What Is Squamous Cell Lung Cancer?
Squamous cell lung cancer, also called squamous cell carcinoma (SCC) of the lung, is the second most common type of non-small cell lung cancer (NSCLC). It develops in the flat cells lining the inner surfaces of the airways and typically forms near the central bronchi. It is the lung cancer type most strongly associated with tobacco smoking and has distinct characteristics that shape how it is diagnosed and treated.
Squamous cell lung tumours originate in the central airways, typically in the left or right bronchus. This central location places the tumour close to major airways and blood vessels, affecting both the symptoms patients experience and the surgical approach available.
The tumor occurs when squamous cells lining the bronchial tree are repeatedly damaged, especially by carcinogens contained in cigarette smoke, leading to the development of the tumor after many years of exposure.
Causes and Risk Factors
Tobacco smoking is by far the dominant cause. According to research, approximately 80% of lung cancer cases in men and 90% of cases in women are associated with smoking. Among all NSCLC subtypes, squamous cell carcinoma is the one most strongly connected to smoking history.
Other risk factors include:
- Prolonged secondhand smoke exposure
- Older age risk increases significantly with age
- Family history of lung cancer
- Occupational exposure to minerals, metal dust, or asbestos
- Radon gas exposure
One important distinction from adenocarcinoma: squamous cell lung cancer less commonly carries targetable mutations like EGFR or ALK. Biomarker testing is still recommended, as KRAS mutations and PD-L1 expression levels can guide immunotherapy decisions.
Symptoms of Squamous Cell Lung Cancer
Because squamous cell lung cancer grows near the central airways, it is more likely to cause symptoms that are noticed earlier than peripheral tumours.
Common symptoms include:
- A persistent or worsening cough
- Coughing up blood (haemoptysis) is more common in SCC due to proximity to blood vessels
- Shortness of breath or wheezing
- Chest pain or discomfort
- Recurrent chest infections like bronchitis or pneumonia
- Hoarseness or voice changes
- Unexplained weight loss and fatigue
Obstructive symptoms are particularly characteristic of SCC. A tumour partially blocking an airway can cause wheezing, post-obstructive pneumonia, or collapse of a lung segment, symptoms that may prompt earlier investigation than in peripheral lung cancers.
Survival Rates for Squamous Cell Lung Cancer
Squamous cell lung cancer is staged on the standard NSCLC system, from Stage I (localised) through Stage IV (widely spread).
Approximate five-year survival rates:
- Stage I: 60 to 80% localised, no spread to lymph nodes or distant sites
- Stage II: 30 to 50% regional lymph node involvement
- Stage III: 10 to 35% more extensive local or mediastinal spread
- Stage IV: Below 10% distant metastases present
Treatment Options for Squamous Cell Lung Cancer
Surgery
Surgery is the preferred treatment for early-stage SCC (Stages I and II). Common procedures include lobectomy and sleeve resection, a technique often used in SCC because of its central airway location. Sleeve resection removes the tumour with a segment of the bronchus and then reconnects the airway, preserving more lung function than full lung removal.
Radiation Therapy
Radiation therapy is used when surgery is not appropriate, in combination with chemotherapy for locally advanced disease, or to manage symptoms in advanced stages.
Chemotherapy
Chemotherapy is the cornerstone of treatment for advanced squamous cell lung cancer. Platinum-based regimens, typically cisplatin or carboplatin combined with gemcitabine or Paclitaxel, are standard first-line treatment for NSCLC without targetable mutations.
Immunotherapy
Immunotherapy has transformed outcomes for squamous cell lung cancer at later stages. Pembrolizumab and Nivolumab are PD-1 checkpoint inhibitors approved for SCC. In patients with high PD-L1 expression, immunotherapy alone may be used as first-line treatment; in others, it is combined with chemotherapy.
Biomarker testing, including PD-L1 expression, KRAS, and other markers, should be completed at diagnosis to guide treatment planning even when common targetable mutations are less likely.
Conclusion
Squamous cell lung cancer is a challenging but increasingly treatable type of lung cancer, especially if diagnosed early and managed with a personalized treatment plan that may involve surgery, chemotherapy, radiotherapy, and other treatment options. Recognizing the main risk factors, such as smoking and environmental factors, and early symptoms, is an important factor that influences the outcome. When experiencing persistent respiratory symptoms, seeking timely specialist advice is crucial. Consult with a lung specialist online to discuss appropriate investigations and personalised treatment options.
