Lung Cancer Overview
Lung cancer is a cancer that originates in the lungs. Lung cancer often goes undetected in the early stages, since symptoms don't usually prese...

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Lung Cancer Overview

According to the American Cancer Society (ACS), it is estimated that 224,210 new cases of lung cancer occurred in 2014. Lung cancer accounts for about 13 percent of all new cancers. Those most at risk are older adults over the age of 50, and people who have a history of cigarette, cigar, or pipe smoking. According to the American Lung Association, 82 percent of those living with lung cancer in 2012 were 60 years of age or older. While tobacco smoke is the leading cause, people who have never smoked can develop lung cancer. This can be due to past lung infections, environmental factors, and genetic makeup.

Lung cancer symptoms do not usually present themselves until the cancer is advanced. This is why lung cancer often goes undetected in the early stages. Lung cancer symptoms include:

  • persistent cough
  • coughing up blood
  • chest pain
  • recurring chest infections
  • voice hoarseness

What Is Lung Cancer?

Cancer occurs when cells in the body undergo a mutation that causes them to grow rapidly and uncontrollably. Lung cancer forms when cancer cells invade and destroy healthy cells in the lung tissues and air passages. It can take several years to develop. It may begin as pre-cancerous changes in the lungs that neither cause symptoms nor show up on an X-ray.

Eventually cancer cells accumulate to form a tumor. As the tumor grows, it impedes the ability of the lungs to function properly. Cancerous cells can break away from the original tumor, travel through the bloodstream, and form tumors in other parts of the body. This process is called metastasis.

Types of Lung Cancer

There are two main types of lung cancer. They are small cell and non-small cell. The names refer to how the cells appear to pathologists under a microscope. Each type and stage of lung cancer warrants unique treatment options.

Small Cell Lung Cancer (SCLC)

According to the National Cancer Institute (NCI), small cell lung cancer accounts for 15 percent of all lung cancers. Small cell lung cancer starts in neuroendocrine cells. These are the air tubes that lead to the lungs (the bronchi) and the cells in lung tissue. It grows very quickly. It produces large tumors that can travel through the blood and spread quickly throughout the body. Small cell lung cancer mainly affects heavy or lifetime smokers.

There are two main types of small cell lung cancer. They are small cell carcinoma (oat cell cancer) and combined cell carcinoma. Oat cell cancer is the most common type of small cell lung cancer. The cells resemble oats when examined under a microscope.

Non-Small Cell Lung Cancer (NSCLC)

According to the National Institutes of Health, non-small cell lung cancer makes up about 85 percent of all lung cancer cases in the United States. The cancer cells are larger, and the cancer is slower growing than small cell lung cancer. NSCLC consists of three subtypes:

  • Squamous cell carcinoma (or epidermoid carcinoma) accounts for 25 to 30 percent of all lung cancer. It begins in the cells that line the air passages. If not treated it may spread to the lymph nodes, bones, adrenal glands, liver, and brain. It’s the most common type of lung cancer in men and is heavily linked to smoking.
  • Adenocarcinoma makes up about 40 percent of all lung cancer. It forms in the mucus-producing (outer) part of the lungs. It develops slowly and is the most common type of lung cancer in women and nonsmokers.
  • Large-cell (undifferentiated) carcinoma includes all non-small cell lung cancer that can’t be classified as squamous or adenocarcinoma (about 10 to 15 percent). It sometimes forms near the surface, in the outer edges of the lungs, and grows rapidly.

Long-Term Outlook

According to the American Lung Association, the lung cancer five-year survival rate is lower than many other leading cancers. Over half of people with lung cancer die within a year of their diagnosis.

These statistics often don’t reveal how many of those are still in treatment at the five-year mark as opposed to those who have reached remission (no sign of cancer). Your personal prognosis will be based on a great many factors. These include:

  • type and stage of cancer
  • age at onset
  • overall health
  • lifestyle
  • the success of your treatments

Your overall emotional health can also impact your prognosis. Build a strong support system for yourself and gather as much information about your condition as you can. 

Written by: the Healthline Editorial Team
Edited by:
Medically Reviewed by: Brenda B. Spriggs, MD, MPH, MBA
Published: Oct 2, 2014
Published By: Healthline Networks, Inc.
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