the radiation. Of course the incidence of cardiac events is higher if there are other important coronary risk factors and also if patients had coronary events prior to DXT. The radiation dose is also important. The average dose associated with an event was about 4.9Gy, and there was a 7.4 % incease risk of a coronary event for every 1 Gy increase in dose. Of course radiation of the left breast had a higher risk of coronary events. The coronary event rates were not affected by the chemotherapy. Besides, coronary events, left breast radiation was also corelated with increase incidence of pericarditis, peripheral vascular disease, arrhythmias,  cardiomyopathy, and also some valvular heart disease.
This article concludes by saying that although it is important to have radiation as an important treatment modality for Ca Breast, oncologist must be aware of the cardiac risk, especially in someone who had a recent MI and should tailor their treatment strategy accordingly, and perhaps work with a cardiologist on such patients.
Are we seeing the beginning of a new subspecialty of Cardio-oncology?