Bicalutamide 50mg or Chemo?

Hi Mistymoon, I’m sorry I can’t give you an answer because I just don’t know! I can, though, tell you that I really understand how you’re feeling. I think all of us wives/ loved ones experience more distress than is ever recognised - you are not alone in all of this - we are all with you on this journey and all hoping the menfolk get through this. Take care x

Prostap reduces his Testosterone to a low level. It might be worth asking for this Testosterone level to be measured, in case the Prostap isn't bringing it as low as expected, as there are alternatives to Prostap.

Bicalutamide is one of a family of anti-androgen drugs. (Androgen is the collective name for all male sex hormones, of which Testosterone is the best known, but there are many others too, similarly to Estrogen being the collective name for female sex hormones.) Anti-androgens are also a form of hormone therapy but they work differently - they don't stop Testosterone production, but instead they stop Testosterone use, by blocking the Androgen Receptors (ARs) that Testosterone and other Androgens would normally bind to in order to have their effect. Prostate cells have ARs, and Testosterone binding to them is what switches on the prostate cells, makes them generate PSA (which is the main product of the prostate, although it's not intended to get into the blood) and enables the cells to divide to generate more prostate cells.

When you're on Prostap or any of the other hormone therapy injections, this brings your Testosterone level low. This causes prostate cells to switch off, stop producing PSA and stop dividing/growing. However, a tiny number of the prostate cells have more ARs, and the low level of Testosterone can still switch those on. With most of the cells switched off, but just these very few cells with more ARs still able to grow, they will eventually become more significant, and this is when you start seeing PSA rise again while on hormone injections.

If you add in an anti-androgen such as Bicalutamide, this will block the ARs on prostate cancer cells, and stops even this small amount of remaining Testosterone from binding and switching them on. This is called a double blockade - blocking both the generation of Testosterone, and the use of Testosterone. Bicalutamide is cheap and is unlikely to give you any extra side effects if you're already on injections, so it might be worth a try. The downside is it doesn't tend to work for long, typically around 6 months, but very occasionally a couple of years. Many oncologists skip it because of this nowadays, but not all. Eventually the cancerous prostate cells learn to use the Bicalutamide instead of the Testosterone, and then your PSA will start rising again, so you have to stop using Bicalutamide. However, there's usually an interesting effect when you stop Bicalutamide under these conditions - your PSA falls again, because the prostate cells which had now started using Bicalutamide suffer what's known as anti-androgen withdrawal syndrome (AAWS). This may give you extra time after the failure of Bicalutamide before you need to start considering another treatment.

Bicaluatmide is the oldest anti-androgen still in common use. There are newer (and vastly more expensive) anti-androgen drugs which are more powerful than Bicalutamide, these being Enzalutamide, Daralutamide, and Apalutamide. Another drug which is similarly effective but works a different way is Abiraterone - it was similarly expensive, but the patent expired late last year and it's now much cheaper. Your oncologist has to apply for funding for these drugs, but may consider them for your treatment at some point. NICE rules that you are only allowed to be prescribed one of these expensive drugs during your treatment, and if that fails, you can't have another one of them (this restriction doesn't include Bicalutamide, but it's unlikely to work after any of the others have failed). These expensive drugs have been used instead of chemo. Chemo is a valuable tool in the arsenal though. It can't be used in men with various other conditions, so there can be some advantage to using it earlier while the man is healthy enough to have it. However, is has more side effects, and some can be permanent, which some people don't want to risk that early on. Also chemo can be used more than once during your treatment, which is not the case with the anti-androgen drugs as after they fail you aren't going to get any benefit using the same drug again.

Hi Andy, thank you for this! It’s an excellent explanation!