lung cancer

Lung cancer (primary lung cancer), or frequently if somewhat incorrectly known as bronchogenic carcinoma, is a broad term referring to the main histological subtypes of primary lung malignancies that are mainly linked with inhaled carcinogens, with cigarette smoke being a key culprit.

This article will broadly discuss all the histological subtypes as a group, focusing on their common aspects and for further details please refer to the specific articles on each subtype described below.

Epidemiology

Lung cancer is a leading type of cancer, equal in prevalence to breast cancer . It is the leading cause of cancer mortality worldwide; accounting for ~20% of all cancer deaths .

Risk factors

The major risk factor is cigarette smoking which is implicated in 90% of cases and increase the risk of lung cancer, which can be divided by histological subtype :

  • squamous cell lung cancer: 11x (men), 15x (women)
  • small cell lung cancer: 10x (men), 25x (women)
  • large cell lung cancer: 7x (men), 8x (women)
  • lung adenocarcinoma: 4x (men and women)

Other risk factors:

Associations

Various paraneoplastic syndromes can arise in the setting of lung cancer:

Clinical presentation

Patients with lung cancer may be asymptomatic in up to 50% of cases. Cough and dyspnea are rather non-specific symptoms that are common amongst those with lung cancer.

Central tumors may result in hemoptysis and peripheral lesions with pleuritic chest pain.

Pneumonia, pleural effusion, wheeze, lymphadenopathy are not uncommon. Other symptoms may be secondary to metastases (bone, contralateral lung, brain, adrenal glands, and liver, in frequency order for NSCLC ) or paraneoplastic syndromes.

Pathology

The term bronchogenic carcinoma is somewhat loosely used to refer to primary malignancies of the lung that are associated with inhaled carcinogens and includes four main histological subtypes. These are broadly divided into non-small cell carcinoma and small cell carcinoma as they differ clinically regarding presentation, treatment, and prognosis:

Other malignant pulmonary neoplasms include lymphoma and sarcoma (rare).

Each subtype has a different radiographic appearance, demographic, and prognosis:

Antibodies and markers

Several antibodies or markers from tissue samples may be useful in the diagnosis and prognostication of disease. These include

Staging

Treatment and prognosis

Treatment and prognosis vary not only with stage but also with cell type. In general, surgery, chemotherapy, and radiotherapy are offered according to the stage, resectability, operability, and functional status.

Non-small cell carcinoma
  • treatment
    • operable disease (stage I to IIIA): surgery
    • unresectable disease: neoadjuvant chemotherapy, radiotherapy
    • advanced disease: palliative combined chemotherapy
  • prognosis (5-year survival rates):
    • local (stage I): 55-67%
    • locally advanced (stages II-IIIA): 23-40%
    • advanced (stages IIIB and IV): 1-3%
Small-cell carcinoma
  • treatment
    • limited disease: chemoradiotherapy
    • extensive disease: palliative combined chemotherapy
  • prognosis: poor
    • limited: 5-year survival rate 15-25%
    • extensive: 2-year survival 20% (with palliative combined chemotherapy and supportive care)

See also