In-House Biomarker Testing Shortens Time to Treatment Decision for mNSCLC

In-house biomarker testing helped to overcome barriers to care optimization among individuals with diagnosed metastatic non–small cell lung cancer (mNSCLC), particularly regarding individualized treatment decision, by shortening the period from diagnosis to that treatment decision, according to retrospective analysis findings recently published in Cancer Medicine.

Investigators compared outcomes between 2 periods for patients (N = 165) treated at Sunnybrook Health Sciences Centre in Toronto, Canada. From March 1, 2017, to May 31, 2019, tissue samples were sent outside the center for testing for EGFR, ALK, and PD-L1, and from July 1, 2019, to March 31, 2021, in-house testing was performed for these same biomarkers after in-house testing was initiated at the center.

Tumor marker for analysis | Image credit: angellodeco - stock.adobe.com

The primary outcome was time to treatment decision (TTD).

“In metastatic mNSCLC, increased time to testing is associated with delayed treatment initiation, lower application of appropriate systemic therapies, and increased mortality,” the study authors wrote. “The use of in-house laboratories is one method that has been demonstrated to shorten testing times; however, its impact on the remainder of the lung cancer diagnostic pathway is poorly understood.”

Data on 6 dates were collected from each patient: pathological diagnosis of NSCLC, pathologist request for biomarker testing, sample receipt/accessioning at the send-out or in-house laboratory, reporting of results by the send-out or in-house laboratory, initial medical oncology consultation, and treatment decision for systemic therapy.

There were 92 patients in the send-out cohort and 73 in the in-house cohort. Their median age was 72 (range, 40-95) years, 52% were female patients, and most patients were Caucasian (send-out cohort, 43.5%; in-house, 34.2%) or Asian (25% and 32.9%, respectively) and former smokers (45.7% and 46.6%). The most common type of NSCLC was adenocarcinoma (86%), followed by squamous cell carcinoma (7%), other/not otherwise specified pathology (6%), and large cell carcinoma (0.6%). Also, an ECOG performance status of 0/1 was most common, in 52.2% of the send-out and 60.3% of the in-house groups.

Twice as many patients in the send-out cohort had testing on cytology specimens, at 42% vs 21%, and molecular testing was most common for tissue biopsy or resection specimens (67%).

EGFR mutations were detected in 34% of each group, while ALK results were positive in more of the send-out vs the in-house cohort: 7% vs 3%. PD-L1 tumor proportion scores (TPS) below 1% were more common in the send-out cohort (35% vs 27%)—although this group had 11 percentage points fewer PD-L1 tests ordered—while TPS from 1% to 49% and 50% and higher were more common among the in-house group (26% and 45% vs 14% and 39%, respectively; P = .013).

Regarding the patients who had test results for their last actionable biomarker available at their initial medical oncology consultation, far more patients with in-house testing had these data available compared with patients who had send-out testing: 88% vs 52% (P < .0001). By time of treatment decision, the rest of the patients with in-house testing had results for their last actionable biomarker vs 86% of the send-out cohort.

“The last actionable biomarker denotes the final biomarker outcome necessary to make an informed treatment decision regarding first-line systemic treatment,” the study authors noted.

TTD saw a 44% improvement with in-house biomarker testing: from a median (IQR) of 18 (15-27) to 10 (6-19) days (P < .0001). When each segment of this timeline was broken down, the following results were seen:

• Sign-out of the diagnostic pathology report to opening of the biomarker case file: 1 day in each cohort
• From biomarker testing request to receipt/accessioning of specimen in lab: 2 days for in-house testing vs 3 days for send-out testing
• From receipt of sample in lab to final biomarker report: 96% of in-house cases had a 10 or fewer day turnaround vs 74% of send-out cases

No patients who had in-house biomarker testing started conventional chemotherapy before they received those results, marking a 100% reduction in missed treatment opportunities, the study authors highlighted.

They concluded that although jurisdictional policies have expanded to cover additional testing of ROS-1, BRAF, ERBB2, KRAS, PIK3CA, FGFR1, MET, NTRK1-3, RET, and PD-L1 expression by immunohistochemistry since the periods of their analysis, “we identified challenges that may also be faced in the current era of NGS [next-generation-sequencing] testing through the use of a small number of centralized laboratories.”

Overall, they believe their findings show in-house biomarker testing is advantageous vs send-out testing, especially with its potential to optimize and streamline the personalized medicine process.

Reference

Grafham GK, Craddock KJ, Huan WY, et al. Referred molecular testing as a barrier to optimal treatment decision making in metastatic non-small cell lung cancer: experience at a tertiary academic institution in Canada. Cancer Med. Published online February 5, 2024. doi:10.1002/cam4.6886