This study resulted from NCCTG clinical trial N9831, from which breakthrough treatment findings were presented at ASCO 2005. "The original N9831 study showed that trastuzumab reduced the recurrence of HER-2 positive breast cancer about 50 percent," says Dr. Halyard, a radiation oncologist at Mayo Clinic Arizona and lead author of today's study. "We hoped also to show that trastuzumab did not add complications to radiation treatment, and the current study has certainly proven that, providing good news for many women."
About 25 percent to 30 percent of breast cancers produce an overabundance of a growth-promoting protein called human epidermal growth factor receptor (HER-2). These tumors tend to grow faster and are generally more likely to recur than tumors that do not overproduce HER-2. Trastuzumab is the first identified monoclonal antibody designed specifically to attack this overexpressed protein, and is used as a follow-on treatment to chemotherapy. A monoclonal antibody is a laboratory-engineered protein that helps the body's immune system fight foreign invaders such as cancer.
Dr. Halyard's study looked at the side effects related to adding trastuzumab to radiation therapy. In the 1,460 patients who received radiation in the original N9831 group, there was no significant difference in the incidence of skin reactions, pneumonitis, dyspnea, cough, esophageal dysphagia or neutropenia between those who received trastuzumab (908), and those who did not (552). Addition
Contact: Elizabeth Zimmermann