Integration of Liquid Biopsy into Lung Cancer Diagnostic Pathway.

End of project summary

Main Messages

In the current diagnostic pathway in Wales, patients with suspected lung cancer are referred by their GP or present to emergency departments following CT scans. These patients undergo a biopsy to collect a small sample of tumour tissue, which is tested in NHS laboratories. The results are reviewed by clinicians to confirm diagnosis and plan treatment. In many cases, it can take eight weeks or longer from referral or hospital admission for patients to begin treatment. This delay can be critical for those with advanced stage lung cancer, where early treatment is essential to prevent further cancer growth. This study introduces a new blood test that can detect genetic changes (leading to tumour development) in circulating tumour DNA (ctDNA) found in the bloodstream. The test provides results that can be made available to clinicians much sooner than those from traditional tissue biopsy. Earlier availability of diagnostic information can support faster treatment planning, which may be especially beneficial for patients who require urgent care or are unable to undergo a biopsy. In this study: 

• A total of 113 participants with suspected stage III or IV lung cancer were included in the analysis. Of these, 96 (85%) were confirmed to have non-small cell lung cancer (NSCLC), small cell lung cancer, or radiological lung cancer. 
   
• The ctDNA test showed the same results as the tissue biopsy in 98% of cases where both results were available. 
   
• On average, ctDNA results were available two weeks earlier from the date of sample collection and three weeks earlier from the date of cancer suspicion to the test report, compared with tissue test results. 
   
• Actionable variants were detected in 26 participants. These included 16 variants in both ctDNA and tissue samples, 8 in ctDNA only, and 2 in tissue only. 
   
• In the subgroup of 88 participants with confirmed NSCLC or radiological lung cancer, ctDNA testing increased variant detection by 30% compared with tissue testing: 23 cases (26%) versus 18 cases (20%), identifying additional variants that would have otherwise been missed. 
   
• Of the 23 participants with identified variants, 10 (43%) received treatment based on variants found in both ctDNA and tissue. One participant started treatment based on ctDNA results only. Two participants were treated based on tissue-only results. The remaining 10 participants did not receive treatment due to participant’s choice or being unfit for systemic therapy.

Initial results suggest the ctDNA test is reliable, quicker than tissue testing, and may improve the lung cancer diagnostic pathway by reducing time to treatment, especially for patients with actionable variants or those unable to undergo biopsy. These findings require further validation in a larger study.