Prostate cancer blood test 'helps target treatment'

Evrard Martin
Juin 19, 2017

By testing cancer DNA in the bloodstream, researchers from Institute of Cancer Research in the United Kingdom found they could pick out which men with advanced prostate cancer were likely to benefit from treatment with new drugs called PARP inhibitors.

They also used the test to analyse DNA in the blood after treatment had started, so people who were not responding could be identified and switched to alternative therapy in as little as four to eight weeks.

The same test was also used to pick up signs of evolving cancer showing the first signs of drug resistance.

Opening the door to precision medicine for prostate cancer, researchers have developed a three-in-one blood test that could tell which men would benefit from a class of new drugs, detect early signs of resistance and monitor cancer's evolution over time.

Researchers from The Institute of Cancer Research and the Royal Marsden NHS Foundation Trust said the test could help target treatment better and also reduce its side effects.

"We think it could be used to make clinical decisions about whether a PARP inhibitor is working within as little as four to eight weeks of starting therapy", he said.

'Not only could the test have a major impact on treatment of prostate cancer, but it could also be adapted to open up the possibility of precision medicine to patients with other types of cancer as well'.

Other previous studies have also found that various chemicals found in foods such as turmeric, apple peels and green tea could potentially be beneficial in helping to ward off cancer, by minimising one of the risk factors for disease, inflammation within the body.

The new test was developed with the help of 49 patients enrolled in TOPARP-A, a Phase II clinical trial investigating the effectiveness of olaparib.

The drugs do not generally work on cancer cells with functioning BRCA genes, because these are primary DNA fix tools that make PARP unnecessary.

Cancer DNA dropped by nearly half in men who were responding to the drug.

These patients survived and average of 17 months compared with 10 months for those whose cancer DNA levels remained high. They found that cancer cells had acquired new genetic changes that cancelled out the original errors in DNA fix - particularly in the genes BRCA2 and PALB2 - that had made the cancer susceptible to olaparib in the first place.

Lynparza, which is already approved for ovarian and recently produced good results in breast cancer, is now in clinical development against prostate tumours.

According to BBC, Cancer Research UK said the test could "greatly improve survival".

While some patients respond to the drugs for years, others either fail to respond at an early stage or develop resistant cancer.

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