By Jimmy Downs

Wednesday Nov 7, 2012 (foodconsumer.org) -- Using a breast cancer drug, either cardiotoxic or non-cardiotoxic, can raise risk of heart disease, according to a study in Pharmacoepidemiology and Drug Safety.

M. U. Yood of Department of Epidemiology, Boston University School of Public Health in Boston, MA, USA and colleagues conducted the study and found that of advanced breast cancer patients,16 percent of those who used any cardiotoxic breast cancer drug experienced heart failure events during a 3-year  follow-up.

The authors also found that of those with advanced breast cancer patients who used any breast cancer drug that was non-cardiotoxic, 8 percent experienced heart failure events during the three-year follow-up.

The study was based on data from all women identified from a Midwestern health system who were diagnosed with stage III/IV breast cancer between 1995 and 2003 and 50 women initially diagnosed with stage I/II who later progressed to stage II/IV breast cancer.

For the study,  researchers calculated the rates of cardiovascular disease/events including heart failure, dysrhythmia and ischemia events among patients used either cardiotoxic breast cancer drug s (anthracycline or trastuzumab) and non-cardiotoxic drugs. 

It was found that of 315 breast cancer patients, 90.5 percent used a breast cancer drug and 67.7 percent took cardiotoxic breast cancer drugs. Fewer older patients received cardiotoxic breast cancer drugs than younger patients.

After adjustment for potential risk factors including age, race, stage, surgery/radiation, estrogen receptor/progesterone receptor status, and year at diagnosis, a 150 percent higher rate of new cardiac events was found in patients who took any cardiotoxic breast cancer drug, compared with those taking non-cardiotoxic drugs. 

Patients who received a non-cardiotoxic breast cancer drug were 220 percent more likely to have cardiac event history and 490 percent more likely to have heart failure history.  This may suggest that patients with cardiac problems were more often given a less risky breast cancer drug.

The researchers also found "patients with cardiac comorbidity are less likely to receive cardiotoxic agents."

The researchers concluded "Use of cardiotoxic agents is common; treatment is related to patient and tumor characteristics and is associated with substantial risk of cardiotoxicity that persists during patients' remaining lifespan."