What is the TNM cancer staging system?

Published by the Union for International Cancer Control, the TNM Classification of Malignant Tumours (TNM) is a globally recognised standard for classifying the extent of spread of cancer. 

The classification of cancer by anatomic disease extent, i.e. stage, is the major determinant of appropriate treatment and prognosis. Stage is an increasingly important component of cancer surveillance and cancer control and an endpoint for the evaluation of the population-based screening and early detection efforts.

UICC has maintained and published the UICC TNM Classification of Malignant Tumours for over 70 years. The UICC TNM classification is the internationally accepted standard for cancer staging.

The UICC TNM Classification is an anatomically based system that records the primary and regional nodal extent of the tumour and the absence or presence of metastases.


What does TNM stand for?

Each individual aspect of TNM is termed as a category:

  • T category describes the primary tumour site and size
  • N category describes the regional lymph node involvement
  • M category describes the presence or otherwise of distant metastatic spread







The TNM Classification of Malignant Tumours, 8th Edition, published in 2016 provides the latest, internationally agreed-upon standards to describe and categorize cancer stages and progression.

Why adopt the TNM Classification?

The UICC TNM staging system is the common language in which oncology health professionals can communicate on the cancer extent for individual patients as a basis for decision making on treatment management and individual prognosis but can also be used, to inform and evaluate treatment guidelines, national cancer planning and research.

More specifically, the objectives of the TNM classification are the following:

  • Aid treatment planning,
  • Provide an indication of prognosis,
  • Assist in the evaluation of treatment results,
  • Facilitate the exchange of information between treatment centres,
  • Contribute to continuing investigations of human malignancies,
  • Support cancer control activities, including through cancer registries.

The TNM classification is a unified standard and is a prerequisite for ensuring the quality of care in all resource-settings. It goes beyond clinician practice and constitutes vital information for policy-makers developing or implementing cancer control and prevention plans and it is therefore important to include the TNM classification as part of cancer registration.

Any question?

Please download the FAQ's page for answers to your questions on cancer staging. If you do not find the answer to your question, you can contact the TNM helpdesk:

You can also read the documents:

Last update: 
Thursday 13 October 2022