TNM – What is Staging? What does TNM Stand For?

  1. Staging, What is it? What does staging mean?
  2. Why are there so many numbers and letters?
  3. Why do doctors have to write in code?

If you’ve had a diagnoses of cancer you may have heard the term “staging”, this is when doctors carry out tests (things like scans, blood tests and x-rays) to try and work out exactly where a cancer is and if it has spread (or not.)

Why do they need to do this? It can help the doctors decide what is the best treatment to give you.

One type of staging is TNM, it is probably the most common as it’s used for tumours that form solid lumps. Generally the smaller the numbers the better (i.e. T1 is better than T2. M0 is better than M1)

A Quick Guide to TNM Staging

T – T means tumour (i.e. the letter T stands for tumour). It is usually followed by a number, usually the smaller the number the better, because a tumour 1 (T1) is smaller than a tumour 4 (T4) Note – T0 is proununced T zero (and not “to”) The 0 is the number zero (not the letter “o”)

N – N means node (i.e. the letter N stands for node), the N number can be from 0-3. Again the smaller the number the better, N0 means (as far as they can tell) the nodes aren’t affected. N3 means lots of nodes are affected. Nx means they don’t know if your nodes are involved or not. N0 is pronounced N zero (and not “no”). The 0 is the number zero (not the letter “o”)

What exactly is a node? A node is a “lymph node” your lymph nodes are also called your glands, they are all over your body. Lymph (pronunced lim-ff) is a watery fluid.

A lymph node

A lymph node

The Lymph System

M means metastasis (i.e. the letter M stands for metastasis). Usually tumours are M0 or M1. If doctors aren’t sure they call it Mx. M0 is pronounced M zero (and not “mo”). The 0 is the number zero (not the letter “o”)

Staging helps doctors work out what “stage” a cancer is at. Staging can have different names (e.g. TNM for solid tumours, Dukes for Bowel Cancer, Binet for chronic lymphocytic leukeamia CLL) it depends what type of cancer you have. Generally the smaller the numbers the better your prognosis. No one staging system is better than another. Your docotor will use the naming system that gives the most information for your type of tumour.

For a detailed explaniation of TMN staging and what the numbers and X’s mean have a look at Cancer Staging and Grading from BUPA, it also has a short 2 minute video animation showing how cancer develops, so you might need a broadband internet connection to see it. It was written in May 2014, so it is right up to date.

So why do doctors write in code? Well, as you can see, writing in code is a shorthand way of giving a lot of information in a small space and that’s why doctors use it. It’s quicker and easier than writing things out long hand and means the people treating you know a lot about your specific type of tumour, we need staging so we can give people the best (most appropriate) treament for their specific cancer.


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