Lung Cancer - Symptoms, Causes, Stages and Treatment

People who smoke have the greatest risk of lung cancer. It frequently has no evident symptoms until the disease is fairly advanced, and it has a dismal survival rate. Lung cancer treatment primarily consists of surgery and chemotherapy. Radiation therapy and targeted medication therapies are further options.

What is lung cancer?

Lung cancer is caused by aberrant cell growth in the lining of the lungs, which leads to the development of a malignant tumor.

Small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) are the two most common forms of lung cancer. They differ in their appearance under a microscope, how they grow and spread to other regions of the body, and how they are treated. NSCLC accounts for around 85 percent of all lung malignancies.

Lung cancer is always fatal; at five years after diagnosis, the total survival rate is around 17%. The explanation for the low survival rate is that lung cancer spreads (metastasizes) rapidly to other places of the body relatively soon after it starts (i.e. before it is diagnosed).

  • Tobacco usage is significantly linked to the development of lung cancer – roughly 80% of lung cancers are caused by tobacco use. Pipe and cigar smoking can also cause lung cancer, but not to the same extent as cigarette smoking. Tobacco smoke contains about 4,000 different chemical components, many of which are carcinogenic (carcinogens).
  • Passive smoking, or the inhalation of tobacco smoke by nonsmokers who live or work with smokers, is also a known risk factor for lung cancer
  • Although tobacco smoking is connected to the majority of lung cancers, not all smokers develop lung cancer, and lung cancer can occur in people who have never smoked or been exposed to second-hand smoke. These findings show that genetic vulnerability (as demonstrated by a family history of the disease) may play a role in lung cancer development.
  • Air pollution (from vehicles, industry, and power generation) and inhalation of asbestos fibers and other cancer-causing chemicals such as arsenic and chromium are two more causes of lung cancer (usually in the workplace).
  • Symptoms

    Lung cancer symptoms vary, and warning indicators are not always visible. Some people with lung cancer have no symptoms until it is diagnosed during a routine chest x-ray or computed tomography (CT) scan.

    Among those who do exhibit symptoms, the following are possible:

  • Coughing and hoarseness that persists
  • Breathing difficulties, wheezing, and chest pain
  • Sputum with blood streaks
  • Chest pain
  • Bronchitis or pneumonia
  • Weight loss, weakness, and fatigue
  • Diagnosis
  • Examinations of the blood
  • Imaging research (chest x-rays; CT, PET, and bone scans)
  • Bronchoscopy is a procedure that examines the lungs (to look inside the airways and take tissue samples, i.e. biopsies)
  • Sputum and bronchial washings cytological investigations (to detect cancer cells in phlegm and lung fluids).
  • A biopsy was performed (sampling of lung tissue with a special biopsy needle or during surgery to see if it is cancerous).
  • The type of lung cancer will be determined by laboratory examination of cells from biopsy samples, and the stage of cancer will be revealed by imaging studies.
  • Lung cancer staging

    The stage of lung cancer relates to how far cancer has gone throughout the body. Staging aids in determining how to treat cancer. Although lung cancer can spread to any organ, the liver, brain, and bones are the most commonly affected. Lung cancer is staged differently in the two types.

    Non-small-cell lung cancer (NSCLC)
  • Stage I cancer is limited to the lungs.
  • Stage II cancer is limited to the chest.
  • Stage III cancer is restricted to the chest, although the tumors are larger and more aggressive than in stage II.
  • Stage VI: cancer that has spread to other parts of the body.
  • Small-cell lung cancer
  • Cancer is in its early stages and is only found in the chest.
  • Cancer that has spread to other places of the body is considered to be at the advanced stage.
  • Treatment

    Cancer treatment consists of surgery to remove cancer cells and chemotherapy and radiation therapy to kill cancer cells. Lung cancer is incurable unless the tumor cells are completely removed surgically.


    Surgery is the most effective treatment for lung cancer, although it is only available for tumors that have not gone beyond the lungs, such as stage I, II, and III NSCLC, as well as in some individuals with restricted stage NSCLC.

    Radiation treatment

    Radiation therapy, which employs high-powered radiation beams to kill cancer cells, has the potential to be employed for both NSCLC and SCLC. The goal is to eliminate cancer cells while avoiding causing too much damage to normal cells. Radiation therapy is an excellent alternative for patients who are unable to undergo surgery. It can also be administered after surgery to eliminate any remaining cancer cells.


    Chemotherapy medications are used to kill rapidly developing cancer cells in both NSCLC and SCLC. Chemotherapy medications can be administered alone or in conjunction with surgery or radiation therapy. Chemotherapy is the first-line treatment for SCLC since it has frequently spread throughout the body by the time it is detected.

    Targeted therapy

    Normal cells are considerably less harmed by molecular-targeted therapies than by chemotherapy or radiation therapy. Tyrosine kinase inhibitors are small-molecule medicines that function inside cancer cells to prevent cancer cells from growing and dividing.

    Monoclonal antibodies are immune system proteins created by humans that inhibit cancer growth and spread by interfering with specific molecules involved in tumor growth and progression.

    Some molecular-targeted medication therapies are only effective if a person's cancer cells contain specific genetic alterations. There is laboratory mutation testing available to establish whether a molecular-targeted therapy medicine will work in a certain person.

  • The most effective way to prevent the development of lung cancer is to not start smoking and to quit smoking if you are already a smoker.
  • Reducing exposure to passive smoking is also an effective preventative measure.
  • Although a person's risk of having lung cancer grows with the amount of time and quantity of cigarettes smoked, stopping smoking, even after many years of smoking, can significantly reduce the chances of developing lung cancer.
  • Taking care to protect oneself from harmful chemical exposure at work, such as wearing essential safety equipment such as a face mask, is also an important lung cancer prevention measure.