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genoCDS is a clinical reference tool for qualified healthcare professionals only. Content is derived from published guidelines and regulatory sources and may contain errors or outdated information. It is not a substitute for professional medical judgment, institutional protocols, or individual patient assessment. Always verify recommendations against current primary sources before making clinical decisions. Full disclaimer →
Stage Stage IVA
Single extrathoracic metastatic lesion or contralateral lung nodule or pleural/pericardial involvement. Metastatic but potentially oligometastatic.
4 test recommendations across 1 clinical indication
Stage IVA squamous NSCLC. NCCN recommends broad molecular profiling for all metastatic squamous NSCLC (updated recommendations). PD-L1 required. Targetable mutations less common than adenocarcinoma but present in ~15–20% of cases.
Required — 2 tests
Comprehensive Solid Tumor NGS Panel
Comprehensive NGS
Next-generation sequencing panel covering ≥300 cancer-relevant genes, including all major NSCLC drivers (EGFR, ALK, ROS1, BRAF, KRAS, MET, RET, NTRK, HER2, FGFR), plus tumor mutational burden (TMB) and microsatellite instability (MSI). Examples include FoundationOne CDx, Tempus xT, Caris MI Transcriptome, and equivalent institutional panels. Preferred over single-gene sequential testing for efficiency and cost-effectiveness.
Ordering Note
Comprehensive molecular profiling required for metastatic squamous NSCLC (NCCN). While driver mutation frequency is lower than adenocarcinoma, ~15–20% of squamous tumors harbor actionable alterations.
Specimen
Evidence
NCCN Category 1 for metastatic squamous NSCLC — comprehensive molecular profiling now recommended for all histologies.
ASCO/CAP/AMP/IASLC: molecular testing recommended for squamous NSCLC at advanced stage.
PD-L1 Expression by Immunohistochemistry (IHC)
PD-L1 IHC
Measurement of PD-L1 (programmed death-ligand 1; CD274) protein expression on tumor cells by IHC. Reported as Tumor Proportion Score (TPS) for NSCLC. Key thresholds: TPS <1% (PD-L1 negative), TPS 1–49% (low expression), TPS ≥50% (high expression). FDA-approved companion diagnostics: 22C3 pharmDx (pembrolizumab), 28-8 pharmDx (nivolumab), SP142 (atezolizumab), SP263 (durvalumab). PD-L1 ≥50% qualifies for pembrolizumab monotherapy first-line; all TPS levels are relevant for combination chemo-immunotherapy selection.
Ordering Note
PD-L1 required. PD-L1 ≥50% in squamous NSCLC: pembrolizumab monotherapy has strong data. Chemo-immunotherapy (pembro + carboplatin + paclitaxel/nab-paclitaxel; KEYNOTE-407) effective across all PD-L1 levels.
Specimen
Evidence
Recommended — 2 tests
Tumor Mutational Burden (TMB)
TMB
Quantitative measurement of the number of somatic mutations per megabase (mut/Mb) of tumor genome. High TMB (TMB-H, ≥10 mut/Mb per FoundationOne CDx) is an FDA-approved pan-tumor biomarker for pembrolizumab (Keytruda). In NSCLC, TMB-H correlates with improved response to immune checkpoint inhibitors independently of PD-L1 expression. TMB is typically calculated from comprehensive NGS panels (FoundationOne CDx FDA-approved for TMB). Note: TMB thresholds and clinical utility vary by assay platform — direct comparison between assays requires caution.
Specimen
Evidence
Microsatellite Instability / Mismatch Repair Status (MSI/MMR)
MSI/MMR
Testing for microsatellite instability (MSI) and/or mismatch repair (MMR) deficiency. Methods: PCR-based MSI testing, IHC for MMR proteins (MLH1, MSH2, MSH6, PMS2), or NGS-based MSI calculation. MSI-H (high instability) / dMMR (deficient MMR) is an FDA-approved pan-tumor biomarker for pembrolizumab and dostarlimab. MSI-H/dMMR is rare in NSCLC (<1%) but justifies routine testing given pan-tumor approval. IHC for MMR proteins can be performed on most tissue specimens.
Specimen
Payer Coverage
Payer Coverage Summary
Coverage status as of last policy review. Prior authorization requirements and coverage criteria may change. Verify directly with each payer before ordering.
| Test | Medicare (CMS) | UnitedHealth | Anthem BCBS | Humana | Cigna | Aetna |
|---|---|---|---|---|---|---|
| Comprehensive NGS | Covered | Covered | Covered | Prior Auth | Covered | Covered |
| PD-L1 IHC | Covered | Covered | Covered | Covered | Covered | Covered |
| TMB | Covered | Prior Auth | Covered | Prior Auth | Covered | Covered |
| MSI/MMR | Covered | Unknown | Unknown | Unknown | Unknown | Unknown |
Coverage data last verified via automated policy research. Always confirm current policies with each payer.
Recommendations on this page are derived from publicly available guidelines (NCCN, ASCO, ESMO, FDA, OncoKB) and are paraphrased for reference. They do not constitute medical advice. Evidence levels reflect the grading systems of each respective organization and should be interpreted in clinical context. This reference is updated periodically but may not reflect the most recent guideline revisions.