medwireNews: Among women with triple-negative breast cancer (TNBC), the use of beta blockers may improve BC-specific survival, suggests a population-based cohort study and meta-analysis.
“The biological reason behind the association between β-blocker use and improved prognosis for TNBC patients but not for other BC patients remains unclear,” say the study authors in the British Journal of Cancer.
“TNBC is more immunogenic than other subtypes of BC. As a consequence, TNBC may be more sensitive than other subtypes to restoration of anti-cancer immunity by treatment with β-blockers,” they speculate.
The team drew on linked national registries in Norway to identify 30,060 women aged 50 years or older at the time of being diagnosed with primary invasive BC during 2004–2018. Fifteen percent of these patients were considered beta blocker users (2% nonselective, 13% selective beta blockers) as they had filled a prescription in the 3 months prior to the BC diagnosis, while the remaining 85% were nonusers.
Over a median follow-up of 5.1 years, 9% of the study population had died due to BC, report Edoardo Botteri (Cancer Registry of Norway, Oslo) and co-researchers, adding that they found no significant association between beta blocker use and BC-specific survival in the overall cohort after adjusting for possible confounders, such as age, molecular subtype, year of diagnosis, and concomitant use of other medications.
However, when participants were stratified by molecular subtype, beta blockers were significantly associated with a reduced risk for BC-specific mortality among the 2087 patients with TNBC, at a hazard ratio (HR) of 0.66.
The association held true for both nonselective and selective beta blockers, with respective significant HRs of 0.24 and 0.71, leading the team to comment that “further mechanistic studies are needed to understand the role of the various receptor subtypes.”
There were no such significant associations between beta blocker use and BC-specific survival for the other molecular subtypes, such as luminal A or HER2-positive.
The results were backed up by a meta-analysis of 10 observational studies (including the current cohort) “that reported molecular subtype-specific estimates of the association between use of β-blockers and BC prognosis,” say Botteri and colleagues.
The meta-analysis showed that in patients with TNBC, there was a significant correlation between beta blocker use and progression- or recurrence-free survival, such that the risk for a progression or recurrence event or death was 42% lower with versus without beta blockers.
Similarly, the risk for BC-specific mortality was reduced by a significant 26% for TNBC patients who took beta blockers compared with those who did not.
And once again, no such associations were observed for the other molecular subtypes.
“These findings may reconcile inconsistent results that have been found across a growing number of studies that reported on use of β-blockers and prognosis in BC cohorts,” conclude Botteri et al.
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