How is head and neck cancer staged?

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headandneckcancercheck_mcxd2u · Accepted Answer

During the process of diagnosing your cancer, the cancer will be staged. Cancer staging is a way of describing the cancer. Diagnosis and staging tell us several things, including where in the body the cancer is located, the severity of the cancer (for example, by indicating the size of the primary tumor), and how far the cancer may have spread from its original location. Staging helps your medical team determine your prognosis (the predicted outcome of the disease) and identify the best treatment option for your particular cancer.
Cancer may be staged at multiple points during the processes of diagnosis and treatment. Your medical team may use one or more of the following types of staging:
- Clinical Staging - This method of staging uses physical examinations, imaging (x-rays, CT scans, MRI, PET scans, etc.), and biopsies to determine the severity and extent of your cancer.
- Pathologic Staging - This method combines the findings used in clinical staging with findings from surgery (for example, if you have a tumor removed or if your medical team does an exploratory surgery).
- Post-Therapy Staging - This type of staging describes the severity and extent of any remaining cancer following an initial course of treatment, such as chemotherapy or radiation.
- Re-staging – Re-staging occurs if your cancer returns following treatment.
Staging describes four characteristics of the cancer:
- Location of the primary tumor
- Size or extent of the tumor
- Whether or not the cancer has spread to lymph nodes near the tumor (e.g., in your neck)
- Whether or not the cancer has spread to distant parts of the body (e.g., in your lungs)
To be effective and useful, cancer staging relies on a set of standardized criteria that allow all medical professionals to have the same understanding of a particular cancer. The staging system used most often in the U.S. and around the world is the TNM Staging System developed by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC).
This system describes a patient’s cancer according to 3 categories, each with multiple grades:
- T – This category describes the extent of the tumor
  - TX: Primary tumor cannot be evaluated
  - T0: No evidence of primary tumor
  - Tis: Carcinoma in situ (early cancer that has not spread to neighboring tissue)
  - T1-T4: Size and/or extent of the primary tumor
- N – This category describes whether or not nearby lymph nodes are involved
  - NX: Regional lymph nodes cannot be evaluated
  - N0: No regional lymph node involvement (no cancer found in the lymph nodes)
  - N1-N3: Involvement of regional lymph nodes (number and/or extent of spread)
- M – This category indicates whether the cancer has spread to distant parts of the body
  - M0: No distant metastasis (cancer has not spread to other parts of the body)
  - M1: Distant metastasis (cancer has spread to distant parts of the body)
It is important to note that each type of cancer has its own classification system. Within head and neck cancer, the numbers and letters for one type do not mean the same as those for another type. For example, in salivary gland cancer a T1 classification means the tumor is smaller than 2cm and does not involve the soft tissues. In sinus cancers a T1 classification means the tumor is confined to one site with no destruction of bone. To better understand your specific cancer stage, ask your doctor to explain it you in terms you and your family understand.
The T, N, and M classifications are then combined to determine a stage of 0, I, II, III, or IV. While stage 0 and I cancers are the least advanced and often easiest to treat, it is important to note that higher-stage cancers can often be successfully treated as well.
As our understanding of cancer evolves, so does the way oncologists stage cancers. As of January 1, 2018, a new staging methodology was put into place by the American Joint Committee on Cancer (AJCC), and the way head and neck cancers are now staged has changed significantly. The most dramatic changes have been made to staging for mucosal melanoma, oropharyngeal cancer, cancer with an unknown primary, and oral cancer. For example, prior to the changes instituted in 2018, most oropharyngeal cancers were classified as stage IV. Today, many of those would be considered stage I or II. We also now know that oropharyngeal cancers that are HPV positive (also called p16 positive)--that is, they contain DNA from the human papillomavirus (HPV)—have a better prognosis than those that are HPV negative. Under the recent changes to the TNM system, there are different staging criteria for HPV-positive and HPV-negative oropharyngeal cancer.