GSPECT-CT myocardial scintigraphy plus calcium scores as screening tool for prevention of cardiac side effects in leftsided breast cancer radiotherapy.

PURPOSE To use gated (G) 99mTc-Tetrofosmin single photon emission computed tomography (SPECT)-CT combined with coronary calcium (Ca) scores to assess and differentiate patients with left-sided breast cancer, after surgery and doxorubicin (DOX)-based chemotherapy and who had cardiac risk factors and needed to adapt radiotherapy (RT) in order to prevent cumulative cardiac side effects caused by RT. METHODS Included were 28 female patients (mean age 49±16 years) with asymptomatic left-sided breast cancer, one month after DOX-based chemotherapy (mean 522±36mg) and before RT. A group of 18 patients (study group) with cardiovascular risk factors was included, while a group of 10 patients with no cardiovascular risk factors served as control. 99mTc-Tetrofosmin GSPECT-CT with Ca scores on Symbia T16 (Siemens Medical Solutions Inc, USA), using standard stress protocol was performed. QGS/QPS quantitative analysis of the myocardial perfusion and function was used. RESULTS 26 patients had normal perfusion images based on QPS. Hypoperfused defects with mild hypoperfusion and slightly increased Ca scores had 2 (11%) patients from the study group and no patient in the control group: the 2 patients were determined as having coronary atherosclerosis and silent coronary artery disease. Twenty three patients had normal parameters based on QGS. Diastolic and segmental dysfunction had 4 (14%) patients from the study group and one (4%) patient from the controls, determined as caused by chemotherapy-induced cardiotoxicity. Very high hazard for cardiac damage if standard RT was to be performed had 6 (21%) patients in the study group and one (4%) from the controls. These patients received RT, in order to prevent cardiac damage. CONCLUSION 99mTc-Tetrofosmin GSPECT-CT plus Ca scores provide combined cardiac assessment and can serve as a reliable screening method to prevent cardiac damage caused by RT in left-sided breast cancer patients, who have cardiac risk factors and have been administered DOXbased chemotherapy.