What Are the Stages of Oropharyngeal Cancer?

Written by Sonya Collins
Medically Reviewed by Laura J. Martin, MD on June 23, 2025
10 min read

Oropharyngeal cancer is the most common type of throat cancer. After your diagnosis, you will learn the stage of the cancer. The stage lets you know how far, if at all, the cancer has spread from the place that it started. Doctors use the stage to help choose the best treatment for you and to let you know what to expect. 

Oropharyngeal cancer staging, like staging for most cancers, is based on the size of the tumor, how far it has spread from the original site, whether lymph nodes are involved, and whether it’s reached other organs farther away from the original site.

There’s more than one way to stage throat cancer. Panels of experts from different organizations create their own guidelines for staging, which may vary slightly from one to the next. Most doctors and cancer centers use the American Joint Committee on Cancer (AJCC) TNM system to stage throat cancer, but they may also refer to other staging systems to help them hone their treatment recommendations or make more specific predictions about your prognosis. 

TNM staging for oropharyngeal cancer

The TNM system, which is the most widely used staging system for throat cancer, is based on three key pieces of information about your cancer. 

  • Tumor (T) size: How large is it? Which tissues within the oropharyngeal cavity has it reached? 
  • Lymph node (N) involvement: Has the cancer spread to nearby lymph nodes? How many? Are they on the same side of the body as the primary tumor? 
  • Metastasis (M), or spread, to distant parts of the body: Has the cancer spread to other organs? 

Tumor (T)

When staging a cancer, doctors first look at the primary tumor – where the cancer started. The size, location, and whether it has spread into nearby areas all have an impact on the staging. 

Using this information, doctors assign a letter or a number to the T category, like this:

  • TX: There’s no information about the primary tumor or it can’t be measured.
  • T0: the cancer is limited to the epithelium (cells lining the oropharynx).  This may also be designated as Tis (carcinoma in situ).
  • T1-T4: A number after the T may describe the size of the tumor and/or how much it has spread to nearby areas. The higher the number, the larger the tumor or the more it has spread. This number might also be followed by a small a or b. T4a means the tumor has spread into nearby parts of the oropharynx, larynx (voice box), tongue muscle, hard palate, or nearby bones. In T4b, it might have spread to nearby bones, the base of the skull, or the area surrounding the carotid artery. 

Lymph node (N)

When cancer spreads to nearby lymph nodes, that can be a sign that it will eventually advance to more distant parts of the body, a process called metastasis. Doctors check the lymph nodes to see whether the cancer has already begun this type of spread.

Using information gathered about the lymph nodes, the doctor will assign a letter or number to the N category, like this:

  • NX: For whatever reason, the doctor has no information about the nearby lymph nodes or they cannot be checked for spread. 
  • N0: There’s no cancer in the lymph nodes. 
  • N1-N3: Numbers can describe the size of the lymph nodes affected by cancer, their location, or the number of nodes that the cancer has reached. The higher the number, the more the cancer has spread to nearby lymph nodes. 

Metastasis (M)

When cancer reaches other organs that are far away from the primary tumor, such as the lungs or brain, it has metastasized. That means the cancer is very advanced. 

Doctors assign a number in the M category:

  • M0: No metastasis 
  • M1: There is cancer in distant organs.

Oropharyngeal cancer staging by HPV status

Throat cancer stages also depend on whether the human papillomavirus (HPV) was the cause. The vast majority of oropharyngeal cancers are caused by HPV, but not all of them are. HPV-positive and HPV-negative cancers are biologically different diseases. 

"The presence of HPV significantly impacts the prognosis of oropharyngeal cancer. HPV-positive cancers generally have a better prognosis and are treated differently from HPV-negative cancers. The TNM system specifically addresses this by creating separate classifications for HPV-positive and HPV-negative tumors," says Maie St. John, MD, co-director of the UCLA Head and Neck Cancer Program. 

Numerical staging for oropharyngeal cancer

Your doctor will use the TNM staging information to assign your cancer a numbered stage from 0 or 1, the earliest stage, to 4. 

The lower numbers describe a cancer that is earlier in its development. That means the tumor is still relatively small or that it has not spread as far from the original site where it first arose. Higher numbers refer to larger tumors or cancers that have spread beyond the throat. The higher the number, the farther it has spread or the larger the tumor has grown. 

Cancer stages can include a letter and a number. The letter "A," for example, would represent a cancer that is at an earlier stage than "B."

Stage 1

The tumor is no larger than 4 centimeters (cm). If it has spread to the lymph nodes at all, they are on the same side of the neck as the primary tumor and none is larger than 6 cm. 

Stage 2

The tumor is no larger than 4 cm, and it has spread to one or more lymph nodes on the opposite side of the neck, but none is larger than 6 cm.

If the cancer has not spread to the lymph nodes, or has spread only to lymph nodes on the same side of the neck, it is still stage 2 if one of the following is true:

  • The tumor is over 4 cm.
  • It is growing into the base of the tongue, the voice box, the hard palate, or nearby bones.

Stage 3

The cancer has spread to at least one lymph node on the opposite side of the neck, but none is larger than 6 cm, and one of these is also true:

  • The tumor is larger than 4 cm.
  • It is growing into the base of the tongue, the voice box, the hard palate, the tongue muscle, or surrounding bones.

