Lung Cancer: Causes, Stages, Symptoms, and Treatment

The abnormal growth of cells causes lung cancer. This is because the cells grow into a mass or tumor. An abnormal growth in the body that invades nearby tissues and organs, spreads to other areas, or can return after removal is called “malignant” or cancerous.

Who is at Risk for Lung Cancer?

Lung cancer may take years to develop, but early detection and treatment greatly improve the chances of a successful outcome. Cigarette smoking is one of the most common risk factors for developing lung cancer. Exposure to cigarette smoke or its harmful components can cause permanent changes in the lungs for many people. These changes can lead to the development of a cancerous tumor within the lung. About 25% of all lung cancer cases occur in people who have never smoked. The underlying cause is not understood in these cases. Two out of three people diagnosed with lung cancer are over 65.

Stages of Lung Cancer

Staging allows the doctor to fully understand the extent of the patient’s cancer to make treatment decisions and predict expected outcomes.

The TNM System

The TNM system is a way to classify diseases by their symptoms.

• T – Your lung cancer stage is based on how big the tumor is and where it is located in your lungs or body.
• N – indicates the number of times a node is involved in a certain path. This test helps determine if your cancer has reached the lymph nodes near your lungs.
• M – stands for metastasis. This indicates whether your cancer has spread or not.

Lung cancer may metastasize to the other lung, liver, bones, brain, kidneys, adrenal glands, or various other organs in the body.

Your doctor can identify your tumor’s stage by listing the letters and numbers 0-4. Your tumor will be measured in centimeters and assigned a number; the larger the number, the more it has grown or spread. They could also use X as a number. This means the tumor cannot be measured, or it is unclear how far it has spread. When your doctor says your lung cancer is “unresectable,” surgeons can’t remove it.

Small-Cell Lung Cancer Stage

If you have this type of cancer, your doctor may use the TNM system to classify it. They will assign your cancer a stage according to its severity.

If you have this type of cancer, your doctor may use the TNM system to classify your cancer. They will then place your cancer in one of two main stages:

• Limited stage: The disease remains in a single lung and may affect nearby lymph nodes, but it hasn’t advanced to the other lung or outside the lung area.
• Extensive Stage: Your tumor has spread to other parts of your lungs and chest. It might have reached the fluid surrounding your lungs (pleura) or spread to other organs.

Non-Small-Cell Lung Cancer

Non-small-cell lung cancer is more common than small-cell lung cancer. Its clinical stage can classify NSCLC. Doctors may use image scans to take pictures of the body to confirm the clinical stage of cancer. A small piece of tissue may be taken from the tumor and biopsied to confirm the diagnosis.

If you undergo cancer surgery, your doctor can examine the tumor to determine the pathological stage of the disease. This report tells your doctor how far the cancer has spread or grown.

NSCLC is most often staged using the TNM system, where each letter is followed by a number ranging from X to 4.

Number and letter combinations include

• The width of your tumor, measured in centimeters, or if it’s too small even to measure
• Where your tumor is in your lungs
• When there is more than one tumor in the same lung
• If your airways are partially blocked or so congested that a collapsed lung or pneumonia may occur
• Whether the tumor has reached your lymph nodes or spread to other organs

Doctors may use general stages to classify NSCLC. For example, your doctor may use the TNM system and numbers to determine the stage of cancer in each of the following cases:

• Occult Stage: Cancer cells can be found in the mucus you cough up. No tumor can be seen by image scan or biopsy. It’s also known as hidden cancer.
• Stage 0: The tumour is microscopic. The cancer cells haven’t spread to other parts of your body or to other people.
• Stage 1: The cancer is located in your lung tissue but is not present in your lymph nodes.
• Stage 2: The disease may spread to the lymph nodes near your lungs.
• Stage 3: There is a possibility that the disease has spread to your lymph nodes near your lungs.
• Stage 4: Cancer has spread throughout your body. It could have spread to your brain, bones, or liver.

Causes

Lung cancer occurs when lung cells undergo abnormal changes, leading to uncontrolled growth. Key causes include:

• Smoking and Tobacco Use: The primary cause of tobacco smoke is carcinogens that damage lung cells and trigger cancer.
• Radon Gas Exposure: Inhaling this radioactive gas from soil and rocks can increase lung cancer risk.
• Air Pollution and Toxins: Long-term exposure to polluted air, asbestos, or industrial chemicals can lead to lung cancer.
• Genetic Mutations: Inherited genetic changes can raise the risk, even in non-smokers.
• Chronic Lung Inflammation: Conditions like COPD or tuberculosis can cause lung tissue damage, increasing cancer risk.
• Unknown Causes: Some cases occur without clear risk factors, possibly due to spontaneous genetic mutations.

