Lung cancers develop in cells that line the bronchi and in a part of the lung tissue called the alveoli, which are air sacs where gases exchange. Changes to DNA cause cells to grow more rapidly.

There are two main types of lung cancer: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

Keep reading to find out more about the similarities and differences between these two types.

Approximately 80 to 85 percent of lung cancer cases are NSCLC. There are three types of NSCLC:

  • Adenocarcinoma is a slow-growing lung cancer usually discovered in an outer area of the lung, often before it has a chance to spread. It occurs more often in smokers, but it’s the most common form of lung cancer in nonsmokers as well.
  • Squamous cell carcinoma generally occurs in the center of the lung. It tends to develop in smokers.
  • Large cell carcinoma occurs anywhere in the lung, and it usually grows and spreads at a rapid rate.

Approximately 10 to 15 percent of lung cancer cases are SCLC.

SCLC usually starts near the center of the chest in the bronchi. It’s a fast-growing form of cancer that tends to spread in its early stages. It tends to grow and spread much faster than NSCLC. SCLC is rare in nonsmokers.

Early stage lung cancer doesn’t usually produce obvious symptoms. As the cancer progresses, there may be:

Other symptoms may include:

Cancer may spread from the original tumor to other parts of the body. This is called metastasis. There are three ways this can happen:

  • Cancer can invade nearby tissue.
  • Cancer cells can travel from the primary tumor to nearby lymph nodes. They can then travel through the lymphatic system to reach other parts of the body.
  • Once cancer cells enter the bloodstream, they can travel anywhere in the body (hematogenous spread).

A metastatic tumor that forms somewhere else in the body is the same type of cancer as the original tumor.

Stages describe how far the cancer has progressed and are used to determine treatment. Earlier stage cancers have a better outlook than later stage cancers.

The stages of lung cancer range from 0 to 4, with stage 4 being the most severe. It means that the cancer has spread to other organs or tissues.

Treatment depends on many factors, including stage at diagnosis. If the cancer hasn’t spread, removing a part of the lungs may be a first step.

Surgery, chemotherapy, and radiation may be used alone or in some combination. Other treatment options include laser therapy and photodynamic therapy. Other medications may be used to alleviate individual symptoms and side effects of treatment. Treatment is tailored to individual circumstances and may change accordingly.

The outlook varies according to the cancer type, stage at diagnosis, genetics, treatment response, and an individual’s age and overall health. In general, survival rates are higher for earlier stage (stage 1 and 2) lung cancers. Treatments are improving with time. Five-year survival rates are calculated on people who’ve received treatment at least five years ago. The five-year survival rates shown below may have improved as of current research.

  • The five-year survival rate ranges from 45 to 49 percent for those with stage 1A and 1B NSCLC, respectively.
  • The five-year survival rate ranges from 30 to 31 percent for those with stage 2A and 2B NSCLC, respectively.
  • The five-year survival rate ranges from 5 to 14 percent for those with stage 3A and 3B NSCLC, respectively.
  • The five-year survival rate for stage 4 NSCLC is 1 percent, as cancer that’s spread to other parts of the body is often difficult to treat. However, many treatment options are available for this stage of the disease.

While SCLC is much more aggressive than NSCLC, finding and treating all lung cancers early is the best way to improve one’s outlook.