MORBIDITY OF ISCHEMIC-HEART-DISEASE IN EARLY BREAST-CANCER 15-20 YEARS AFTER ADJUVANT RADIOTHERAPY

Purpose: To assess the cardiac side effects, primarily the occurrence of ischemic heart disease in symptom-free patients with early breast cancer treated with radiotherapy. Methods and Materials: Thirty-seven survivors of a former randomized study of early breast cancer were examined. Twenty patients irradiated pre- or postoperatively for left sided disease (study group patients) were compared with 17 controls who were either treated for right sided disease, or were nonirradiated patients. Radiotherapy was randomized in the original study; either tangential field Co-60, or electron-therapy was delivered. Echocardiography and bicycle ergometry stress test with Tc-99m SestaMIBI myocardial perfusion scintigraphy mere carried out and the patients' major risk factors for ischemic heart disease were also listed. Results: Our results showed a significant difference between the scintigraphic findings of the two groups. Five of the 20 study group patients (25%), while none of the 17 controls exhibited some kind of significant defects on scintigraphy, indicating ischemic heart disease (p < 0.05). No deterioration in left ventricular systolic and/or diastolic function could be detected by echocardiography. Conclusion: Radiotherapy for left sided breast cancer with the mentioned treatment technique may present as an independent risk factor in the long-term development of ischemic heart disease, while left ventricular dysfunction could not be related to the previous irradiation. We emphasize the need to optimize adjuvant radiotherapy for early breast cancer by considering the dose both to the heart as well as the cancer.