Lung cancer is the third most common form of cancer in the UK, accounting for around 13% of all cases.


Lung cancers may be classified according to histological subtypes. The main distinction is between small cell and non-small cell lung cancer. Non small cell lung cancer is the most common variant and accounts for 80% of all lung cancers.

Non small cell lung cancer

These share common features of prognosis and management. They comprise the following tumours:
  • Squamous cell carcinoma (25% cases)
  • Adenocarcinoma (40% cases)
  • Large cell carcinoma (10% cases)

Paraneoplastic features and early disease dissemination are less likely than with small cell lung carcinoma. Adenocarcinoma is the most common lung cancer type encountered in never smokers.

Small cell lung carcinoma

Small cell lung carcinomas are comprised of cells with a neuro endocrine differentiation. The neuroendocrine hormones may be released from these cells with a wide range of paraneoplastic associations. These tumours are strongly associated with smoking and will typically arise in the larger airways. They disseminate early in the course of the disease and although they are usually chemosensitive this seldom results in long lasting remissions.


  • Incidence: 77.00 cases per 100,000 person-years
  • Peak incidence: 70+ years
  • Sex ratio: 1:1
Condition Relative
Lung cancer1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+


  • increases risk of lung ca by a factor of 10

Other factors
  • asbestos - increases risk of lung ca by a factor of 5
  • arsenic
  • radon
  • nickel
  • chromate
  • aromatic hydrocarbon
  • cryptogenic fibrosing alveolitis

Factors that are NOT related
  • coal dust

Smoking and asbestos are synergistic, i.e. a smoker with asbestos exposure has a 10 * 5 = 50 times increased risk

Clinical features


Examination findings
  • a fixed, monophonic wheeze may be noted
  • supraclavicular lymphadenopathy or persistent cervical lymphadenopathy
  • clubbing

Paraneoplastic features:

Small cellSquamous cellAdenocarcinoma
  • ADH
  • ACTH - not typical, hypertension, hyperglycaemia, hypokalaemia, alkalosis and muscle weakness are more common than buffalo hump etc
  • Lambert-Eaton syndrome
  • parathyroid hormone-related protein (PTH-rp) secretion causing hypercalcaemia
  • clubbing
  • hypertrophic pulmonary osteoarthropathy (HPOA)
  • hyperthyroidism due to ectopic TSH
  • gynaecomastia
  • hypertrophic pulmonary osteoarthropathy (HPOA)

  • Referral criteria

    NICE cancer referral guidelines for lung cancer suggest the following:

    Refer people using a suspected cancer pathway referral (for an appointment within 2 weeks) for lung cancer if they:
    • have chest X‑ray findings that suggest lung cancer or
    • are aged 40 and over with unexplained haemoptysis.

    Offer an urgent chest X‑ray (to be performed within 2 weeks) to assess for lung cancer in people aged 40 and over if they have 2 or more of the following unexplained symptoms, or if they have ever smoked and have 1 or more of the following unexplained symptoms:
    • cough
    • fatigue
    • shortness of breath
    • chest pain
    • weight loss
    • appetite loss

    Consider an urgent chest X‑ray (to be performed within 2 weeks) to assess for lung cancer in people aged 40 and over with any of the following:
    • persistent or recurrent chest infection
    • finger clubbing
    • supraclavicular lymphadenopathy or persistent cervical lymphadenopathy
    • chest signs consistent with lung cancer
    • thrombocytosis.


    Chest x-ray
    • this is often the first investigation done in patients with suspected lung cancer
    • in around 10% of patients subsequently diagnosed with lung cancer the chest x-ray was reported as normal

    • is the investigation of choice to investigate suspected lung cancer

    • this allows a biopsy to be taken to obtain a histological diagnosis sometimes aided by endobronchial ultrasound

    PET scanning
    • is typically done in non-small cell lung cancer to establish eligibility for curative treatment
    • uses 18-fluorodeoxygenase which is preferentially taken up by neoplastic tissue
    • has been shown to improve diagnostic sensitivity of both local and distant metastasis spread in non-small cell lung cancer


    Of those diagnosed with lung cancer, approximately 75% will be found to have stage III/IV disease at presentation, which has huge implications on the management options available to these patients.

