TREATMENT RELATED CARDIAC TOXICITY IN PATIENTS TREATED FOR BREAST CANCER Lawrence B. Marks Duke University Medical Center, Durham, NC E-mail: marks@radonc.duke.edu Radiotherapy (RT) plays an important role in the treatment of both early and late stage breast cancer. Because RT fields directed at the left breast/chest wall (¡À internal mammary nodes) typically incidentally include a portion of the heart, there is risk for RT-induced cardiotoxicity. Our initial prospective clinical trial (1998-2002) demonstrated that even with the use of modern radiation planning tools, left-sided chest wall/breast tangential photon therapy resulted in new perfusion defects in approximately 50-63% of women (these defects were identified using functional cardiac imaging with single photon emission computed tomography, SPECT, perfusion scans). The current study's aims and preliminary results are outlined below. 1. To define the temporal nature/persistence of perfusion defects: Amongst patients with a perfusion defect within two years following RT, 65% (11/17) had a persistent defect 3-5 years post RT. 2. To identify patient specific factors that may increase the risk of a perfusion defect: Overall, the rate of new perfusion defects is greater in African American patients than in Caucasian patients. The rates of perfusion abnormality among patients receiving and not receiving chemotherapy were similar. Using logistic regression to control for the dominant impact of irradiated heart volume, the rate of perfusion defects is higher for African Americans than for Caucasians (p=0.07); chemotherapy appeared not predictive (p=0.30). Body Mass Index (cut-point 25 kg/m2) was an independent predictor of perfusion defect(s); (p=0.004). 3. To relate perfusion changes to global function changes: New wall motion abnormalities are seen in approximately 12-34% of patients with a new perfusion defect vs. 0-8% of patients without defects (p = 0.001 - 0.37, depending on the post RT interval). Similarly, subtle changes in ejection fraction have been seen in patients, particularly those with more severe perfusion defects. Amongst patients studied 3-4 years post RT, 24% (9/38) had declines in ejection fraction exceeding 5%. Further, we have demonstrated the strong volume-dependence of RT-induced perfusion defects. Perfusion defects are seen in about 60% of patients who have at least 5% of the left ventricle in the field vs. < 20 % of patients with lesser volumes of irradiated left ventricle. In conclusion, RT appears to cause a volume-dependent reduction in regional cardiac perfusion. These perfusion defects largely persist beyond two years and are associated with corresponding abnormalities in wall motion and possibly reductions in ejection fraction. Specific factors such as Body Mass Index ¡Ý 25 kg/m2 and African American race, appear to be associated with an increased risk of RT-induced cardiac perfusion defects. An improved understanding of RT-induced heart disease¡ªits temporal nature, the impact of other clinical factors, and the relationship between perfusion and functional changes¡ª will help physicians care for and counsel patients who receive RT for breast cancer. The U.S. Army Medical Research and Materiel Command under DAMD17-02-1-0374 supported this Ann's NOTE: Cardiac toxicity is an area that complementary medicine will probably be able to impact. We respectfully suggest researchers look into CoQ10 and Traditional Chinese Medicine to name a few possibilities. Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.