What is Lung Cancer?

Lung cancer is a disease where abnormal cells grow uncontrollably in the lungs, forming tumors that can interfere with breathing and spread to other parts of the body.

Lung cancer begins in the cells of the lungs, most commonly in the lining of the air passages. It occurs when these cells mutate and begin to divide uncontrollably, forming a mass or tumor. You may not notice symptoms in the early stages, but as the cancer grows, it can cause coughing, chest pain, shortness of breath, and weight loss.

What are the Types of Lung Cancer?

Lung cancer is primarily classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), based on how the cells look under a microscope and how they behave in your body.

1. Non-Small Cell Lung Cancer (NSCLC) – ~85% of Cases

NSCLC is the most common type. It usually grows and spreads more slowly than SCLC. NSCLC has three main subtypes:

Adenocarcinoma: This is the most common subtype, especially among non-smokers. It starts in the outer parts of the lungs and often spreads before showing symptoms. It accounts for around 40% of all lung cancers.

Squamous Cell Carcinoma: Found more often in smokers, this type develops in the central parts of the lungs near the main airway (bronchus). It makes up about 25–30% of lung cancer cases.

Large Cell Carcinoma: A less common and aggressive subtype that can appear in any part of the lung. It tends to grow and spread quickly, making it harder to treat. It represents roughly 10–15% of NSCLC cases.

2. Small Cell Lung Cancer (SCLC) – ~10–15% of Cases

SCLC grows rapidly and is more likely to spread early. It usually begins in the central airways and is strongly linked to cigarette smoking. Because of its aggressive nature, treatment often involves chemotherapy and radiation rather than surgery.

SCLC is further divided into:

Limited stage: Cancer is confined to one lung and nearby lymph nodes.

Extensive stage: Cancer has spread to the other lung or distant organs.

What are the Symptoms of Lung Cancer?

The most common symptoms of lung cancer include a persistent cough, chest pain, shortness of breath, coughing up blood, fatigue, and unexplained weight loss.

Detailed Explanation of Each Symptom:

Persistent Cough

You may notice a cough that doesn’t go away or worsens over time. This is often one of the earliest signs, especially if you’re a smoker. A chronic cough lasting more than 2–3 weeks should be evaluated.

Coughing Up Blood (Hemoptysis)

Even a small amount of blood in your mucus when you cough can be a warning sign. This happens when the tumor irritates or damages the airway lining.

Chest Pain

You might feel dull, aching, or sharp chest pain, especially when breathing deeply, coughing, or laughing. The pain may result from the tumor pressing against the chest wall or ribs.

Shortness of Breath

This can occur when the tumor blocks airways or when fluid builds up in the lungs (a condition called pleural effusion). You may find yourself winded doing activities you used to handle easily.

Hoarseness

If the cancer affects the nerve that controls your voice box (recurrent laryngeal nerve), your voice may sound hoarse or weak.

Unexplained Weight Loss

Losing 10 pounds (about 4.5 kg) or more without trying could be a sign. Lung cancer can affect your body’s metabolism and appetite.

Fatigue

Extreme tiredness not relieved by rest is common. Cancer cells can use up your body’s energy or trigger inflammatory responses that leave you drained.

Recurring Infections

You may experience repeated episodes of pneumonia or bronchitis, especially in the same area of the lung. This happens if the tumor blocks airflow and traps bacteria.

Swelling in the Face or Neck

A tumor in the upper lung may press on a major vein (superior vena cava), causing swelling in your face, neck, or arms. This is known as superior vena cava syndrome and may also cause headaches or dizziness.

What are the Causes of the Lung Cancer?

Lung cancer is mainly caused by smoking, but other proven causes include long-term exposure to radon gas, asbestos, air pollution, certain chemicals, and inherited genetic mutations even in people who have never smoked.

Detailed Explanation of Lung Cancer Causes:

Cigarette Smoking

This is the leading cause, linked to about 80%–90% of lung cancer deaths. When you smoke, your lungs absorb toxic substances like benzene, arsenic, and formaldehyde around 70 of which are confirmed carcinogens. The longer you smoke and the more cigarettes you use daily, the higher your risk. Even if you quit, the risk stays elevated for years but gradually decreases over time.

