Successful trial of genetic test to guide personalised cancer therapy

A new genetic test that will help to tailor drugs to cancer patients' individual tumours has been successfully trialled in the US.

The SNaPshot test rapidly identifies mutations in 14 known cancer genes in a sub-set of lung cancer tumours, and is the first to feasibly incorporate genetic screening into standard care.

Similar tests could soon be used for a range of cancers to enable wide-spread administration of gene-targeted drug treatments. It is hoped this will increase patient responsiveness and survival rates.

According to Dr Lecia Sequist, who led the study at Massachusetts General Hospital, genetic screening is likely to become 'part of everyday care' for cancer patients. 'Smart drugs' that are designed specifically to kill cancer cells with a mutation not present in normal cells are already available, added Dr Dora Dias-Santagata, who was also involved in the study. The aim is to 'match individual patients with the therapies that will most likely be effective', she said.

The study, published in the Annals of Oncology, genetically screened 546 patients with non-small-cell lung cancer (NSCLC) and identified mutations in 51 percent of samples using the SNaPshot technique. The two most common mutations were in the genes KRAS and EGFR. Of the 353 patients diagnosed with advanced NSCLC, 22 percent were either given, or enrolled onto a clinical trial for, a gene-targeted drug as a direct result of their genetic screen.

'Choosing the right therapy can raise response rates in NSCLC patients from around 20-30 percent to 60-75 percent and may improve survival', said Dr Sequist.

An additional number of patients were also guided away from specific treatments. For example, patients with EGFR mutations respond well to drugs called tyrosine kinase inhibitors, while KRAS mutations are associated with resistance to these drugs.

The key to widespread use of genetic screening in cancer treatment is producing a quick and cost effective test. SNaPshot's success is due to its ability to screen NSCLC tumours for over 50 mutations in a one go and provide results within, on average, a few weeks. Previously only a small number of mutations could be tested for at once. According to the Guardian, the test is now being offered to specialist lung cancer hospitals and clinics in the US at a cost of around £310 per test.

Cancer Research UK are launching a two-year genetic screening pilot later this month, which will run until July 2013. It aims to recruit up to 9,000 patients with a range of cancers including breast, bowel, lung and prostate, ovary and melanoma.

James Peach, Cancer Research UK's programme director, told the Guardian: 'It's great to see the successful delivery of a cancer gene panel test in normal clinical practice. The next step is to build on these studies to develop a national network that can deliver high-quality, universally accessible and cost-effective gene panel testing'.