I take propranolol every day for essential tremor and have for years, so I've followed the beta-blocker/PC connection with interest. Unfortunately, the data so far are equivocal:
/link.springer.com/article/10.1007%2Fs10552-015-0693-2www.ejcancer.com/article/S0959-8049(14)00885-5/abstract/www.ncbi.nlm.nih.gov/pmc/articles/PMC4425323/www.sciencedirect.com/science/article/pii/S0302283813000109/www.ncbi.nlm.nih.gov/pmc/articles/PMC4504645/The effect, if any, seems to be small. It is very hard to draw any useful conclusions from these kinds of retrospective, non-controlled studies. Men who take beta blockers almost always also take statins and aspirin as well.
If there is any value, the proposed mechanism is interesting. Lab studies suggest that any benefit may be limited to early stages of PC progression. In later metastatic stages, the parasympathetic nervous system (with acetylcholine rather than norepinephrine as the neurotransmitter) becomes instrumental to progression. If this is true, then propranolol may have some effect while the cancer is still localized, but not after it has metastasized, and may account for the equivocal findings. Looking at my anecdotal experience, it clearly had no benefit for me in preventing my early stage PC.
/www.ncbi.nlm.nih.gov/pmc/articles/PMC3925654/There is a clinical trial in the works if you are interested:
/clinicaltrials.gov/ct2/show/NCT02944201BTW - I hate taking them!