Lung Cancer

Overview: Knowing More About Your Diagnosis Can Be Empowering

Being diagnosed with lung cancer – the second most common cancer for men and women in the United States – is overwhelming. However, dramatic advances in precision medicine and the emergence of multidisciplinary care make it increasingly possible for many people with lung cancer to live longer, better-quality lives. These discoveries are being fueled by ongoing research using information available through patient data registries and in clinical trials (see Interview: Lung Cancer Registry).

The first step toward understanding all the new information you’ll hear is to know the specific type and stage of lung cancer you have. If you’re not sure of your exact diagnosis, ask your oncologist so you can use the information in this guide to start conversations with your health care team. These health care professionals are a valuable resource, from helping you understand your diagnosis to designing a survivorship plan. The more you know, the better prepared you’ll be to take an active role in your cancer care and treatment decisions.

How Lung Cancer Begins

It’s helpful to know the basics about the inner workings of your lungs. They are a pair of large, spongy, expandable organs in your chest cavity that are surrounded by a thin layer of protective tissue (pleura). The right lung is a little larger with three parts (lobes), while the left lung has only two.

The lungs’ main function is to exchange oxygen and carbon dioxide. When you breathe in, your lungs absorb oxygen, which is then delivered to the rest of your body. When you exhale, your lungs rid the body of carbon dioxide. Your diaphragm helps your lungs expand and contract when you breathe.

Lung cancer often begins in the lining of the airways when abnormal cells grow out of control, dividing faster and living longer than normal cells. Over time, these cancerous cells accumulate to form a tissue mass (primary tumor). Left untreated, the primary tumor may invade the pleura and form secondary tumors nearby. The cancer cells can eventually crowd out the normal cells to make breathing increasingly difficult.

Lung cancer cells can also spread through the bloodstream or lymph vessels in the lungs. Lymph vessels carry clear fluid (lymph) to lymph nodes, which are small, bean-shaped glands that help your immune system fight infection. Lung cancer often spreads first to lymph nodes in the lungs, then to lymph nodes in the space between the lungs (mediastinum).

In advanced disease, lung cancer cells may break away to form tumors in the opposite lung and distant sites such as the liver, brain or bones. These are known as metastases. Regardless of location, the metastases are still considered lung cancer and treated as such (see Staging).

Types of Lung Cancer

After evaluating and analyzing the cancer cells in a biopsy specimen or fluid taken from the lung or elsewhere, pathologists define the type of lung cancer, which will guide treatment decisions.

Adenocarcinoma is the most common subtype diagnosed, especially in never smokers. It generally begins in the mucus-producing cells in the more distal airways. Because it tends to grow more slowly than other types of lung cancer, adenocarcinoma is slightly more likely to be found before it has spread.

Squamous cell lung cancer (epidermoid carcinoma) starts in the early versions of squamous cells, the thin, flat cells that line the more central airways in the lungs.

Large cell lung cancer, which can develop anywhere in the lungs, tends to grow and spread quickly. When it includes neuroendocrine features, it may behave like and be treated like small cell lung cancer.

Small cell lung cancer, named for its appearance under a microscope, often starts in the central airways (bronchi) in the center of the chest. An aggressive form of lung cancer, it nearly always spreads to distant parts of the body before it is found.

Adenocarcinoma, squamous cell and large cell are sometimes collectively referred to as non-small cell lung cancer (NSCLC), which accounts for the majority of lung cancer diagnoses. Each type has distinct characteristics and responses to treatment, which makes it important for the doctor to determine the specific type.

Much less common types of lung cancer, which can also begin in other organs, include mesothelioma, typical and atypical carcinoid tumors, sarcoma and others.


Questions to Ask Your Medical Team

  • What type of lung cancer do I have?
  • How will we determine the best treatment for me, and what will the goal be?
  • Where will I receive treatment?
  • Will I still be able to work, travel and continue my regular activities during treatment?
  • What side effects should I expect, and whom should I contact with concerns about them?
  • Should I consider a clinical trial?

Additional Resources




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