Definition

Lung carcinoma, commonly referred to as lung cancer, is a type of cancer that originates in the cells of the lungs. Cancer is characterized by uncontrolled cell growth, and in lung carcinoma, this aberrant growth initiates within the lung tissues. Lung carcinoma can metastasize, spreading to lymph nodes or other organs such as the brain. Conversely, cancers from other parts of the body can also metastasize to the lungs.

Typically, lung carcinoma affects older individuals, with rare occurrences in people under 40 years old. While individuals who have never smoked can develop lung carcinoma, smoking remains the primary cause, contributing to approximately 72% of cases. Smoking exposes the lungs to harmful toxins through continuous inhalation, leading to cellular damage. Lung carcinoma ranks as a leading cause of cancer-related deaths globally.

There are two primary types of lung carcinoma based on the microscopic appearance of cancer cells:

• Small cell lung cancer, predominantly found in heavy smokers, is less prevalent than non-small cell lung cancer.
• Non-small cell lung cancer, an umbrella term encompassing several lung cancer types, including squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.

Causes

The primary cause of lung carcinoma is smoking, affecting both active and passive smokers (individuals exposed to cigarette smoke). Cigarette smoke contains carcinogens that damage lung airway cells upon inhalation. Initial exposure may prompt cellular repair mechanisms, but repeated exposure leads to cumulative damage, fostering abnormal cell growth and cancer development over time.

Apart from smoking, radon exposure ranks as the second leading cause of lung carcinoma, according to the American Lung Association. Radon, a naturally occurring radioactive gas, can infiltrate buildings through foundation cracks. Prolonged exposure to other carcinogenic substances can also elevate lung cancer risk, including asbestos, arsenic, cadmium, chromium, nickel, certain petroleum products, and uranium.

Inherited genetic mutations may predispose individuals to lung carcinoma, particularly in conjunction with smoking or exposure to other carcinogens. Some cases of lung carcinoma occur in nonsmokers or individuals with minimal exposure to harmful substances, resulting in idiopathic causes.

Risk Factor

Several factors that can increase your risk of developing lung carcinoma include:

• Smoking. The risk of lung carcinoma increases with the number of cigarettes you smoke each day and the number of years you have smoked. Quitting at any age can significantly reduce the risk of lung carcinoma.
• Exposure to cigarette smoke. Even if you do not smoke, the risk of lung carcinoma increases if you are frequently exposed to cigarette smoke (passive smokers).
• History of previous radiation therapy. If you have undergone radiation therapy to the chest to treat another type of cancer, you may have an increased risk of developing lung carcinoma.
• Exposure to radon gas. Radon is produced from the natural decay of uranium in soil, rock, and water, which eventually becomes part of the air you breathe. Unsafe levels of radon can accumulate in any building, including homes.
• Exposure to asbestos and other carcinogens. Exposure to asbestos in the workplace and other substances known to cause cancer, such as arsenic, chromium, and nickel, can also increase the risk of developing lung carcinoma, especially if you are also a smoker.
• Family history of lung carcinoma. Individuals with parents, siblings, or children who have a history of lung carcinoma have an increased risk of developing the disease.

Symptoms

Lung carcinomas often do not manifest symptoms until the cancer has progressed, but some individuals with early-stage lung carcinoma may experience symptoms. Common symptoms of lung carcinoma include:

• Persistent or worsening cough
• Coughing up blood or rust-colored sputum
• Chest pain exacerbated by deep breathing, coughing, or laughing
• Hoarseness
• Loss of appetite
• Unexplained weight loss
• Shortness of breath
• Fatigue or weakness
• Recurrent or non-resolving lung infections, such as bronchitis or pneumonia
• Wheezing or whistling sounds

When lung carcinoma metastasizes to other parts of the body, it can cause additional symptoms, such as:

• Bone pain, especially in the back or hips
• Neurological changes like headaches, weakness or numbness in limbs, dizziness, balance issues, or seizures due to brain metastasis
• Jaundice (yellowing of skin and eyes) resulting from liver metastasis
• Enlarged lymph nodes, particularly in the neck or above the collarbone

Diagnosis

Diagnosing lung carcinoma typically involves a comprehensive assessment of medical history, symptoms, and risk factors, followed by various diagnostic tests:

• Imaging tests: X-rays, MRI, CT scans, and PET scans can detect abnormal masses in the lungs, providing detailed insights into their size and location.
• Sputum cytology: Microscopic examination of sputum can reveal the presence of cancer cells.
• Biopsy: Tissue samples are collected to confirm the presence of malignant cancer cells. Biopsy methods include:
• Bronchoscopy: A sedated patient undergoes a procedure where a tube is inserted through the throat into the lungs for examination.
• Mediastinoscopy: The doctor will make an incision at the base of the neck. Then a lighted instrument will be inserted, and surgical tools will be used to take a sample from the lymph node. This examination is usually carried out in hospitals under general anesthesia.
• Fine needle biopsy: An imaging test instrument will be used to guide a needle through the chest wall and into the questionable lung tissue. A needle biopsy can also be performed to evaluate lymph nodes.

A pathologist then analyzes the tissue sample. If the results are positive for cancer, other tests will be performed, such as a bone survey, to identify whether the disease has spread and the stage. During the examination, you will be injected with radioactive substances. The picture will then highlight any abnormal bone regions. MRI, CT, and PET scans can all be utilized to assess staging.

Management

Treatment and therapy for lung carcinoma will depend on various factors, including:

• Type of cancer
• Location and stage of cancer
• Overall health of the patient
• Patient preferences

All treatment options can have their own side effects. You should discuss and consult with your doctor regarding the most suitable options for you, including the pros and cons of each option. Some treatment options include:

• Surgery to remove part or all of the lung.
• Chemotherapy, which is treatment with specific drugs that can kill cancer cells and shrink tumors.
• Radiation therapy, which uses high-energy rays to kill cancer cells.
• Radiofrequency ablation, where a healthcare professional inserts a thin needle and uses electric current to destroy cancer cells.
• Targeted therapy, which targets specific parts of the cancer to prevent its growth.
• Immunotherapy, which helps the body fight cancer cells.
• Palliative therapy, including pain relief, oxygen therapy, and other assistance that may be needed to manage symptoms.

Complications

Lung carcinoma can cause several complications, such as:

• Shortness of breath
• Coughing up blood
• Pain
• Fluid in the chest (pleural effusion)
• Cancer spreading to other parts of the body (metastasis), such as the brain and bones.

Prevention

There is no known sure way to prevent lung carcinoma. However, there are things that will reduce your risk, such as:

• Do not smoke. If you smoke, quit and avoid inhaling smoke from smokers.
• Reduce exposure to chemicals known to cause cancer, such as:
• Arsenic
• Asbestos
• Beryllium
• Cadmium
• Nickel or chromium-containing substances
• Coal products
• Air pollution, such as exhaust from diesel engines
• Radon
• Eat a healthy diet
• Exercise regularly

When to See a Doctor?

Consult your doctor if you experience symptoms of lung carcinoma or if you have risk factors that may affect the onset of lung carcinoma.

Looking for more information about other diseases? Click here!