This may be of interest to some.
Plot Twist
The team, led by Professor Samuel Denmeade from Johns Hopkins University in the US, enrolled 16 patients with castration-resistant prostate cancer onto their study. They found that in some patients, drug-resistance could be reversed by first boosting levels of testosterone to far beyond what’s normally seen in the body, before dropping testosterone levels again. For some men it was like hitting a reset button and they responded to castration drug therapy again.
The men received treatments that switched their testosterone levels from high to low over a four week period – something the researchers dub ‘bipolar androgen therapy’. And this treatment cycle was repeated three times.
Of the 16 patients enrolled in the study, 14 men completed these three cycles and were monitored further. The team analysed levels of the blood marker PSA, which can be used as an indicator of how the disease is progressing (although there are some well documented challenges that come with using this marker).
The new treatment approach produced a notable decrease in PSA levels in half of the patients (seven out of 14), suggesting that the tumour cells may be responding to the treatment. Ten of the men also had secondary tumours that could be picked up by CT scan, and half of these patients saw those tumours shrink following the bipolar therapy.
Interestingly, 10 out of 10 patients who were suitable for follow up after they completed bipolar therapy saw their PSA levels fall again when the hormone therapy that they used to be resistant to was reintroduced. And the researchers believe that this re-sensitisation to treatment could be a promising avenue for further research.
But this new approach goes against pretty much everything we generally know about prostate cancer.
Prostate cancer cells thrive on testosterone. So on paper it doesn’t really make sense to load up the body with more of what fuels tumour growth. That would be like throwing a grenade at a house that’s on fire. Surely it can only make things worse?
But this new study complements recent research showing that tumour cells that are used to low levels f testosterone can be killed by a surprise high dose of the hormone. Researchers believe this may be down to the unexpected increase in the hormone stopping the cancer cells’ ability to copy their DNA. And it may also trigger catastrophic breaks in cells’ DNA, causing them to die.
But further, larger scale studies will be required to confirm this.
“This is major new hope,” says Professor Charlotte Bevan, a UK based prostate cancer expert from Imperial College London. The men can start re-taking their hormone therapy, that they were previously resistant too, which, according to Professor Bevan is “the best case scenario”.
“However, no one is saying this isn’t a risky strategy,” she adds.
http://scienceblog.cancerresearchuk.org/2015/01/27/the-latest-plot-twist-in-the-treatment-of-prostate-cancer/
Roy
Edited by member 27 Mar 2015 at 10:47
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