Patients with NSCLC Have Improved Survival If They Use Beta-blockers While Receiving Radiotherapy
Patients with non–small cell lung cancer (NSCLC) have improved survival outcomes if they are taking beta-blockers while receiving radiotherapy, according to a study of 722 patients recently published in Annals of Oncology.
Researchers at the University of Texas MD Anderson Cancer Center in Houston, Texas, reviewed the progress and outcomes of patients with NSCLC who had received definitive radiotherapy. They found that 155 patients who were on beta-blockers for other conditions, such as high blood pressure and heart disease, survived for an average of 23.7 months compared to the 567 patients who were not on beta-blockers, who survived for an average of 18.6 months—an improvement in survival of 22% after adjusting for other factors such as age, stage of the disease, whether or not chemotherapy was given concurrently, chronic obstructive pulmonary disease, and the use of aspirin.
Effect on Distant Metastasis
Beta-blocker use was also associated with improvements in distant metastasis-free survival and disease-free survival. Beta-blockers made no difference in locoregional progression-free survival for these patients.
"Our results suggest that the use of beta-blockers during radiotherapy may help to prevent the formation of metastases, and could lead directly or indirectly to improved care for patients with [NSCLC],” said Daniel Gomez, MD, Assistant Professor in the Department of Radiation Oncology at The University of Texas MD Anderson Cancer Center. “As far as we are aware, our study is the first analysis to show a survival benefit associated with the use of beta-blockers during definitive radiotherapy in patients with NSCLC. However, prospective studies are needed to investigate these findings further and to discover whether improved survival is affected by when and for how long patients need to take beta-blockers. We are excited about using our study as a starting point for further investigations."
The mechanism underlying the development of metastases is complex, but may involve chronic stress conditions and prolonged exposure to stress hormones. One of these hormones, norepinephrine, has been shown to stimulate the migration of tumor cells to other parts of the body. Receptors on the surface of cells, which beta-blockers are designed to inhibit, are involved in this process.
Zhongxing Liao, MD, from the Department of Radiation Oncology at MD Anderson, said, "Our findings agree with results from previous studies suggesting that beta-blockers have a specific effect on the cascade of events that lead to metastases. The fact that their use did not affect locoregional progression-free survival suggests that the drugs affect this metastatic cascade rather than the primary tumor."
Further Investigation Needed
Patients in the study had been treated with definitive radiotherapy from 1998 to 2010 at MD Anderson. The 155 patients on beta-blockers were taking a range of different types of the drug and at a range of doses depending on the medication and their need. The researchers said there were not enough patients in the study to discover whether the choice of beta-blocker might be important, but that most of the study patients who did well were on a selective beta-blocker. "This finding requires further investigation," said Dr. Liao.
She added, "Due to practical limitations, we were unable to assess whether any other medications that patients were taking while receiving radiotherapy may have influenced the results. This should be the subject of future analyses, ideally in clinical trials."
Dr. Gomez said the researchers were discussing the possibility of a clinical trial to investigate the efficacy of new treatments, such as beta-blockers, for lung cancer, but that this would require external funding. "Another future direction would be to examine further the molecular characteristics that lead to this apparent clinical improvement in survival. For instance, what cellular pathways are involved in patients that experience a benefit with beta-blockers, and can these mechanisms be altered in another way to achieve the same benefit?"
Source: The website of the National Cancer Institute
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