Intermittant chemo

[Stoneartist]

I have my next meeting with the onkologist tomorrow and will sound him out on the way forward. I expect a further PSA reduction value due to ongoing Xtandi 120mg treatment. But while all tumours are at a low ebb I am thinking of zapping whats there while it is in retreat (last PSA= 0.6). I am going to ask him about doing more chemo (Docetaxel) in intermittant sessions - for example one session every 4 months. Havnt found too much literature on that yet (more on other cancers) - am going to ask what he thinks. Also I will be asking about reducing Xtandi to 80mg and see if things (PSA) still goes down or remains stable.

Any input on these matters from you experts out there ???

[Tall_Allen]

Bad idea on Xtandi reduction. You are making a common mistake of thinking the PSA is the cancer -- it's not, it's just a biomarker. Your PSA might be undetectable on Lupron alone -- that doesn't matter. What matters is which therapy keeps you progression-free and alive longest.

Also a bad idea to have chemo when your cancer cells are not actively growing. Chemo kills your most actively growing cells (cancerous and non-cancerous). Using chemo when your cancer is dormant only gives side effects without any oncological benefit.

If you want to zap some of your larger metastases, and they are in a place where it is completely safe to put radiation, why not? There is no known benefit, however.

[Stoneartist in reply to Tall_Allen]

Thanks TA. I guess the first thing I have to do is to see if any of the metastasis are large enough to be seen. It seems my cancer - both the initial and the castrate resistant cancer have a high PSA expression so at the moment PSA going down is a good sign. (I have a new PSA value tomorrow)The Xtandi reduction idea comes from the thought that 160mg of Xtandi takes me over saturated, and although this attacks and kills the tumours I may not need so much to just keep them dormant. I think most of the clinical trials have focused on reducing tumour growth as monitored by PSA. Also, since I still have my prostate I dont expect to reach undetectable PSA - but it will still be interesting to monitor it.

The chemo and dormant cells you have mentioned before and I agree there. What I am thinking is that there may be a benefit from intermittent chemo to zap any cancer cells that have started growing but are not evident on PSA or scans yet. My oncologist says the next step is chemo when the PSA starts rising again, and I had very few side effects from my chemo in 2020. The clinical trials on intermittent Docetaxel also use PSA boundaries as start and stop points. I cant find anything relevant to intermittent docetaxel as a preventative treatment - aimed at the growth period before we can see it on scans and PSA.

I will probably continue with SOC - but I am inquisitive as to the "all-or nothing" approach seen in the clinical trials, where dosage seems usually adjusted due to side effects and not efficacy.

[Tall_Allen in reply to Stoneartist]

Resist the urge to tinker. The clinical trials that showed the benefit of Xtandi used survival as its primary endpoint. Docetaxel does not prevent prostate cancer. In fact, it has been shown to have no benefit if used too early:

prostatecancer.news/2019/02...

[Stoneartist in reply to Tall_Allen]

Excellent summary on your link TA. I will have to go back in the think tank !!!

Thanks

[dhccpa in reply to Tall_Allen]

TA, you say PSA may be undetectable on Lupron alone but it's progression that counts. What's the best way to track progression when PSA is very low or undetectable? A particular scan or something else? Thanks.

[Tall_Allen in reply to dhccpa]

Scans may show progression, and are definitive.

[dhccpa in reply to Tall_Allen]

Which scans are best, though, with very low PSA? Some have posted that with low PSA PET scans won't detect anything.

[Tall_Allen in reply to dhccpa]

They usually won't at low PSA.