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Cancer Awareness GuideGeneral information & support

Cancer stages explained: what stage and grade mean

When someone is diagnosed with cancer, doctors describe its stage - how large it is and how far it has spread. This guide explains the common terms in plain language so a pathology report or a conversation with a doctor is easier to follow. It is general information only.

For information only - this is not medical advice. Only your own medical team can explain what your stage means for you. Please talk to your doctor about your results.

What does "stage" mean?

The US National Cancer Institute (NCI) defines stage as the extent of a cancer, such as how large the tumour is and whether it has spread (NCI: Cancer Staging). According to NCI, knowing the stage helps a doctor to:

  • understand how serious the cancer is and the likely outlook;
  • plan the most suitable treatment;
  • identify clinical trials that might be an option.

What doctors look at when staging

Staging systems differ between cancer types, but NCI explains that most of them take into account:

  • where the tumour is located in the body;
  • the size of the tumour;
  • whether the cancer has spread to nearby lymph nodes;
  • whether the cancer has spread to a different part of the body.

To work out the stage, doctors may use a physical exam, imaging such as x-rays or scans, lab tests and often a biopsy, in which a small sample of tissue is removed and examined under a microscope. NCI notes there is no single test that can diagnose cancer, and a biopsy is often the only way to tell for sure (NCI: How Cancer Is Diagnosed).

The TNM system

NCI describes TNM as the most widely used staging system, and the main one most hospitals use for cancer reporting. Each letter describes one part of the picture:

  • T (tumour) - the size and extent of the main, or primary, tumour. TX means it cannot be measured, T0 means it cannot be found, and T1 to T4 describe a larger tumour or one that has grown further into nearby tissue as the number rises.
  • N (nodes) - whether cancer is in nearby lymph nodes. N0 means no cancer in nearby nodes; N1 to N3 refer to the number and location of lymph nodes that contain cancer; the higher the number, the more nodes are involved. NX means this cannot be measured.
  • M (metastasis) - whether the cancer has spread to other parts of the body. M0 means it has not; M1 means it has. MX means this cannot be measured.

So a report might read something like T3N1M0. Letters such as "a" or "b" can be added for more detail. NCI notes that some cancers use their own staging systems instead, for example brain and spinal cord tumours and blood cancers, and that many staging systems are specific to one type of cancer. NCI adds that, where TNM is used, you are likely to see your cancer described this way in your pathology report.

How to read a TNM staging line, step by step

If you have been given a written report, these steps can help you follow the letters before you discuss them with your doctor. They use only the general meanings NCI gives above.

  1. Find the three letters T, N and M and the number or letter after each one, for example T3, N1 and M0.
  2. Read the T value as the size and extent of the main tumour: a higher number means a larger tumour or one that has grown further into nearby tissue. TX means it could not be measured.
  3. Read the N value as lymph node involvement: N0 means no cancer in nearby nodes, and N1 to N3 mean more nodes, or nodes further away, contain cancer. NX means this could not be measured.
  4. Read the M value as distant spread: M0 means the cancer has not spread to distant parts of the body and M1 means it has.
  5. Look for an overall stage, such as stage 2B, which groups the TNM details together.
  6. Write down what you do not understand and ask your care team to explain it. The exact meaning of each number depends on the type of cancer.

Stage 0 to stage 4

For many cancers, the TNM details are grouped into broader stages, which is how many doctors and nurses talk about them. NCI summarises them like this:

  • Stage 0 - abnormal cells are present but have not spread into nearby tissue. This is also called carcinoma in situ. NCI explains it is not cancer, but it may become cancer, which is why it is usually treated.
  • Stages 1, 2 and 3 (also written I, II and III) - cancer is present. The higher the number, the larger the tumour and the more it has spread into nearby tissues.
  • Stage 4 (IV) - the cancer has spread to distant parts of the body. For many cancers this is also called metastatic cancer - see what is metastatic cancer?

Stages can be divided further, for example 2A or 2B, to give more detail.

Localised, regional and distant

You may also hear a simpler set of words that NCI says is used mostly by cancer registries for statistics:

  • In situ - abnormal cells have not spread to nearby tissue.
  • Localised - cancer is limited to where it started.
  • Regional - cancer has spread to nearby lymph nodes, tissues or organs.
  • Distant - cancer has spread to distant parts of the body.
  • Unknown - there is not enough information to say.

Why the stage does not change

One point that often surprises people: NCI explains that a cancer is always referred to by the stage it was given at diagnosis, even if it later grows or spreads. New information is added to the original stage rather than replacing it. And when cancer spreads, it keeps its original name - breast cancer that spreads to the lung is still breast cancer, not lung cancer (NCI: Metastatic Cancer).

Stage is not the same as grade

Grade describes how normal or abnormal the cancer cells look under a microscope, while stage describes size and spread. NCI explains that most tumours are graded 1 to 4 (or X if the grade cannot be assessed). Grade 1 cells look closest to normal and tend to grow more slowly; higher grades look more abnormal and are more likely to grow and spread faster (NCI: Tumor Grade). A pathologist decides the grade from a biopsy sample, and different cancers use different grading factors.

Doctors use stage, grade and other information - such as genetic features of the tumour, a person's age and general health - together when planning care. No single number tells the whole story.

Questions you might ask about your stage

  • What is the stage and the grade, and what do they mean for my type of cancer?
  • Which tests were used to work out the stage, and are any results still to come?
  • Is my cancer staged with TNM or with a different system?
  • How does the stage affect the treatment options you are suggesting?

Your oncologist or specialist nurse is usually the best person to ask. If you are not sure which specialist does what, see what is an oncologist?

Using this information

Staging language can feel overwhelming. It is completely reasonable to ask your doctor to explain your stage and grade in plain words, or to write them down for you. Our list of questions to ask your doctor may help you prepare, and finding trusted support lists places to turn for help. For the basics of how cancer develops and spreads, see what is cancer?, and for the main cancer groups see common types of cancer. The tests used to find the stage are explained in how cancer is diagnosed, and the main approaches to care in types of cancer treatment.

Staging systems differ between cancer types, and general descriptions cannot predict any one person's outcome. Please do not use this page to interpret your own report - your medical team knows your full situation.

Sources

Published 15 October 2026. Last reviewed: 10 November 2026.

Common questions

What does TNM stand for?

T describes the size and extent of the main tumour, N describes whether cancer is in nearby lymph nodes, and M describes whether the cancer has spread (metastasised) to other parts of the body.

Is stage 0 cancer?

NCI describes stage 0, or carcinoma in situ, as abnormal cells that have not spread into nearby tissue. It is not cancer, but it may become cancer, so it is usually treated.

What is the difference between stage and grade?

Stage describes how large a cancer is and how far it has spread. Grade describes how abnormal the cells look under a microscope, which can suggest how quickly it may grow.

Can a cancer stage go down or change?

NCI explains that a cancer keeps the stage it was given at diagnosis, even if it changes later. New information is added to the original stage rather than replacing it.

Is stage 4 the same as metastatic cancer?

For many cancers, yes. NCI describes stage 4 (IV) as cancer that has spread to distant parts of the body, which for many types is also called metastatic cancer.

What do TX, NX and MX mean?

NCI explains that an X means that part could not be measured: TX for the main tumour, NX for nearby lymph nodes and MX for distant spread.