Lung Cancer Stages

The Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 8, 2013


My Father-in-law was recently diagnosed with Stage IV Lung cancer. Could you tell me what that means?


Mitchell Machtay, MD, Radiation Oncologist, responds:

The "stage" of a cancer indicates how advanced someone's cancer is. Early stage means that the cancer is relatively small and well confined, while very advanced stage cancer generally means that it has spread throughout the body. Cancer experts have developed "staging systems" for most of the major types of cancer. These classification systems can be very complex and are perhaps overemphasized, but they provide physicians with a form of "medical shorthand" to describe the anatomy and extent of a patient's cancer. Stage is one factor that can be used to estimate prognosis, and it often determines treatment.

In lung cancer, the staging system consists of 4 major categories or stage groupings (Stages I through IV) The 4 major Stage categories of lung cancer are as follows:

  • Stage I: The lung cancer (the primary tumor) is confined to one portion of one lung, with no evidence of spread to nearby lymph nodes (small glands within or nearby the lung) nor anywhere else in the body.
  • Stage II: Spread to nearby (hilar) lymph nodes has occurred, but the lung cancer (primary tumor) itself is still "relatively" limited and has not spread anywhere else in the body.
  • Stage III: The primary tumor has grown outside of the lung into adjacent organs in the chest (such as the heart, major arteries, windpipe, or esophagus), or it has spread to "mediastinal" and/or supraclavicular lymph nodes – small glands that are located in between the two lungs and in the lowest part of the neck. There is still no distant spread throughout the body.
  • Stage IV: Spread of the cancer to distant parts of the body, such as the opposite lung, the brain, the bones and/or the liver.

Prognosis is best for Stage I. Stage II is also considered to be relatively early lung cancer. Unfortunately, most lung cancer patients are not diagnosed until the cancer has already reached Stage III or IV. The dramatic difference in prognosis between Stage I and stages III/IV has influenced some physicians to screen people who are thought to be at high risk for lung cancer. The hope is that by using screening tests (such as low-dose chest CT scans), lung cancers can be detected at the earliest possible stage when cure is most likely. In some patients, the stage of their cancer is immediately obvious, just based on a 10-minute physical examination. However, in many situations, it is very difficult to determine the correct staging, and this could require complex scans and/or exploratory surgery. For example, many lung cancers that were thought to be stage I based on CT scans and other tests turn out to have stage II or even III disease after surgery is completed. "Under staging" and "over staging" are common problems in oncology and reflect the limitations of current technology.

Proper staging is an important part of caring for a patient with lung cancer. However, stage should absolutely not be the only factor used to determine a treatment plan and to assess prognosis. Many patients with Stage IV disease are excellent candidates for aggressive therapies that can improve both survival time and quality of life. Conversely, some patients with Stage I disease have a very short life expectancy regardless of treatment, often due to conditions other than their lung cancer. Extremely important factors in addition to stage to consider include:

  1. The cancer histology (the appearance of the tumor under the microscope).
  2. The patient's general health and strength.
  3. The patient's nutritional status, particularly extent of weight loss.
  4. The exact anatomic location(s) of the cancerous tumor(s).

Above all, the most important factor in deciding on a treatment plan should be the patient and his or her family's goals and desires. As said by Abraham Lincoln, "In the end, it's not the years in your life that count. It's the life in your years."