Lung squamous-cell carcinoma — master index¶
Last curated: 2026-08-31 · status: audited · evidence cutoff: 2026-08-31
The condition in five sentences¶
Lung squamous-cell carcinoma (LUSC) is a smoking-associated NSCLC lineage that often develops through central-airway squamous metaplasia, dysplasia, carcinoma in situ, and invasion, although peripheral tumours also occur. Global modelling estimated 616,769 incident LUSCs in 2022—461,171 in men and 155,598 in women—but did not provide a trustworthy histology-specific death count ([PMID 39914442](https://pubmed.ncbi.nlm.nih.gov/39914442/){target="_blank" rel="noopener"}). Its genome is exceptionally complex and dominated by tumour-suppressor loss, copy-number change, squamous-lineage programs, and oxidative-stress biology; frequent alterations have repeatedly failed to become reliable drug dependencies ([PMID 22960745](https://pubmed.ncbi.nlm.nih.gov/22960745/){target="_blank" rel="noopener"}; [PMID 33125909](https://pubmed.ncbi.nlm.nih.gov/33125909/){target="_blank" rel="noopener"}). The systemic-treatment transformation instead came from immunotherapy: nivolumab improved survival after platinum in CheckMate 017, and pembrolizumab plus carboplatin/taxane established a first-line standard with five-year OS 18.4% versus 9.7% ([PMID 26028407](https://pubmed.ncbi.nlm.nih.gov/26028407/){target="_blank" rel="noopener"}; [PMID 36735893](https://pubmed.ncbi.nlm.nih.gov/36735893/){target="_blank" rel="noopener"}). Histology remains a safety variable because pemetrexed efficacy is histology-dependent, some antiangiogenic strategies carry pulmonary-haemorrhage concerns, and a p40-positive lesion is not automatically a lung primary.
Sibling condition: lung adenocarcinoma is the genotype-matched contrast case. TNM staging, LDCT screening, and much checkpoint evidence are NSCLC-wide; pages below label this shared evidence rather than presenting it as LUSC-only.
Start here: overview. The research frontier is in open questions, quantitative extraction in statistics, and growth history in the curation log.
Canonical wiki pages¶
| Page | Scope | Status |
|---|---|---|
| Overview | Integrated definition, clinical map, evidence boundaries, and treatment arc | curated |
| Epidemiology and smoking | Global burden, tobacco dose–response, cessation, radon, asbestos, geography and equity | curated |
| Central-airway biology and presentation | Airway field injury, precursor sequence, obstruction, cavitation and presentation | curated |
| Histology and diagnosis | Morphology, p40/TTF-1, mimics, small-biopsy classification and tissue stewardship | curated |
| Screening and early detection | NLST/NELSON, eligibility, harms, CT-occult central disease and emerging detection | curated |
| Staging | Ninth-edition TNM, invasive nodal staging, resectability and response restaging | curated |
| Molecular landscape | TCGA, pathway architecture, heterogeneity, redox states and actionability limits | curated |
| Failed and frontier targets | FGFR, PI3K, cell cycle, DDR2, redox biology, ADCs and Lung-MAP lessons | curated |
| Immunotherapy | Direct squamous trials, PD-L1, combinations, resistance and immune toxicity | curated |
| Chemotherapy and histology constraints | Platinum backbones, taxanes, pemetrexed, antiangiogenic risk and later lines | curated |
| Early-stage and perioperative therapy | Surgery, adjuvant chemotherapy, neoadjuvant/perioperative IO and stage III therapy | curated |
| Systemic therapy | Integrated metastatic algorithm, sequencing, special sites and palliative care | curated |
| Biomarkers | PD-L1, molecular profiling, TMB, resistance markers, ctDNA and assay discipline | curated |
| Guidelines | Cross-guideline synthesis, decision points, disagreements and version hazards | curated |
| Clinical-trials landscape | Live registry-verified completed, active and recruiting studies; platform design | curated |
| Patient experience and advocacy | Stigma, diagnostic pathways, symptoms, decisions, caregivers, finances and equity | curated |
| Red flags and safety concerns | Oncologic emergencies, treatment toxicity, misclassification hazards and escalation | curated |
Literature layer¶
| Asset | Purpose | Status |
|---|---|---|
| Bibliography | PubMed-verified source ledger with page mappings | audited |
| TCGA landmark note | Genomic architecture and interpretive limits | audited |
| Lung-MAP landmark note | Platform rationale, feasibility and attrition | audited |
| NLST landmark note | Screening mortality benefit and harm interpretation | audited |
| CheckMate 017 landmark note | Direct second-line squamous immunotherapy evidence | audited |
| KEYNOTE-407 landmark note | First-line chemo-immunotherapy and long-term outcomes | audited |
| CheckMate 816 landmark note | Neoadjuvant chemo-immunotherapy and response markers | audited |
| Guideline registry | Current sources, versions, disagreements and update triggers | audited |
| Statistics ledger | Denominators, effect sizes, CIs, endpoint and scope cautions | audited |
| Patient-voice layer | Methods, sources, organizations and thematic synthesis | audited |
Evidence architecture¶
The build separates four levels that should not be collapsed:
- Direct LUSC evidence: histology-specific trials such as CheckMate 017 and KEYNOTE-407.
- Mixed NSCLC evidence: perioperative, stage III, screening, palliative-care and biomarker studies that include but do not independently establish a LUSC effect.
- Mechanistic evidence: genomic, proteomic, spatial and preclinical findings that generate hypotheses but do not select standard treatment.
- Guidance and registry state: recommendations, authorizations and trial status that can change after the evidence cutoff and must be checked at use.
Highest-value unresolved questions¶
- What distinguishes a frequent alteration from a drug dependency in LUSC?
- Can NFE2L2/KEAP1-defined redox states become an assay-locked treatment selector?
- Which baseline signature identifies durable chemo-immunotherapy benefit?
- What is the best post-chemo-immunotherapy sequence?
- How sensitive is LDCT for central and CT-occult LUSC specifically?
- Who needs postoperative checkpoint therapy after neoadjuvant chemo-immunotherapy?
- Can ctDNA or pathologic response safely direct escalation and de-escalation?
- How should frail and ECOG 2–3 populations be represented and treated?
See OPEN-QUESTIONS.md for tiered, study-shaped questions and the cross-domain “Dots not yet connected” map.
Curation state¶
Full build completed 2026-08-29, the first audit pass completed 2026-08-30, and the remaining eight-page audit completed 2026-08-31. All 17 canonical wiki pages are curated. The eight-page completion pass re-queried 153 unique PMIDs and 23 unique NCT identifiers against their live primary registries, repaired registry-scope and reference-list errors, and re-ran the dated evidence-gap searches. See LOG.md for counts, corrections, and validation details.