Whilst liquid biopsies have emerged as a non-invasive and cost-effective alternative to tissue biopsies and are increasingly used in clinical practice, there is still uncertainty on how findings should be interpreted by treating oncologists. Here, we used liquid biopsies to characterise patients with advanced cancer and provide clinical interpretation and recommendations via the Genomic Tumour Advisory Board (GTAB) of the NHS South East Genomic Laboratory Hub.
Twenty seven patients with metastatic or unresectable disease were offered circulating tumour DNA (ctDNA) assay testing between November 2021 to January 2022 at St George’s University Hospital in London, UK. Written consent was obtained for all patients. ctDNA was isolated from peripheral blood using the FoundationOne® Liquid CDx assay that reports genomic alterations in 324 genes, microsatellite instability and blood tumour mutational burden. Assays were provided by Roche through a Familiarisation Programme. Results were reviewed by the GTAB to identify patients potentially eligible for NHS-approved clinical trials based on a genomic biomarker as well as those requiring referral to Cancer Genetics.
Median age of patients was 54 years (29-85) and 63% were males. Tumour type varied and included cancers of the colorectum (40%), lung (15%), breast (15%), kidney (15%), penis (7%) and ovary (4%). Approximately 85% of the patients were previously treated with 33% having received more than two lines of treatment. ctDNA was not isolated in two patients (7%) likely due to low tumour burden. There was 100% concordance between standard molecular tissue testing and ctDNA results. Thirteen patients (48%) were eligible for at least one clinical trial based on a genomic biomarker. Three patients (11%) were referred to Cancer Genetics due to a potential germline mutation or young age and family history.
We found that 48% of heavily pre-treated cancer patients were eligible for a clinical trial based on a genomic biomarker. Our results support the benefits of molecular profiling for allocating patients to clinical trials, and importantly, highlight the need to support oncologists with clinical interpretation and recommendations of findings through a GTAB for subsequent patient management.
The authors.
Roche.
All authors have declared no conflicts of interest.