Are There Socio-Demographic Inequalities in the Utilisation of Tumour and ctDNA Somatic Mutation Testing in Solid...

Somatic mutation testing in solid tumours represents a rapidly advancing field which increases opportunities for access to molecularly targeted therapeutics and clinical trials. This systematic review determined whether socio-demographic inequalities affect utilisation of novel somatic mutation testing.

Following PRISMA 2020 guidance, MEDLINE, EMBASE, Scopus, CINAHL, Web of Science, PubMed and PsycINFO were searched for peer-reviewed studies (January 2018-March 2025). Data was extracted reporting utilisation of novel somatic mutation testing panels, including Oncotype DX, for solid tumours by socio-demographic measures. A modified International Society for Pharmacoeconomics and Outcomes Research (ISPOR) checklist assessed study quality. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated where needed and narrative synthesis undertaken. Data was stratified by receipt of Oncotype DX testing and next-generation sequencing (NGS) panels.

The 27,749 citations screened identified 24 studies meeting the inclusion criteria. These reported on two modalities of testing (Oncotype DX and other NGS sequencing panels) across five cancers. Twenty-three studies were from US populations. These highlighted disparities in utility of testing across socio-demographic measures and particularly decreased utilisation with increased age, non-white ethnicity, lower socio-economic status, and non-private insurance. The mean study quality score by a modified ISPOR checklist was 8.3/10.

These results provide a contemporary update on evidence of disparities in access to novel genomic testing. As an expanding field, this requires further investigation to prevent accentuations in inequitable implementation of precision oncology and differences in outcomes between different socio-demographic groups.