Stage 4

Any of the above can be true, but the cancer has also spread to distant areas, such as bones or lungs. 

 

HPV-negative throat cancers start with stage 0.

Stage 0

Also called carcinoma in situ, the tumor is still on the surface layer of cells lining the oropharynx.

Stage 1

The tumor is 2 centimeters (cm) or smaller.

Stage 2

The tumor is between 2 and 4 cm. It has not spread to nearby tissues or lymph nodes.

Stage 3

One of the following is true:

  • The tumor is larger than 4 cm.
  • The tumor is any size (and may have spread beyond the original site and into other parts of the oropharynx, such as the base of the tongue), and it has spread to one lymph node on the same side of the body as the primary tumor but not beyond that node, and the node is no larger than 3 cm. 

Stage 4a

The tumor is any size, and it is growing into nearby parts of the oropharynx, such as the voice box (larynx), the tongue, the hard palate, or bones in the area. 

One of the following is also true:

  • It hasn’t spread to the lymph nodes.
  • It has spread to only one lymph node that is no larger than 3 cm, on the same side of the body as the primary tumor, and not outside of that lymph node. 

Or the cancer is any size, has not spread to distant organs, but has spread to one of the following: 

  • One lymph node on the same side as the primary tumor, and the node is between 3 and 6 cm, but the cancer hasn’t grown outside of that node
  • More than one lymph node on the same side as the primary tumor, but not outside of any of those nodes, and none is larger than 6 cm
  • One or more lymph nodes either on the opposite side of the primary tumor or on both sides of the neck, but has not grown outside any of the lymph nodes and none are larger than 6 cm

Stage 4B

The cancer is any size and may have spread to nearby structures, and it has spread to at least one of the following: 

  • One lymph node that is larger than 6 cm, but hasn’t grown outside that node
  • One lymph node that is larger than 3 cm, and it has grown outside that lymph node
  • More than one lymph node on either or both sides of the neck, with growth outside the lymph nodes
  • One lymph node on the opposite side of the primary tumor that’s 3 cm or smaller and has grown outside of that lymph node
  • Nearby structures, such as the base of the skull or bones, or the area surrounding the carotid artery

Stage 4C

The cancer has spread to distant organs, such as the lungs.

"Oropharyngeal cancer staging describes the size of the tumor and whether it has spread to lymph nodes or other areas in the body, while grading describes how abnormal the cancer cells look under a microscope compared to healthy cells," says St. John. "Staging helps determine the extent of the cancer and its potential spread, while grading provides information about the cancer's aggressiveness and growth rate."

Cancer is graded by looking at the cancer cells under a microscope. The more they differ from normal throat cells, the riskier this cancer is. Grades for HPV-negative cancers are:

  • Grade 1/Low Grade: The cells look very similar to normal oropharyngeal cells.
  • Grade 2/Intermediate Grade: The cells look slightly different from normal cells.
  • Grade 3-4/High Grade: The cells look very abnormal or very different from normal cells.

Doctors can gather the information needed to stage throat cancers in two ways.

Clinical staging

If you are not going to have surgery to remove the tumor, the doctor will determine your cancer stage through physical examination, tests, and scans. 

Pathological staging 

Also called surgical staging, in this method, doctors determine the stage after removing the tumor and examining tissue from it in a laboratory. During surgery, the doctor can also find out how many lymph nodes are involved in the cancer. 

Typically, doctors will combine the clinical and pathological information to come up with the most precise staging.

Cancer is recurrent or relapsed if it comes back after it responded to treatment. Your doctor won’t restage the cancer in the same way as before. Instead, the recurrence will be classed as one of the following:

  • Local: It came back to the same place it started the first time.
  • Regional: It came back in tissues or lymph nodes close to where it first started. 
  • Distant: It came back in a part of the body that is far from where it first started. 

Oropharyngeal cancer staging is based on the size of the primary tumor and whether it’s reached surrounding tissue and structures in the local area. Staging is also based on whether and how much your lymph nodes are involved. It also takes into consideration whether the cancer has spread to more distant parts of the body, such as the lungs. Whether the cancer was caused by HPV also plays a part in staging.

What are the odds of having oropharyngeal cancer? 

The average lifetime risk of developing oropharyngeal cancer is 1 in 59 for men and 1 in 139 for women, but the risk is higher for people who have more risk factors, such as smoking, excessive drinking, and HPV, among other factors. 

What’s the prognosis for oropharyngeal cancer? 

About 70% of people with this type of cancer are still alive five years after diagnosis. But the prognosis will depend on things like the stage, your overall health, and whether the cancer is HPV-positive or HPV-negative.

Can a dentist see oropharyngeal cancer? 

"Yes, dentists are often the first health care professionals to identify potential oropharyngeal cancer during routine oral exams. They are trained to look for signs of oral and oropharyngeal cancers, including visible abnormalities like red or white patches, sores that don't heal, and lumps or swelling in the mouth and neck. If a dentist suspects cancer, they will refer the patient to a specialist for further evaluation and diagnosis," St. John says. 

Who diagnoses oropharyngeal cancer? 

Your primary care doctor or dentist might see the first signs of abnormal cells in your throat and refer you to a specialist, like an ear, nose, and throat doctor (ENT), who would further investigate and confirm the diagnosis.