Thursday, March 14, 2013

Your Heart: After Cancer

Important information about chest radiation and heart disease.

We have warned about this in the past, but a new study confirms earlier ones.

Bottom line: Keep an eye on your cholesterol, it elevates after chemotherapy; exercise at least 5 times a week; keep your weight down. Make sure you have your cholesterol checked when you go to your oncologist (since you probably see that doc more than any other one)


Background

Radiotherapy for breast cancer often involves some incidental exposure of the heart to ionizing radiation. The effect of this exposure on the subsequent risk of ischemic heart disease is uncertain.

 

Methods

We conducted a population-based case–control study of major coronary events (i.e., myocardial infarction, coronary revascularization, or death from ischemic heart disease) in 2168 women who underwent radiotherapy for breast cancer between 1958 and 2001 in Sweden and Denmark; the study included 963 women with major coronary events and 1205 controls. Individual patient information was obtained from hospital records. For each woman, the mean radiation doses to the whole heart and to the left anterior descending coronary artery were estimated from her radiotherapy chart.


Results: 

The overall average of the mean doses to the whole heart was 4.9 Gy (range, 0.03 to 27.72) Rates of major coronary events increased linearly with the mean dose to the heart by 7.4% per gray (95% confidence interval, 2.9 tp 14.5 with no apparent threshold.


The increase started withing the first 5 years after radiotherapy and continued into the third decade after radiotherapy. The proportional increase in the rate of major coronary events per gray was similar in women with and women without cardiac risk factors at the time of radiotherapy.

Conclusions

Exposure of the heart to ionizing radiation during radiotherapy for breast cancer increases the subsequent rate of ischemic heart disease. The increase is proportional to the mean dose to the heart, begins within a few years after exposure, and continues for at least 20 years. Women with preexisting cardiac risk factors have greater absolute increases in risk from radiotherapy than other women. (Funded by Cancer Research UK and others.)

Supported by funding to the Oxford University Clinical Trial Service Unit from Cancer Research UK, the British Heart Foundation, and the U.K. Medical Research Council and by grants from the European Commission (FI6R-012796), the U.K. Department of Health (RRX 108), the British Heart Foundation Centre for Research Excellence (CRE RE/08/004, to Dr. Cutter), and the Oxford National Institute for Health Research Biomedical Research Centre (to Dr. Rahimi).

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
No potential conflict of interest relevant to this article was reported.
We thank research nurses Ann-Sofie Andersson and Milka Krestelica in Sweden and Liselotte Jeppesen in Denmark for data abstraction; and Ulrich H. Koehler in Denmark for data management.

Source Information

From the Clinical Trial Service Unit (S.C.D., P.M., D.C., R.P., C.T.) and the George Centre for Healthcare Innovation (K.R.), University of Oxford, Oxford, and the Department of Medical Physics, Royal Surrey County Hospital and Surrey University, Guildford (A.N.) — both in the United Kingdom; the Department of Oncology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense (M.E.), the Oncology Department, Aalborg Hospital, Aalborg (D.B.), and the Danish Breast Cancer Cooperative Group, Rigshospitalet, Copenhagen (M.-B.J.) — all in Denmark; the Department of Medical Epidemiology and Biostatistics (A.M.B., P.H.) and the Division of Cardiovascular Epidemiology, Institute of Environmental Medicine and Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyd Hospital (B.G.), Karolinska Institutet, and the Departments of Oncology (U.B.-G.) and Medical Physics (G.G.), Karolinska University Hospital — all in Stockholm; and the H. Lee Moffitt Cancer Center and Research Institute, University of Southern Florida, Tampa (C.C.).
Address reprint requests to Dr. Darby at the Clinical Trial Service Unit, Richard Doll Bldg., Old Road Campus, Oxford OX3 7LF, United Kingdom, or at .

1 comment:

Kristin King said...

This is good information to know. Thanks!