Analysing tumour DNA in blood samples could help doctors offer ‘targeted’ treatments best suited to a patient’s lung cancer, a new US study has found.
Researchers at the Dana-Farber Cancer Institute in Boston have developed a DNA test – called a liquid biopsy – that can detect faults (mutations) in two key genes found in lung tumours.
The Dana-Farber/Brigham and Women’s Cancer Center is now offering this analysis to all patients with non-small cell lung cancer (NSCLC) at the point of diagnosis or when the cancer comes back after treatment.
Doctors can access results in around three days, compared to around 12 days for more traditional methods. It is also considerably less invasive than traditional tissue biopsies.
The test involves taking a sample of blood and fishing for free-floating DNA released by dying cancer cells and analysing it for faults.
The technique is also regularly used in research to analyse the molecular make-up of different kinds of cancer. And research into similar tests is also underway in the UK.
Professor Jacqui Shaw, a Cancer Research UK expert in liquid biopsies, said: “This is a great demonstration of how analysing tumour DNA in the blood can help decide which treatments to give lung cancer patients.
“And with a turnaround time of three days, the US team shows that repeat blood tests could help doctors quickly determine whether a treatment is working or not.
The accuracy and reliability of the test was examined in 180 patients with NSCLC, including 120 newly diagnosed patients and 60 who had seen their disease return and become resistant to treatment. The findings are published in the journal JAMA Oncology.
The team focused on two key genes, called EGRF and KRAS, which are faulty in around a third of patients with NSCLC. Each patient also underwent a traditional tissue biopsy to compare against the blood analysis.
The US team believes the test could quickly help doctors determine whether a patient is responding to treatment.
“Those whose blood tests showed a disappearance of the mutations within two weeks were more likely to stay on the treatment than patients who didn’t see such a reduction,” said the study’s lead author, Dr Adrian Sacher.
The analysis could also detect when a new fault appeared in the EGFR gene that makes patients’ tumours resistant to certain ‘targeted’ drugs.
According to Cancer Research UK’s Professor Shaw the emergence of this particular fault may be missed in standard tissue samples. And she believes the blood test could therefore “give doctors valuable time to switch to newer drugs that target this fault”.
“Leading centres in the UK are also looking into this technology,” she added
“And while there are challenges ahead in how this might be used in the NHS, we hope that this approach will one day become routine for our patients.”
- Sacher, A., et al. (2016). Prospective Validation of Rapid Plasma Genotyping for the Detection of and Mutations in Advanced Lung Cancer. JAMA Oncology. DOI: 10.1001/jamaoncol.2016.0173