Secondhand Smoke

If you live or work around smokers, you’re also at risk. According to the U.S. CDC, secondhand smoke exposure causes over 7,000 lung cancer deaths each year among non-smokers in the U.S. alone.

Radon Gas

Radon is a naturally occurring radioactive gas that can seep into homes and buildings from the soil. It’s the second leading cause of lung cancer in the U.S. and the leading cause among non-smokers, responsible for roughly 21,000 deaths per year. You can’t see or smell radon, so testing your home is the only way to detect it.

Asbestos Exposure

If you’ve worked in construction, shipbuilding, or industries that used asbestos, you may have inhaled fibers that stay lodged in your lungs. Long-term exposure significantly increases your risk of mesothelioma, a rare type of lung-related cancer, and also raises the risk of regular lung cancer especially when combined with smoking.

Air Pollution

Long-term exposure to polluted air especially fine particulate matter (PM2.5) can raise your lung cancer risk, even at relatively low concentrations. According to the WHO, air pollution causes approximately 1 in 10 lung cancer deaths worldwide.

Occupational Hazards

Certain chemicals like arsenic, diesel exhaust, nickel, and chromium compounds are linked to lung cancer. If you’re exposed to these substances in the workplace without proper protection, your risk may rise over time.

Genetic Predisposition

If someone in your family has had lung cancer, you might carry inherited gene mutations that make you more vulnerable. These genetic changes may affect how your body repairs damaged DNA or processes toxins, even if you’ve never smoked or been exposed to other risk factors.

What are the Preventions of Lung Cancer?

The best ways to prevent lung cancer include avoiding tobacco, testing your home for radon, reducing exposure to toxic substances, maintaining a healthy lifestyle, and getting regular screenings if you’re at high risk.

Accurate and Descriptive Explanation of Lung Cancer Prevention:

Don’t Smoke or Quit Smoking

Avoiding tobacco is the most effective way to prevent lung cancer. If you smoke, quitting at any age significantly lowers your risk. According to the American Cancer Society, after 10 years of quitting, your risk of dying from lung cancer drops by about 50% compared to a current smoker. If you need help quitting, talk to your doctor about nicotine replacement therapy, counseling, or medications like varenicline.

Avoid Secondhand Smoke

Breathing in smoke from others puts you at risk. If you live or work with smokers, encourage smoke-free environments. Secondhand smoke is known to cause thousands of lung cancer deaths in non-smokers each year.

Test Your Home for Radon

Radon is a natural radioactive gas that can enter your home through cracks in floors and walls. It’s the second leading cause of lung cancer, especially among non-smokers. You can buy a radon test kit or hire a professional. If your home has high levels, radon mitigation systems can lower it.

Wear Protective Gear in the Workplace

If your job involves exposure to carcinogens like asbestos, diesel exhaust, or industrial chemicals (e.g., arsenic, chromium), use proper ventilation and personal protective equipment. Long-term exposure without safety measures can elevate your risk significantly, especially when combined with smoking.

Limit Air Pollution Exposure

While you can’t eliminate pollution completely, you can reduce your exposure. Avoid outdoor activities on days with poor air quality, and use air purifiers indoors. According to the WHO, outdoor air pollution is linked to 15% of lung cancer deaths worldwide.

Eat a Healthy Diet

Although diet alone won’t prevent lung cancer, eating plenty of fruits and vegetables may support your lung health. These foods contain antioxidants and nutrients that help protect your cells from damage.

Stay Physically Active

Regular exercise improves lung function and boosts your immune system. Aim for at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous activity per week, as recommended by the CDC.

Get Screened if You’re at High Risk

If you’re between 50 and 80 years old, have a 20 pack-year smoking history, and currently smoke or quit within the past 15 years, the U.S. Preventive Services Task Force recommends annual low-dose CT scans. Screening can detect lung cancer early, when it’s more treatable.