Lung cancer is a massive topic, but for the UKMLA AKT, it’s all about knowing the "red flags," the diagnostic pathway, and the key differences between the types. It’s one of those high-yield areas where the NICE guidelines are very specific.

Let's break this down into the essentials you'll need for the exam.

1. Types of Lung Cancer

We generally split them into two main buckets: Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC).

• Non-Small Cell Lung Cancer (NSCLC) ~85%:
  • Adenocarcinoma: The most common type overall. It’s often found peripherally and is the most common type in non-smokers.
  • Squamous Cell Carcinoma: Usually central (near the bronchi). It’s strongly associated with smoking and can cause hypercalcaemia (due to PTHrP production).
  • Large Cell Carcinoma: Fast-growing and can occur anywhere in the lung.
• Small Cell Lung Cancer (SCLC) ~15%:
  • Very aggressive and usually central.
  • It’s a neuroendocrine tumor, so it loves to cause paraneoplastic syndromes like SIADH (low sodium) or Cushing’s (high ACTH).
  • Usually has already metastasized by the time it's found.

2. Investigation Pathway (NICE Guidelines)

The "2-week wait" (2WW) pathway is a classic exam favorite.

1. Chest X-ray (CXR): Usually the first-line investigation. Look for hila enlargement, peripheral nodules, or pleural effusions.
2. Urgent CT Chest/Abdomen (with contrast): If the CXR is suspicious or if the patient has high-risk symptoms (like persistent hemoptysis in a smoker), this is the next step to stage the disease.
3. Biopsy for Histopathology: To confirm the type. This can be done via:
   • Bronchoscopy/EBUS (Endobronchial Ultrasound): For central tumors.
   • CT-guided biopsy: For peripheral tumors.
4. PET-CT: Used to see if the cancer has spread elsewhere before deciding on surgery.

3. Staging and Treatment

Staging uses the TNM system (Tumour, Node, Metastasis).

• NSCLC Treatment:
  • Early stage: Surgery (Lobectomy is the gold standard) is the goal for a cure.
  • Advanced stage: Radiotherapy, chemotherapy, or targeted biological therapies (like EGFR inhibitors).
• SCLC Treatment:
  • Since it’s usually widespread at diagnosis, surgery is rarely an option.
  • It's very responsive to Chemotherapy and Radiotherapy, but unfortunately, it often recurs.

I've got a great table that compares these types side-by-side to help you keep the paraneoplastic syndromes straight.