What Is Lung Cancer?

Lung cancer occurs when cancerous cells grow in the lung. The abnormal growth of the cancerous cells usually starts in the alveoli or the lining of the bronchi. The alveoli are tiny sacs in the lungs that help you breathe in oxygen. The bronchi are tubes that carry air to your lungs.

These cells can later spread to the smaller branches of the bronchi (bronchioles) or the alveoli at the end of these branches. As the disease progresses, lung cancer can invade the surrounding body tissue, lymph nodes, and bloodstream.

Early symptoms of lung cancer can be hard to notice. You may have difficulty breathing, a persistent cough, or coughing up blood as the disease progresses. Treatments depend on the type, what stage of cancer you are in, and the size and location of the tumor.

Lung cancer is the third most common cancer in the United States. More than 230,000 people are diagnosed annually. The disease claims more than 130,000 lives every year, accounting for nearly 25% of all cancer deaths.

Smoking is the leading risk factor for lung cancer. Healthcare providers recommend quitting smoking to lower your risk. Continuing to smoke after you develop lung cancer can quickly worsen your condition. Smoking can be a hard habit to break. Other lifestyle changes may help as you work on using less tobacco.

Types of Lung Cancer

Healthcare providers classify lung cancer into non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC). NSCLC usually spreads slower than SCLC.

Non-Small Cell Lung Cancer (NSCLC)

NSCLC is the most common form of lung cancer, making up about 80% to 85% of all cases. There are three primary types of NSCLC: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

Adenocarcinoma is the most common type of lung cancer. Smoking causes almost 90% of all NSCLC cases. Adenocarcinoma is also the most common type of lung cancer among non-smokers.

Small Cell Lung Cancer (SCLC)

SCLC accounts for about 15% of lung cancer diagnoses. Tobacco use almost always causes SCLC.

SCLC can spread to your brain, liver, and bones very quickly. There are two types of SCLC: small-cell carcinoma (oat cell cancer) and combined small-cell lung carcinoma, which is rare.

Lung Cancer Symptoms

Lung cancer can occur without any early warning signs. A healthcare provider may detect cancer accidentally—say, if you have a chest X-ray for another reason—before you develop symptoms.

Symptoms mostly develop after lung cancer progresses into an advanced stage. Most people have chest-related symptoms, such as:

• Chest pain
• Coughing up blood
• Hoarse voice
• Persistent infections (e.g., bronchitis and pneumonia)
• Persistent or worsening cough
• Trouble breathing
• Wheezing

Lung cancer can affect other body parts if the cancerous cells spread. Symptoms may include:

• Bone pain
• Fatigue and weakness
• Headache
• Swollen lymph nodes
• Unexplained weight loss
• Yellowing of the skin and eyes (if the cancer spreads to the liver)

What Causes Lung Cancer?

Signs and Symptoms of Lung Cancer

Why Does Lung Cancer Cause Back Pain?

How Is Lung Cancer Diagnosed?

What Causes Lung Cancer?

Your genes can sometimes increase your risk of lung cancer. Genetic changes, or mutations, may prompt healthy cells to grow and multiply too quickly.

Mutations mostly result from lifestyle and environmental factors. The most significant risk factor is long-term smoking. People who smoke may be up to 30 times more likely to get lung cancer than those who don't use tobacco.

Risk Factors

Smoking is not the only cause of lung cancer. Other risk factors may include:

• Arsenic in drinking water
• Beta-carotene supplements 
• Exposure to radon, radiation, air pollution, and certain chemicals like asbestos
• Family history of lung cancer
• Secondhand smoke
  

How Is Lung Cancer Diagnosed?

A healthcare provider will likely ask about your lifestyle habits if they suspect you may have lung cancer. They may ask about your medical history and perform a physical exam.

A healthcare provider can perform tests to confirm or rule out lung cancer. A healthcare provider will often use more than one type of test before making an official diagnosis.

Some common diagnostic tools include:

• Bone scan: This scan can examine if cancer cells have spread to your bones.
• Bronchoscopy: This exam is a common way to take a biopsy of your lungs and helps a healthcare provider search for tumors or blockages in your airways.
• Imaging tests: Chest X-rays, CT scans, MRIs, or PET scans take detailed pictures of your lungs to see if cancer cells are present.
• Needle or core biopsy: This test uses a needle to take a sample of your lung tissue to check for cancer cells.
• Sputum cytology: A healthcare provider will ask you to cough up a sample of your mucus and test the mucus for cancer cells.
• Thoracentesis: This procedure removes a sample of the fluid around the lungs to determine the cause of fluid build-up in your lungs.

What Causes Shortness of Breath (Dyspnea)?

Mesothelioma

'Big Bang Theory' Star Kate Micucci Reveals Lung Cancer Diagnosis Despite Never Smoking—How Can That Happen?

Stages of Lung Cancer

A healthcare provider will stage the disease if you receive a lung cancer diagnosis. The stages of NSCLC include: 

• Stage 0: This stage is also known as carcinoma in situ (CIS). Stage 0 is the earliest stage of NSCLC. Cancer cells grow in the lining of the alveoli or air passages but have not spread into the lung tissues.
• Stage I: The tumor in your lung is less than 3 centimeters (cm) in diameter. Cancer cells have not spread to the lymph nodes or other body parts.
• Stage II: The tumor may be larger than 3 cm in diameter. Cancer cells may have spread to nearby lymph nodes but not other body parts. 
• Stage III: Cancer cells have spread to the lymph nodes. These cells commonly invade the lymph nodes in the mediastinum, or the area between your lungs.
• Stage IV: The tumor may be any size or diameter. Cancer cells have spread to the tissue that lines your lungs. A healthcare provider may find cancer cells in nearby or distant body parts.

