# Novel Approach to Proficiency Testing Reveals Significant Variations in Biomarker Practice Leading to Critical Differences in Lung Cancer Management

## TL;DR

A new testing method shows big differences in how Canadian labs handle lung cancer biomarker tests, which can affect patient treatment.

## Contribution

A novel end-to-end proficiency testing approach for NSCLC biomarker testing was developed and evaluated.

## Key findings

- Turnaround times for molecular reporting ranged from 5 to 57 days with a median of 22.5 days.
- Only 23% of participating laboratories achieved optimal status in the biomarker EQA challenge.
- The proficiency testing approach revealed significant variability in the quality of NSCLC biomarker testing across Canadian labs.

## Abstract

Timely access to quality biomarker testing in NSCLC is critical to patient outcomes. The Canadian Pathology Quality Assurance provides external quality assurance (EQA) to laboratories in Canada. The Canadian Pathology Quality Assurance has recently developed a novel approach to molecular biomarker EQA testing, assessing accuracy, turnaround time, and interpretation of reports. This study reports the results of the first end-to-end biomarker EQA challenge in NSCLC.

Three challenge specimens were made using NSCLC tissue and paired with clinical vignettes mimicking referred-in cases. Participants were to provide all required molecular testing (immunohistochemistry and gene sequencing) and submit final reports for each case, while being timed. Reports were assessed by molecular pathologists and medical oncologists who recommended a systemic treatment based on vignettes and reports.

A total of 13 Canadian laboratories participated. The turnaround time of molecular reporting ranged from five to 57 (median 22.5) calendar days. Two laboratories (15%) reported their results within 2 weeks. Four laboratories (31%) reported the results of their biomarkers after more than 30 days.

Only three laboratories received optimal status (23%). One laboratory (8%) failed due to a critical genotyping error, three (23%) received a suboptimal status due to inappropriately long turnaround times, and the remaining six (69%) received an adequate status.

This report demonstrates the utility of this proficiency testing style compared with standard laboratory self-reporting. The approach has elucidated substantial differences in the quality of NSCLC biomarker results produced by Canadian laboratories. Ongoing efforts to improve turnaround times and clarity of reporting, including regular external measurement, are tools that can improve patient outcomes in NSCLC.