Two studies indicate that older women with trastuzumab-treated breast cancer and those who undergo radiation to the left chest wall may be at risk for increased rates of cardiotoxicity.

Two independent research groups have identified resistance mutations in the gene that encodes the estrogen receptor in some cases of metastatic breast cancer.

Patients with early-stage breast cancer who received radiation therapy had a higher risk of heart disease, due to the exposure of their heart tissue to the treatment, according to a 48-patient study by Columbia University.