To determine overall cascade testing rates and identify factors associated with uptake among family members after the identification of a pathogenic or likely pathogenic variant (P/LPV) in a proband.
Approach:
Study Design: Retrospective, cross-sectional study conducted through a single diagnostic testing laboratory, assessing demographics, cancer history, genetic test results, and family member testing.
Population: Probands who underwent mutigene panel testing between December 2016 and August 2020 and were found to have a P/LPV in Lynch syndrome or hereditary breast and ovarian cancer genes.
Data Collection: Clinical information derived from test requisition forms, clinical documents, and ICD-10 codes. Cascade testing defined as at least one family member undergoing genetic testing after the proband's positive result.
Variables Assessed: Demographic (sex, age, race/ethnicity), clinical (cancer history, genes impacted), and economic factors (availability of free testing, SES based on zip code).
Key Findings:
Cascade testing is performed only for a minority of probands.
Demographic factors such as race, ethnicity, and socioeconomic status are associated with lower rates of genetic testing.
The impact of free testing policies on cascade testing rates has not been well studied.
Interpretation:
The study identifies disparities in cascade testing uptake among different demographic and socioeconomic groups.
Limitations:
Limited studies exist on cascade testing uptake following identification of P/LPVs.
The study was conducted at a single diagnostic laboratory, which may limit generalizability.
Conclusion:
The study aims to determine cascade testing rates and identify factors influencing uptake.
