On Your Health

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Catching Cancer Early

One of the first and most pressing questions cancer patients want to know after their initial diagnosis is which stage the cancer is at. The answer to this question can often be the difference between a positive prognosis and an uphill battle full of hurdles.

But what exactly do the cancer stages mean and how can the average person decode them? We’re here to walk you through why cancer staging matters, how cancers are classified by stage and how the staging process works.

Why cancer staging matters

Cancer staging is important for both doctors and patients. Doctors need detailed information on the cancer so they can formulate the proper treatment plan.

Cancer staging includes the following information:

  • Primary tumor location
  • Tumor size
  • Number of tumors
  • Depth of cancer cells
  • If it spread to nearby tissues
  • If it spread to lymph nodes
  • If it metastasizes

Cancer diagnosed at an early stage is typically treated with surgery because the tumor is smaller and hasn’t spread. Conversely, cancer diagnosed at a later stage may require chemotherapy first to shrink the cancer cells before undergoing surgery.

Cancer staging also helps patients have a tangible understanding of their diagnosis. Cancers treated in an earlier stage come with a more positive prognosis and a higher chance of survival, while cancers with a late-stage classification are more challenging to treat and come with a lower chance of survival.

Survival rates, which indicate how many people with a certain type of cancer live for a specific amount of time, can offer patients a perspective on what the next five or 10 years may look like. A cancer with a 90 percent five-year survival rate translates to nine out of every 10 people surviving for five years after a diagnosis.

Cancer staging and survival rates are inversely related, meaning stage I cancer has a higher long-term survival rate compared to stage IV cancer that has a lower long-term survival rate. This stresses the importance of receiving regular screenings to catch cancer at an early stage.

How many stages of cancer are there?

Most cancers have four stages, ranging from I through IV — stage I being the least advanced and stage IV being the most advanced. Some cancers can also be categorized as stage 0. This staging scheme was first introduced by the American Joint Committee on Cancer (AJCC) in 1959.

  • Stage 0: This stage is also known as carcinoma in situ (CIS). In situ means “in its original place,” so carcinoma in situ is considered non-invasive because it hasn’t spread beyond the original location to nearby tissue. By definition, CIS isn’t cancer, but it can become cancer if you delay or don’t seek treatment.
  • Stage I: Cancer cells are small and haven’t spread beyond the initial location
  • Stage II: Cancer cells are growing and they haven’t spread beyond the initial location
  • Stage III: Cancer cells are larger and have spread to nearby tissues or lymph nodes
  • Stage IV: Cancer has spread to distant organs, meaning the cancer has metastasized and spread to other organs. This is called metastatic cancer.

INTEGRIS Mammogram

How is cancer staged?

The process of cancer staging can start with a physical examination. This may occur as part of a routine screening, such as a breast cancer mammogram. Your doctor can feel for any lumps from a tumor or check for visual symptoms of swelling or inflammation.

Some forms of cancer rely on imaging to aid in staging. This includes X-rays, computed tomography (CT) scans, magnetic resonance imaging (MRIs), and positron emission tomography (PET) scans.

The use of X-rays in chest radiographs and mammograms help doctors stage breast cancer and lung cancer. CT scans are a more advanced form of an X-ray — CT scans provide three-dimensional images, while X-ray’s are limited to two-dimensional images.

Like a CT scan, an MRI provides three-dimensional imaging, but it offers better soft tissue contrast than a CT scan.

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) use gamma rays to provide detailed information about blood flow and metabolism. PET scans are useful for pancreatic cancer staging.

Following a biopsy (a procedure to collect tissue samples) or surgery, a pathologist can also provide more detailed information about staging based on the size, location and type of cancer cells.

For more information about cancer staging and cancer diagnosis, visit the INTEGRIS Health cancer care page.