Trastuzumab significantly improves the long-term survival of HER-2 positive breast cancer patients, according to a large national study published in the Journal of Clinical Oncology (2014; doi:10.1200/JCO.2014.55.5730).
The study was designed to determine the long-term safety and efficacy of trastuzumab (Herceptin), which is primarily used alongside chemotherapy to treat HER2-positive breast cancer. The study focused on both the overall survival rates of patients up to 10 years posttreatment as well as the known and potentially harmful side effects to the cardiac system.
The study found that trastuzumab, when added to chemotherapy, improved 10-year survival from 75% with chemotherapy alone to 84% with the addition of trastuzumab. In addition, results also demonstrated continued improvement of survival without cancer recurrence, as the 10-year disease-free survival rate increased from 62% to 74% when trastuzumab is added to treatment.
Although heart problems are recognized side effects of trastuzumab, the incidence of such events was found to be approximately 3% and the majority of those patients recovered from the initial effects.
“We have found that when Herceptin is used in combination with chemotherapy, a patient’s survival is significantly improved,” said Charles E. Geyer Jr, MD, a physician-researcher at Virginia Commonwealth University Massey Cancer Center in Richmond. “There are minimal long-term side effects, and the likelihood of the cancer recurring is greatly reduced.”
The study was designed to provide much needed long-term efficacy data on trastuzumab, which is a proven effective treatment, but one without much information on the role it plays in patients’ long-term survival. The study combines data from two trials: NSABP B-31, led by the National Surgical Adjuvant Breast and Bowel Project (NSABP), and NCCTG N9831, led by the North Central Cancer Treatment Group (NCCTG).
Each trial was designed independently to analyze overall survival rates of patients with early-stage HER2-positive breast cancer. The study specifically addressed whether or not the patient experienced a cancer recurrence and if there were any harmful side effects that would diminish favorable treatment results.
Additional trials are currently underway to try to improve patient outcomes by using trastuzumab in combination with various other drugs that also specifically target breast cancers with overexpressed HER2 proteins. Other trials are investigating applications of trastuzumab for different cancers. For example, one study is presently investigating whether or not patients with breast cancers with lower amounts of HER2 protein might also benefit from trastuzumab.