What is lung cancer?
According to National cancer Institute (NCI) definition, Cancer is a term for diseases in which abnormal cells divide without control and can invade nearby tissues. It can involve any organs of the body. When cancer arise from lung, it is called lung cancer.
Is global burden of lung cancer increasing?
According to GLOBOCON, 2020 data lung cancer is the 2nd most common cancer comprising of 11.4% of all cancer. It is the most common cause of cancer related death accounting for 18% of all cancer death. In 2020, there were 2.2 million new cases diagnosed worldwide with lung cancer with 1.8 miilon death. According to WHO there are 2.09 millon new cases diagnosed worldwide in 2018 with 1.76 millon death. According to GLOBOCON 2018 data, there were 67800(6%) new cases diagnosed in India in 2018 with 63500 death(8%). Incidence rate of lung cancer both in men and women is higher in developed countries compared to less developed countries- Possibly related to smoking habbits. In the United States (US) and the United Kingdom (UK), lung cancer incidence and mortality rates have been falling since the 1990s- Probably due to decades of awareness programme and anti smoking policies. In contrast, emerging nations – including Brazil, Russia, India, China, and South Africa (BRICS) – continue to have high rates of cigarette smoking in both men and women. They exhibit a lower incidence of cancer but a higher mortality burden compared with developed countries. Reasons for these patterns include unequal access to healthcare leading to delayed diagnosis and treatment, environmental contamination, and sociocultural barriers.
Is lung cancer increasing in female?
Worldwide, rates of female lung cancer are increasing. In Europe it has exceeded breast cancer mortality rates for the first time in 2017. In some regions, particularly Asia, indoor air pollution and occupational exposures play a greater role in female lung cancer along with increase in female smoking habit.
What causes lung cancer?
Cigarette smoking accounts for about 90% cases of lung cancer. The addictive component of tobacco is nicotine. Although it is not carcinogenic, it fosters tobacco dependence and is also associated with progression of existing lung tumors. Tobacco combustion produces at least 60 known carcinogens. The most significant are polycyclic aromatic hydrocarbons (PAH), including benzo-pyrene; nitrates; and tobacco-specific N-nitrosamines (TSNAs).
Other smoking producet- Canabis Sativa or Marjuana.
Industrial exposure to Nickel, Chromium and some arsenic compound.
Asbestos exposure which can also cause Mesothelioma (Cancer of lining of lung).
Residential radon gas from soil.
Air pollution
Infections- Tuberculosis, HIV
Genetic factors- changes in chromosome regions 5p15, 15q25-26 and 6q21.
Types of lung cancer
Lung cancer is broadly of two type- Nonsmall cell lung cancer and small cell lung cancer.
Symptoms of lung cancer
Persistant or increasing cough
Breadthlessness
Haemoptysis
Unresolving pneumonia
Swelling of neck or arm vein, facial swelling
Different pain syndrome- Aching central chest pain, Chest wall pain, Back pain, Shoulder pain, Facial pain
Systemic symptoms – Weight-loss, anorexia, Fatigue
Swelling of fingers, toes or joints
Low blood sodium ( particularly in small cell lung cancer)
Lung cancer screening:
Screening means checking for cancer (or for abnormal cells that may become cancer) in people who have no symptoms is called screening. Screening can help doctors find and treat several types of cancer early, before they cause symptoms. When cancer is found early, it may be easier to treat. Low dose CT scan has been shown to reduce mortality in high risk patients in clinical trials (NELSON study) but further research is ongoing to define the role of CT scan in lung cancer screening.
Investigation
Initial investigation in a suspected case of lung cancer include Chest X-ray and CT scan. To confirm the diagnosis of cancer either CT guided or Ultrasound biopsy or Bronchoscope guided biopsy is done. Sometimes diagnosis can be confirmed by testing the pleural fluid for cancer cells. Endo bronchial ultrasound (EBUS) is often used to confirm whether the cancer has spread to the lymph node in chest or not. PET-CT scan is often used to exclude any cancer spread outside chest. To assess patient’s fitness for treatment pulmonary function test is done. In advanced stage cancer molecular tests are done on biopsy sample to guide systemic treatment. This includes EGFR, ALK, ROS1, PD L1.
Staging:
Based on size or extent of tumour(T), spread to lymph nodes (N) and spread to distant organ (M) lung cancer can broadly be divided into four stages.
Stage I- Lung tumour 4≤cm size with no spread to lymph nodes or distant organ.
Stage II- Upto 7cm and/or spread to one of the hilar lymph node but no distant spread
Stage III- >7cm in size and/or spread to mediastinal lymph nodes but no distant spread
Stage IV- Spread to distant organ or lining of lung or lining of heart or cancer cells in pleural or pericardial fluid.
The small cell lung cancer is broadly divided into two types which are Limited stage ( when it is confined to chest) and extensive stage (when it spread elsewhere or there is too extensive chest disease).
Treatment:
Treatment of lung cancer depends on Type of lung cancer, stage of cancer, patient’s age, fitness for treatment and other associated medical problem. The treatment option for non small cell lung cancer include the following-
Stage I- Treatment option for stage I include surgery (Removal of one lobe of lung or entire lung with lymph node sampling), Stereotactic ablative radiotherapy, Hypo fractionated radical radiotherapy.
Stage II- Treatment option for stage II include surgery (Removal of one lobe of lung or entire lung with lymph node resection), Stereotactic ablative radiotherapy, Hypo fractionated radical radiotherapy, Chemo radiotherapy, Chemo radiotherapy plus Immunotherapy.
Stage III- Chemoradiotherapy, Chemoradiotherapy plus Immunotherapy, Hypo fractionated radical radiotherapy, Chemotherapy followed by radiotherapy, Surgery (In very selected cases only)
Stage IV- Chemotherapy, Immunotherapy, Chemo-Immunotherapy, Targeted therapy, Palliative radiotherapy.
Limited stage small cell lung cancer can be cured with treatment, which usually involves combination of chemotherapy and radiotherapy. Extensive stage small cell lung cancer is incurable and treatment option include palliative chemotherapy, palliative chemotherapy+Immunotherapy, palliative radiotherapy.
Outcome:
Stage I and stage II cancer can be cured with available treatment. Stage III cancer can still be cured but chance of cure is less. Stage IV lung cancer is usually incurable, although a limited subgroup of patient called Oligo metastatic disease (Small or limited spread to other organ) can be treated with curative intent.