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Staging Resources

Staging information helps improve the cancer system because it is used for planning and managing cancer services, and for evaluating, measuring and reporting on cancer treatment patterns and outcomes. Guidelines and process information available here support healthcare providers involved in the staging process.

What Is Cancer Stage?

Cancer stage refers to the extent of a cancer patient’s disease. For instance, a patient diagnosed with early stage breast cancer may be classified as having Stage I disease, while a patient diagnosed with advanced breast cancer may be classified as having Stage IV disease. Knowing a patient’s cancer stage at diagnosis is critical in determining a prognosis, and helps both healthcare providers and patients make informed treatment decisions.

The Components of Cancer Stage

Clinical stage is based on all of the information obtained before definitive treatment starts, such as a physical examination, radiologic examination, endoscopy and biopsy. Pathologic stage is based on a pathologist’s analysis of tissue samples from a surgery to remove the tumour.

TNM staging was developed by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC). It is the global standard used by clinicians to assess the extent or severity of cancer at diagnosis. T stands for the size and extent of the tumour, N for the lymph nodes involved and M for metastasis, or the spread of the cancer to other parts of the body.

For answers to any questions or concerns about privacy, please refer to the Collaborative Staging Privacy FAQs.

Staging Guidelines and Processes


Find guidance on staging cancer patients for clinical care purposes and data reporting requirements of Ontario’s cancer care providers.


Healthcare providers can learn more about the process for stage reporting and TNM staging.

For more information on cancer stage or staging resources, please email