    Lung cancer is histologically subdivided as follows:
    • Non-small cell carcinoma (NSCLC): accounts for 85% of all lung cancers and can be further subdivided into squamous cell carcinoma, adenocarcinoma, and large cell carcinoma
    • Small cell carcinoma (SCLC): accounts for 15% of all lung cancers. SCLC is typically more aggressive and carries a worse prognosis

    The histological subtype is clinically important as the approach to management differs between NSCLC and SCLC. Treatment is also dependant upon the disease stage and patient fitness.

    General management principles
    • Multi-disciplinary team (MDT): All patients with suspected or confirmed lung cancer should be discussed at an MDT to formulate an effective treatment plan
    • Smoking Cessation: For both subtypes of lung cancer, smoking cessation should be encouraged and supported. Patients should be informed that by stopping smoking they are increasing their chances of successful treatment and survival. To help patients stop smoking offer nicotine replacement therapy and refer to smoking cessation services

    NSCLC Management

    Surgical resection:
    • Lobectomy (with hilar and mediastinal lymph node resection/sampling) is first-line treatment for those with stage I or II cancer who are medically fit for surgery. This surgery is done with curative intent.

    • Is first-line for those with stage I-III disease who are not suitable for surgery.
    • This treatment is given with curative intent.

    • Is offered to those with stage III or IV disease to improve survival and quality of life.
    • First line regimes use a combination of:
      • Third-generation chemotherapy agent: e.g. docetaxel, paclitaxel or gemcitabine
      • Platinum agent: e.g. carboplatin or cisplatin

    Combination therapy:
    • Adjuvant chemotherapy should be offered to patients who have undergone a complete resection
    • Adjuvant radiotherapy is offered to patients who have had a incomplete resection of their tumour
    • All patients with stage I-III disease who are not suitable for surgery should be considered for chemoradiotherapy

    SCLC Management

    Surgery is only considered in very early stage I and II disease due to its limited success. The majority of SCLC patients are treated with chemotherapy in combination with radiotherapy:

    Limited-stage SCLC:
    • Limited-stage disease is defined as SCLC without distant metastasis (T1-4, N0-3, M0).
    • First line treatment involves:
      • 4-6 cycles of Cisplatin-based combination chemotherapy
      • Concurrent or adjunct thoracic radiotherapy is only considered if there has been a good response to chemotherapy

    Extensive-stage SCLC:
    • Extensive-stage disease is defined as SCLC with distant metastasis (T1-4, N0-3, M1).
    • First line treatment involves:
      • Platinum-based combination therapy where the patient is reassessed for a response after each cycle (up to a maximum of 6 cycles)
      • Concurrent or adjunct thoracic radiotherapy can be considered if there has been a good response to chemotherapy at both the primary and metastatic sites.

    Relapse after initial treatment:
    • For all stages of SCLC second-line therapy can be considered in those who have relapsed. This includes:
      • Further chemotherapy (maximum 6 cycles)
      • Palliative radiotherapy to control local symptoms


    • Local disease spread: nerve palsy; superior vena cava obstruction and pericarditis
    • Metastatic spread: Brain, spinal cord, bone, liver and adrenal glands are common sites

    Palliative care

    All patients with NSCLC and SCLC who cannot be offered curative treatment should be referred to palliative care. Therapy can involve:
    • Palliative radiotherapy for symptom control
    • Endobronchial stenting or debulking for bronchial obstruction
    • Pleural drainage or aspiration for pleural effusion
    • Dexamethasone therapy for those with symptomatic brain metastasis
    • Opioid therapy to relieve cough and breathlessness


    • SCLC has a worse prognosis when compared to NSCLC
    • 5-year survival is around 10%