The stages of NSCLC are further broken down (e.g., stage IIA) based on the size of the tumor and whether it's spread to the lymph nodes or other body parts. SCLC, in contrast, is divided into just two stages: limited and extensive. Limited SCLC occurs when the cancer is contained in the chest area. Extensive SCLC spreads beyond the lungs and into areas of the body that radiation therapy cannot treat.

Treatments for Lung Cancer

A healthcare provider will work with you to choose the right treatment. You may also work with an oncologist, or a healthcare provider who treats cancer. The goal of treatment is to get rid of cancer cells and achieve remission.

Your treatment may depend on your type of lung cancer, stage, and overall health. Common lung cancer treatments include:

• Chemotherapy: A healthcare provider may administer chemotherapy orally or intravenously (through a vein in your arm). Chemotherapy drugs search for and kill cancer cells in your body.
• Cryosurgery: This uses technology to freeze and kill cancer cells.
• Immunotherapy: Drugs strengthen and trigger your immune system to attack cancer cells.
• Palliative care: This form of care is an interdisciplinary approach. A team of healthcare providers help you manage physical symptoms, tend to your emotional health, and provide you with resources to improve your quality of life.
• Radiation therapy: This treatment uses high-energy radiation to kill cancer cells and helps shrink or eliminate tumors. There are several types, including stereotactic body radiation therapy. This type can treat early-stage NSCLC and SCLC.
• Surgery: This can help remove lobes, or sections, of the lung if you are in an early stage of lung cancer. Surgery depends on the size and location of the tumor.
• Targeted therapy: Drugs target cancer cells to prevent them from growing and spreading. Targeted therapy is generally used more often for treating SCLC than NSCLC.

How To Prevent Lung Cancer

Who Should Get Screened for Lung Cancer Now?

What Is a Lung Biopsy?

How To Prevent Lung Cancer

Some risk factors for lung cancer, like genetics, are beyond your control. You can still make some lifestyle changes to decrease your risk.

Smoking is the cause of many lung cancers. Quitting smoking—cigarettes, cigars, and pipes—may lower your risk. Smoking is a difficult habit to kick. You can try other lifestyle changes to reduce your risk in the meantime.

These lifestyle changes:

• Avoid radon exposure: Radon is a colorless, odorless gas that forms when uranium in soil breaks down and builds up in your home. Radon commonly forms in basements. You can buy an at-home test kit or hire a professional to test for radon.
• Eat nutritious foods: Maintaining a balanced diet that limits high-fat or highly processed foods can help lower your risk.
• Get annual lung cancer screenings: Annual screenings will not prevent lung cancer. Early screenings can help diagnose the disease before it progresses. Yearly screenings can help you get early treatment and reduce your risk of dying from lung cancer. Talk to a healthcare provider about whether you are eligible for annual screenings. Eligibility may depend on your age and history of smoking.
• Try minimizing exposure to secondhand smoke: Inhaling secondhand smoke, or smoke caused by someone else's cigarettes, is not something you can always control. Some ways to avoid exposure to secondhand smoke are to stay away from indoor public places (e.g., restaurants) that allow smoking. Ask people not to smoke in your car or home.

Related Conditions

Some evidence suggests that respiratory and cardiovascular diseases may be common in people with lung cancer. Respiratory diseases may damage the lungs and cause trouble breathing. Smoking, for example, is a common risk factor for chronic obstructive pulmonary disease (COPD). COPD can block the airways in your lungs. People with COPD are more likely to develop lung cancer than others.

Cardiovascular diseases are also common among people who have lung cancer due to smoking. People with lung cancer may have heart problems, for example, from long-term tobacco use.

Living With Lung Cancer

Incorporating healthy behaviors, such as eating nutrient-rich foods and getting regular exercise, can improve your quality of life as you undergo treatments for lung cancer. Having lung cancer can feel scary, frustrating, and isolating. You might be feeling some common side effects from your treatment, such as fatigue, nausea, vomiting, stress, anxiety, and depression.

Living with lung cancer is not easy. These options may enhance your quality of life:

• Ask your loved ones for help with daily tasks.
• Eating nutritious foods that you enjoy.
• Get good sleep and rest throughout the day.
• Go on walks or do light to moderate exercise.
• Partake in hobbies and activities.
• Spend time with family or friends.
• Stay hydrated.
• Talk to a healthcare provider or reach out to a mental health specialist if you need additional support.
• Try deep breathing, relaxation, or massage techniques to help reduce stress.
  

A Quick Review

Lung cancer begins as an overgrowth of cancer cells that line the airways or another part of the lung. The disease can invade the surrounding body tissue, lymph nodes, and bloodstream as it progresses. Smoking is the leading risk factor for lung cancer. A variety of lifestyle changes, such as reducing tobacco use, can help lower your risk of lung cancer.

There are several treatments for lung cancer, such as chemotherapy, radiation, or palliative care. Living with lung cancer is not easy and can often make you feel anxious or afraid. It's OK to feel this way. Keep in mind that you are not alone in your diagnosis. Resting, staying active with exercise or hobbies, and spending time with your loved ones during this journey can improve your quality of life.

FAQs