Lung Cancer

Definition/diagnostic criteria

Lung cancer is characterised by uncontrolled cell growth in tissues of the lung, often leading to metastasis. Diagnostic criteria hinge on histological examination following imaging and biopsy. The condition is categorised primarily into non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), with NSCLC accounting for approximately 85% of cases. Diagnosis is confirmed via biopsy and imaging studies, including chest radiography, CT scans, and PET scans, supported by bronchoscopy or needle biopsy for tissue sampling.

Epidemiology

Lung cancer is the third most common cancer and the leading cause of cancer death in the UK, with around 47,000 new cases and 35,000 deaths annually. Smoking is the primary risk factor, implicated in over 85% of cases. Other risk factors include exposure to radon gas, occupational hazards, air pollution, and familial predisposition. The incidence is higher in men than in women and increases significantly with age.

Diagnosis

Clinical features

Symptoms of lung cancer are often nonspecific and can include a persistent cough, haemoptysis, dyspnoea, chest pain, and systemic symptoms such as weight loss and fatigue. Signs may also encompass finger clubbing, lymphadenopathy, and features indicative of metastasis or paraneoplastic syndromes.

Investigations

Initial assessment typically involves chest radiography. Anomalies or suspicion of cancer prompt further examination through CT scans of the chest and upper abdomen to assess the extent of disease and guide biopsy. PET scans may be utilized for staging. Bronchoscopy or CT-guided biopsy enables histological diagnosis. Blood tests, including a full blood count, liver and renal function tests, and calcium levels, support the diagnosis and assess general health.

Treatment

Treatment depends on the stage and type of lung cancer, overall health, and preferences of the patient. NSCLC may be treated with surgery, radiotherapy, chemotherapy, targeted drug therapy, or a combination of these. Early-stage SCLC may be treated with chemotherapy and radiotherapy, while advanced SCLC often requires systemic chemotherapy as the mainstay of treatment.

Supportive care, including pain management, palliative care, and smoking cessation advice, is integral to management.

Prognosis

Prognosis varies widely based on the stage at diagnosis, with a five-year survival rate for all stages combined at around 15%. Early-stage lung cancer has a significantly better prognosis, highlighting the importance of early detection and intervention. Factors adversely affecting prognosis include advanced stage, poor performance status, weight loss, and SCLC histology.