Symptoms

Lung cancer usually has no symptoms in its early stages. However, if the cancer is symptomatic, it may cause shortness of breath, coughing, or chest pain. When signs of illness begin to appear, they may include:

• Chronic hacking, raspy cough, sometimes with bloody phlegm
• Changes in a cough that you have had for a long time
• Frequent respiratory infections, like repeated episodes of bronchitis or pneumonia
• Shortness of breath that gets worse
• Wheezing
• Persistent chest pain
• Hoarseness
• Swelling of the neck and face
• Pain and weakness in your shoulder, arm, or hand
• Fatigue, Weakness, weight loss, and appetite, fever that comes and goes
• Severe headache and body aches
• Difficulties swallowing

Risk Factors for Lung Cancer

Various factors, such as lifestyle habits, environmental conditions, and genetic susceptibility, can raise the risk of lung cancer.

Smoking

Cigarette smoking is the most crucial risk factor for developing lung cancer. The use of other tobacco products, such as cigars or pipes, also increases the risk of lung cancer. Tobacco smoke is a mixture of more than 7000 different chemicals. Many things can be poisonous. Smoking cigarettes is a leading cause of lung cancer and death. People who do not smoke are 15 to 30 times more likely to avoid this fate. Even smoking a few cigarettes a day occasionally increases the risk of lung cancer.

Smoking cigarettes is a leading cause of lung cancer and death. People who do not smoke are 15 to 30 times more likely to avoid this fate. Even smoking a few cigarettes a day occasionally increases the risk of lung cancer. A person’s risk of smoking-related diseases increases with both the number of years they smoke and the daily number of cigarettes they consume.

Second-hand Smoke

Secondhand smoke from other people’s cigarettes, pipes, or cigars can cause lung cancer. When a person inhales indirect smoking, it seems that they are smoking.

Family history of lung cancer

A person’s family history may increase lung cancer risk; this risk increases with exposure to other risks, such as smoking. You are twice as likely to have cancer if a family member has lung cancer as if there is no history of the disease in your family.

Diagnosis

A doctor usually diagnoses lung cancer by examining the patient’s symptoms and medical history. A biopsy may also determine the cancer’s stage and how far it has spread. Your doctor may suspect lung cancer if the physical exam shows:

• Swollen lymph nodes above the collarbone
• Abdominal mass
• Weak breathing
• Abnormal lung sounds
• Sluggishness when patted on the chest
• Unequal students
• Sagging eyelids
• Weakness in one arm
• Dilated veins in the arms, chest, or neck
• Swollen face

If lung cancer is causing symptoms, it is usually visible on an X-ray. On a chest X-ray taken for another cause, lung cancer that has not yet shown signs may occasionally be visible.

Your doctor might advise a chest CT scan if they feel that a more detailed exam is necessary. For example, a lung cancer diagnosis is usually confirmed with a lung biopsy. A thin, illuminated tube is passed through your nose or mouth and directed into the airways to access the tumor. They then remove a tiny tissue sample. This is a bronchoscopy with a biopsy performed using endobronchial ultrasound (EBUS) guidance. This is useful for tumors near the center of the lung.

Treatment

Lung cancer treatment options vary based on the cancer type and the extent of its spread. For example, certain individuals with non-small cell lung cancer may receive surgery, chemotherapy, radiation therapy, targeted therapy, or a mix of these treatments.

• Surgery is a medical procedure that is used to treat a variety of illnesses and injuries. A process in which doctors cut out cancerous tissue.
• Chemotherapy is a type of cancer treatment. Cancer can be treated with certain medicines that will shrink or kill it. Medications can be pills you take, medications in your veins, or sometimes both.
• Targeted therapy approaches treat a disease or condition that focuses on specific body areas. For example, cancer cells can grow and spread if not stopped. Drugs can help block the growth and spread of cancer cells. These drugs may be taken in pill form or intravenously as an anesthetic. You will first be given tests to see if targeted therapy suits your cancer type. If it is, this treatment will be used.

Frequently Asked Questions