128 Mind the ‘Histology Gap’: understanding discrepancy in treatment rates between squamous cell lung cancer and lung adenocarcinoma

Introduction
Advances in the management of lung adenocarcinoma (ADC) rapidly outpace that of squamous cell lung cancer (SCC). Furthermore, SCC patients are commonly a frailer population. However, the size of the ‘histology gap’ is poorly characterised in contemporary datasets. Addressing discrepancies in treatment rates is critical for tailoring care for patients with squamous cell lung cancer.

Methods
Patients with newly diagnosed lung cancer who were referred to medical oncology between August 2022 and August 2025 at the Queen Elizabeth Hospital Birmingham were identified, and records retrospectively reviewed.

Results
20.7% (62/307) of new lung cancer patients seen by medical oncology were histologically confirmed SCC, 59.9% (184/307) were adenocarcinoma. On assessment, 57.3% patients with SCC were PS 0/1, 19.7% were PS 2, and 23.0% were PS 3/4 (compared with 76.4%, 12.4% and 11.2% for adenocarcinoma, respectively). Across all indications, only 46.7% of patients with SCC received systemic anticancer treatment, dropping to 35.7% for patients referred for palliativeintent treatment. In contrast, 68% of patients with ADC referred for palliative treatment received SACT. The most common reasons for palliative systemic treatment not being given in metastatic SCC were poor patient fitness (66.7%), deterioration before treatment initiation (11.1%) and patient choice (11.1%). In patients with metastatic squamous cell lung cancer not fit enough for treatment, median overall survival was 62 days.

Conclusions
This analysis highlights the ‘histology gap’ in NSCLC. Patients with SCC are less fit at assessment and are less likely to receive systemic treatment. These findings highlight the importance of histology-stratified audit reporting, improved optimisation of SCC patient fitness, and expanded access to effective therapies.