By Lynda Williams, Senior medwireNews Reporter
Beta blockers may boost survival in patients undergoing definitive radiotherapy for non-small-cell lung cancer (NSCLC), suggests research published in the Annals of Oncology.
Analysis shows that the 155 NSCLC patients given incidental beta blockers had significant better distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival than the 567 patients who were not given the agents.
However, beta blocker use had no impact on locoregional progression-free survival (LRPFS), leading the researchers to suggest that "the drugs may be affecting the tumor metastatic cascade rather than affecting the primary tumor."
The team investigated the impact of beta blockers on newly diagnosed NSCLC patients at the MD Anderson Cancer Center between 1998 and 2010 following reports that norepinephrine may stimulate tumor cell migration - a process could be targeted via the beta-adrenergic receptor.
Beta blocker use significantly predicted longer DMFS (hazard ratio [HR]=0.67), DFS (HR=0.74), and OS (HR=0.78), after adjusting for confounders including age, cancer stage, histology, tumor volume, Karnofsky performance score, use of concurrent chemotherapy, and radiation dose. Other factors including presence of hypertension or chronic obstructive pulmonary disease, and use of aspirin were also considered in the multivariate analysis.
The researchers note that 68% of patients were given beta blockers for hypertension. The remaining patients were given beta blockers for nonhypertensive disorders such as coronary heart disease.
Most patients were given selective (β1) beta blockers such as metoprolol (n=89) and atenolol (n=43). Just 21 of the patients were given nonselective agents, such as carvedilol.
This indicates that β1 is the primary beta-adrenergic system active in pulmonary adenocarcinoma, say Z Liao (The University of Texas MD Anderson Cancer Center, Houston, USA) and co-authors.
"Indeed, our results thus suggest that the β1 pathway is important in reducing the probability of distant dissemination and thus DFS and OS in clinical settings," they write.
However, the team cautions that "it is also the case that even 'selective' β-blockers used clinically have cross activity and some β1-antagonists are more β2 selective in certain settings."
Liao et therefore conclude: "Future prospective trials are needed to validate these retrospective findings and establish whether the length and timing of beta-blocker use influence survival outcomes."
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