Oral cancer stages

Designing an individualized treatment plan for oral cancer begins with knowing the stage, or progression, of the disease. The stage of oral cancer is one of the most important factors in evaluating oral cancer treatment options.

The care team uses a variety of diagnostic tests to evaluate oral cancer and develop an individualized treatment plan. After a patient receives a diagnosis, the care team will review his or her pathology to confirm the diagnosis and staging information before developing a treatment plan. If the patient has a cancer recurrence, the care team will perform comprehensive testing and recommend a treatment approach that is personalized to the patient's cancer type and stage.

How is oral cancer staged?

The care team stages oral cancer using the American Joint Committee on Cancer’s TNM system, a commonly accepted method based on three key components, listed below.

T (tumor): This describes the size of the original tumor.

N (node): This indicates whether the cancer is in the lymph nodes.

M (metastasis): This refers to whether the cancer has spread to other parts of the body.

A number (0-4) or the letter X is assigned to each factor. A higher number indicates increasing severity. For instance, a T1 score indicates a smaller tumor than a T2 score. The letter X means the information could not be assessed.

Once the T, N and M scores have been established, an overall stage is assigned.

T categories for oral cavity cancer

These measurements refer to the primary oral cancer tumor.

TX: Primary tumor cannot be assessed; information not known.

TO: No evidence of a primary tumor has been found.

Tis: Carcinoma in situ has been diagnosed, meaning the disease is still localized, or contained within the top layers of cells lining the oral cavity. Cancer cells have not invaded the deeper layers of oral tissue.

T1: Tumor is 2 cm across or smaller.

T2: Tumor is larger than 2 cm across, but smaller than 4 cm.

T3: Tumor is larger than 4 cm across.

T4 is divided into two subgroups, detailed below.

• T4a: The tumor is growing into nearby structures. At this stage, the oral cancer is called a moderately advanced local disease. The areas to which cells have spread vary according to the type of oral cancer. 
  • For oral cavity cancers, the tumor is growing into nearby structures, such as the bones of the jaw or face, deep muscle of the tongue, skin of the face, or maxillary sinus.
  • For lip cancers, the tumor is growing into nearby bone, the inferior alveolar nerve (the nerve to the jawbone), the floor of the mouth, or the skin of the chin or nose.
• T4b: The tumor has grown through nearby structures and into deeper areas or tissues. At this stage, the cancer is called very advanced local disease, and may include any of the following conditions:
  • The tumor is growing into other bones, such as the pterygoid plates (in the skull) and/or the skull base. This type of spreading may occur with any oral cancer.
  • The tumor surrounds the internal carotid artery. This type of spreading may occur with any oral cancer.
  • For lip and oral cavity cancers: the tumor is growing into an area called the masticator space.

N categories for oral cavity cancers

NX: Nearby lymph nodes cannot be assessed; information not known.

N0: The oral cancer has not spread to nearby lymph nodes.

N1: The cancer has spread to one lymph node on the same side of the head or neck as the primary tumor. This lymph node is smaller than 3 cm across.

N2: This category is divided into these subgroups:

• N2a: The oral cancer has spread to one lymph node on the same side as the primary tumor, and the lymph node measures 3-6 cm across.
• N2b: The cancer has spread to two or more lymph nodes on the same side as the primary tumor. No lymph nodes are larger than 6 cm across.
• N2c: The oral cancer has spread to one or more lymph nodes on both sides of the neck or on the side opposite the primary tumor. No lymph nodes are larger than 6 cm across.
• N3: The cancer has spread to a lymph node that measures more than 6 cm across.

M categories for oral cavity cancers

M0: No distant spread has been detected.

M1: The oral cancer has spread to distant sites outside the head and neck region (for example, the lungs, liver or bones).

Stages of oral cancer

Stage 0 oral cancer

The cancer is only growing in the epithelium, the outermost layer of tissue in the oral cavity or oropharynx. No cancer cells are present in deeper layers of tissue, nearby structures, lymph nodes or distant sites (carcinoma in situ).

Stage 1 oral cancer

The primary tumor is 2 cm across or smaller, and no cancer cells are present in nearby structures, lymph nodes or distant sites.

Stage 2 oral cancer

The oral tumor measures 2 cm to 4 cm across, and no cancer cells are present in nearby structures, lymph nodes or distant sites.

Stage 3 oral cancer

A stage 3 oral tumor describes one of the following:

The oral tumor is larger than 4 cm across, and no cancer cells are present in nearby structures, lymph nodes or distant sites.

The oral tumor is any size but hasn't grown into nearby structures or distant sites. However, cancer cells are present in one lymph node, which is located on the same side of the head or neck as the primary tumor and is smaller than 3 cm across.

Stage 4 oral cancer

There are three categories in this stage, as detailed below.

• In stage 4A oral cancer, one of the following applies:
  • T4a, with or without lymph node involvement: The oral cancer tumor is growing into nearby structures and may be any size. Cancer cells may not be present in the lymph nodes, or they may have spread to one lymph node, which is located on the same side of the head or neck as the primary tumor and is smaller than 3 cm across. Cancer has not spread to distant sites.
  • N2, with any size tumor: The tumor is any size and may or may not have invaded nearby structures, it has not spread to distant sites, and one of the following is true:
    • Cancer cells are present in one lymph node, are located on the same side of the head or neck as the primary tumor, and measure 3-6 cm across (N2a).
    • Cancer cells are present in one lymph node on the opposite side of the head or neck, and measure less than 6 cm across (N2b).
    • Cancer cells are present in two or more lymph nodes, are smaller than 6 cm across, and are located on either side of the head or neck (N2c).

• In stage 4B oral cancer, one of the following applies:

• Stage 4C oral cancer, with any T, and any N, M1: There is metastasis with a tumor of any size or lymph node involvement. Cancer cells have spread to distant sites, most often the lungs.

Oral cancer survival rate

Identifying the stage of cancer not only helps the care team determine a treatment plan, it also helps predict a potential prognosis. This is achieved by calculating the percentage of people with oral cancer who survive at least five years after diagnosis compared to people who don’t have that type of cancer. It’s important to remember that this is only a statistic based on all people with oral cancer several years in the past, so individual patient experiences may vary. 

The National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) Program bases the survival rate for oral cancer on where the cancer started and how far the cancer has spread, as indicated below.

Localized: The cancer hasn’t spread beyond the tissue in which it developed. The five-year relative survival rate for localized oral cavity and pharynx cancer is about 87 percent.

Regional: The cancer has spread to nearby tissues or lymph nodes. The five-year relative survival rate for regional oral cavity and pharynx cancer is about 69 percent.

Distant: The cancer has spread to farther reaches of the body. The five-year relative survival rate for distant oral cavity and pharynx cancer is about 39 percent.

The overall five-year relative survival rate for oral cavity and pharynx cancer is 68.5 percent, according to the SEER program.

Keep in mind that the survival rate for oral cancer depends on a variety of factors, including the patient’s age, overall health and the extent of the disease, so always talk to the care team about the patient’s individual prognosis.

Next topic: How is oral cancer diagnosed?