Are beta-blockers on the therapeutic horizon for ovarian cancer treatment?

Prospective pilot trial with combination of propranolol with chemotherapy in patients with epithelial ovarian cancer and evaluation on circulating immune cell gene expression

OBJECTIVE

To determine the feasibility of pharmacologic beta-adrenergic blockade in women with newly diagnosed stage II-IV epithelial ovarian cancer (EOC) throughout primary treatment.

METHODS

Patients initiated propranolol prior to beginning chemotherapy or surgery. Feasibility was assessed as proportion able to complete 6 chemotherapy cycles while on adrenergic suppression. Descriptive statistics summarized surveys, and paired changes were analyzed using signed rank tests. Random-intercept Tobit models examined immune response.

RESULTS

Median age was 59.9; 88.5% were stage IIIC/IV; and 38.5% underwent primary debulking. Thirty-two patients were enrolled; 3 excluded because they never took propranolol; an additional 3 didn't meet inclusion criteria, leaving 26 evaluable. Eighteen of 26 (69%), 90% credible interval (CI) of 53-81%, completed 6 chemotherapy cycles plus propranolol (an 82% posterior probability that the true proportion of success is ≥60%). Among the 23 patients with baseline and six month follow up data, overall QOL, anxiety, and depression improved (P < 0.05) and leukocyte expression of pro-inflammatory genes declined (P = 0.03) after completion of therapy. Decrease from baseline of serum IL-6 and IL-8 preceded response to chemotherapy (P < 0.0014). Change from baseline IL-10 preceded complete response.

CONCLUSION

Use of propranolol during primary treatment of EOC is feasible and treatment resulted in decrease in markers of adrenergic stress response. In combination with chemotherapy, propranolol potentially results in improved QOL over baseline.

Impact of beta blockers on survival outcomes in ovarian cancer: a nationwide population-based cohort study

Objective

The impact of beta blockers (BBs) on survival outcomes in ovarian cancer was investigated.

Methods

By using Korean National Health Insurance Service Data, Cox proportional hazards regression was performed to analyze hazard ratios (HRs) with 95% confidence intervals (CIs) adjusting for confounding factors.

Results

Among 866 eligible patients, 206 (23.8%) were BB users and 660 (76.2%) were non-users. Among the 206 BB users, 151 (73.3%) were non-selective beta blocker (NSBB) users and 105 (51.0%) were selective beta blocker (SBB) users. BB use in patients aged ≥60 years, longer duration use (≥1 year), in patients with Charlson Comorbidity Index (CCI) ≥3, and in cardiovascular disease including hypertension was associated with better survival outcome. These findings were observed in both NSBB and SBB. When duration of medication was analyzed based on number of days, NSBB (≥180 days) was associated with improved overall survival (OS) with a relatively shorter period of use compared to SBB (≥720 days). In multivariate Cox proportional hazards model, longer duration of BB medication (≥1 year) was an independent favorable prognostic factor for both OS and disease-specific survival in ovarian cancer patients.

Conclusion

In our nationwide population-based cohort study, BB use was associated with better survival outcomes in ovarian cancer in cases of long term duration of use, in older patients, and in cardiovascular and/or other underlying disease (CCI ≥3).

Carvedilol inhibits EGF-mediated JB6 P+ colony formation through a mechanism independent of adrenoceptors

Carvedilol is reported to prevent cancers in humans and animal models. However, a molecular mechanism has yet to be established, and the extent to which other β-blockers are chemopreventive remains relatively unknown. A comparative pharmacological approach was utilized with the expectation that a mechanism of action could be devised. JB6 Cl 41-5a (JB6 P+) murine epidermal cells were used to elucidate the chemopreventative properties of β-blockers, as JB6 P+ cells recapitulate in vivo tumor promotion and chemoprevention. The initial hypothesis was that β-blockers that are GRK/β-arrestin biased agonists, like carvedilol, are chemopreventive. Sixteen β-blockers of different classes, isoproterenol, and HEAT HCl were individually co-administered with epidermal growth factor (EGF) to JB6 P+ cells to examine the chemopreventative properties of each ligand. Cytotoxicity was examined to ensure that the anti-transformation effects of each ligand were not due to cellular growth inhibition. Many of the examined β-blockers suppressed EGF-induced JB6 P+ cell transformation in a non-cytotoxic and concentration-dependent manner. However, the IC₅₀ values are high for the most potent inhibitors (243, 326, and 431 nM for carvedilol, labetalol, and alprenolol, respectively) and there is no correlation between pharmacological properties and inhibition of transformation. Therefore, the role of α1- and β2-adrenergic receptors (AR) was examined by standard competition assays and shRNA targeting β2-ARs, the only β-AR expressed in JB6 P+ cells. The results reveal that pharmacological inhibition of α1- and β2-ARs and genetic knockdown of β2-ARs did not abrogate carvedilol-mediated inhibition of EGF-induced JB6 P+ cell transformation. Furthermore, topical administration of carvedilol protected mice from UV-induced skin damage, while genetic ablation of β2-ARs increased carvedilol-mediated effects. Therefore, the prevailing hypothesis that the chemopreventive property of carvedilol is mediated through β-ARs is not supported by this data.

The Clinical Relevance of Beta Blockers in Ovarian Carcinoma: A Systematic Review

The last ten years have seen hardly any improvement in the prognosis of ovarian carcinoma. There is a great need for new treatment strategies, and a recent retrospective study showing a survival advantage with the use of beta blockers met with a very positive response. This systematic review summarizes the current state of knowledge and research on the topic: A database analysis identified six clinical studies showing inconsistent results with respect to the administration of beta blockers and disease course. The 13 preclinical studies identified showed almost without exception both that catecholamines had detrimental effects on tumour progression, and that these effects could be influenced by pharmacological blockade. Overall the available evidence does not justify the use of beta blockers in clinical practice for ovarian carcinoma at the present time. This article also outlines details of research design required for further studies needed on the subject. Preclinical research findings are however very impressive: They not only form an important basis for the development of future clinical studies but also, through revealing new pathomechanisms, they already make an important contribution towards the development of new treatment strategies for ovarian carcinoma.

Beta blockers and cancer prognosis - The role of immortal time bias: A systematic review and meta-analysis

BACKGROUND

Findings from experimental and observational studies have suggested beneficial effects of beta blocker (BB) use on cancer survival. Nevertheless, results have been inconclusive and there have been concerns that the observed associations might have resulted from immortal time bias (ITB). We conducted a systematic review and meta-analysis to summarize existing evidence, paying particular attention to this potential source of bias.

METHODS

A systematic literature search was performed in PubMed and Web of Science. Studies investigating the association between BB use and overall or cancer-specific survival were included. Summary estimates were derived from meta-analyses using random effects models. The potential influence of ITB was investigated.

RESULTS

We identified 30 eligible studies including 88,026 cancer patients in total. We deemed 11 studies to be at high or unclear risk of ITB. Including all studies in the meta-analysis, BB users had a significantly better overall (hazard ratio (HR) 0.88, 95% CI 0.79-0.97) and cancer-specific (HR 0.75, 95% CI 0.64-0.88) survival. Excluding the studies deemed to be prone to ITB resulted in HRs (95% CIs) of 1.00 (0.93-1.07) and 0.90 (0.83-0.98), respectively. Analyses on cancer site and BB type did not show beneficial associations besides overall survival among melanoma patients. However, melanoma-specific survival was not improved.

CONCLUSION

We found no clinically meaningful evidence for an association between BB use and survival after excluding studies with a possible ITB. Our results support suggestions that the proposed beneficial effect of BBs on cancer survival might be based on ITB.