Breast cancer is the most common cause of cancer death among women. Targeting the vascular endothelial growth factor (VEGF), a key molecule in the growth of blood vessels in tumors, is one promising approach to treating metastatic breast cancer. At present, trials of drugs that target VEGF are limited to bevacizumab (Avastin).
Yet, according to a systematic review by Cochrane researchers, bevacizumab offers only a modest benefit in delaying disease progression in patients with advanced-stage breast cancer. Moreover, the researchers found no overall survival benefit when adding bevacizumab to chemotherapy, an established cancer treatment in this indication.
For the study, researchers gathered evidence from 7 trials involving a total of 4032 patients, most of whom had metastatic breast cancer. When assessing the clinical value of bevacizumab in combination with established chemotherapy drugs, the researchers found that time to tumor progression or death increased by between 1 and 6 months, depending on the chemotherapy drugs prescribed. However, adding bevacizumab to first- or second-line treatments did not increase overall survival or quality of life, according to researchers.
“At best, adding bevacizumab to standard chemotherapy appears to offer a modest benefit for those with metastatic breast cancer,” said lead researcher, Anna Dorothea Wagner, of the Fondation du Centre Pluridisciplinaire d’Oncologie, University Hospital Lausanne, Switzerland. “Whether it can truly be of benefit to the patient is debatable, because it only briefly prolongs [the time to] progression of the disease. No impact on the patient’s overall survival or quality of life has been demonstrated.”
The researchers believe that clinical trials testing innovative drugs for advanced-stage breast cancer treatment should monitor patients until death. This would allow for greater understanding of the impact new treatments have on survival.
In 2011, the FDA removed breast cancer from indications on the label of bevacizumab due to concerns about serious side effects and doubts about its benefit in terms of overall survival.
Source: Wiley.