What Is Lung Cancer

Lung cancer takes more lives than breast, prostate and colon cancers combined. It also accounts for 27% of all cancer deaths and roughly over 228,000 new cases of lung cancer every year. While breast cancer awareness continues to increase, lung cancer awareness is just as important.

So what is lung cancer? Lung cancer is a cancer that forms in tissues of the lung, usually in the cells lining air passages. The two main types are small cell lung cancer and non-small cell lung cancer. These types of cancers are diagnosed based on how the cells look under a microscope.

Lung cancer is the uncontrolled growth of abnormal cells, usually those that line the air passages, which start off in one or both lungs. Instead of developing into healthy lung tissue, these abnormal cells divide rapidly and form tumors. As these tumors grow larger and become more numerous, they decrease the lung’s ability to provide the bloodstream with oxygen.

Tumors that remain in one place and do not appear to spread are known as benign tumors. Whereas tumors that spread to other parts of the body, either via the bloodstream or lymphatic system are referred to as malignant tumors.

Primary lung cancer originates in the lungs, while secondary lung cancer starts somewhere else in the body and spreads or metastasizes to the lungs.  Each type is considered a different type of cancer and is not treated the same way.

What Causes Lung Cancer?

Carcinogens – Anything that increases your chance of getting a disease is called a risk factor.  Carcinogens are a class of substances that may promote cancer.  Tobacco, asbestos, arsenic, car exhaust fumes or radiation such as x-rays or even sun are examples of carcinogens.  Roughly 87% of lung cancers are related to smoking and inhaling the carcinogens in tobacco smoke, which also includes secondary smoke inhalation.

Genetics – A person’s genes may make them more predisposed to getting lung cancer.

Certain risk factors may contribute to lung cancer. Having a risk factor, however, does not mean that you will get cancer, and not having any risk factors doesn’t mean that you will not get cancer either.

  • Smoking – the leading cause of lung cancer. – includes cigars and pipes

  • Radon Exposure

  • Radiation (being treated with radiation therapy to the breast or chest)

  • Asbestos (workplace, etc.)

  • Air Pollution

  • Arsenic

  • Some Organic Chemicals

  • Genetic Predisposition – having a family history of lung cancer.

  • Secondhand Smoke

  • 20,000 to 30,000 people who have never smoked are diagnosed with lung cancer in the US each year.


Lung cancer symptoms will vary, depending on the location of the cancer, whether it has spread and the size of the tumor. In its earliest stages, lung cancer typically does not cause symptoms. Many of these symptoms may
take years before they appear, often appearing after the disease is in an advanced stage

  • Persistent or intense coughing.

  • Ache or pain in the chest, back or shoulder from coughing.

  • Changes in the color of the mucus that is coughed up.

  • Difficulty breathing or swallowing.

  • Hoarseness of the voice or wheezing.

  • Coughing up blood

  • Recurring respiratory infections (bronchitis or pneumonia.

  • Enduring cough that is new or different

Additional symptoms can appear if the lung cancer spreads or metastasizes. Swollen or enlarged lymph nodes are common and likely to present early.  If cancer spreads to the brain, patients may experience vertigo, headaches, or even seizures.

Screening – How is Lung Cancer Diagnosed?

Physicians use information revealed by symptoms as well as from other procedures to help diagnose for lung cancer. Some of the imaging techniques used to screen for lung cancer include X-rays, Bronchoscopy (a thin tube with a camera on the one end), CT scans, MRI scans or PET scans.

While these diagnostic techniques help to provide important information, the only absolute way to diagnose lung cancer is by taking a biopsy where the cancer cells are examined with a microscope.

Lung Cancer Staging

Once a cancer diagnosis is confirmed, an oncologist will determine the stage of the cancer and how far the cancer has spread. The stage of the lung cancer determines which choices are available for the treatment.

How is lung cancer classified?

Lung cancer may be classified into two distinct types based on the appearance of the cancer under a microscope. These types are non-small cell lung cancer (NSCLC) and small cell lung cancer.

Small Cell Lung Cancer – This form of lung cancer usually starts in the bronchi, which are the two main airways that branch off the windpipe.  Though the cancer cells for this type of cancer are small, they grow very rapidly and create large tumors. These tumors usually spread quickly to other parts of the body, including the liver, brain and bone.  Generally, most small cell lung cancers spread outside the lung areas before they are detected.  This type of lung cancer occurs almost exclusively to heavy smokers.

Non-Small Cell Lung Cancer (NSCLC) –  Non-small cell lung cancer accounts for 80% of lung cancers, while small cell cancer accounts for the other 20%.  NSCLC can be further divided into four different types; each type provides different cancer treatment options.

  • Squamous Cell Carcinoma – This is the most common type of lung cancer in men. Cancer that begins in the squamous cells, within the lining of the bronchial tubes.Squamous Cell Carcinoma
  • Large Cell Carcinoma – This is a rapidly growing lung cancer which originates near the outer edges or surface of the lungs.
  • Adenocarcinoma – This is the most common type of lung cancer amongst women and non-smokers. This cancer forms in the mucus producing glands of the lungs.
  • Bronchiolveolar Carcinoma – This is a rare form of Adenocarcinoma which forms near the lungs’ air sacs.

Smoking (pipes and cigars included) increases the risk of non-small cell lung cancer. The earlier in life a person starts smoking, the more often a person smokes and the more years they smoke, the greater the risk of lung cancer. If a person stops smoking, the risk becomes lower as the years pass.

How is Lung Cancer Treated?

Treating lung cancer depends on the type of cancer, its stage and how far it has spread, as well as the age and health status of the patient, including any personal characteristics. Patients generally receive a combination of treatments, which may include surgery, chemotherapy and/or radiation.

New cancer research continuously looks for new, more effective ways to treat lung cancer. There have also been recent developments in the fields of hormone therapy, immunotherapy (this therapy stimulates a patient’s immune system to work harder or more efficiently to attack cancer cells) and gene therapy. Targeted cancer treatments, like the cancer drug Afatinib, focus only on treating the patient’s cancer cells while leaving healthy lung cells alone, also show promise.

Patients should discuss their options with their health care team. Lung cancer treatment is always changing. Please ask your doctor about new and promising treatments, or getting involved in a clinical trial.

Oncology Associates also participates in several clinical trials, including non-small cell lung cancer  – learn more about these studies.