Updated October 2025

Appendix 1.9 – Ontario Health (CCO) Staging Guidelines

Reporting of Cancer Stage at Diagnosis by Ontario Regional Cancer Centres

Introduction

The appropriate management of a patient with cancer is not possible without knowledge of the extent or stage of the cancer at time of diagnosis. Stage information constitutes one of the most important prognostic factors for cancer treatment. Reliable stage information also supports healthcare providers, administrators, researchers and decision-makers in their planning, evaluation, and quality improvement activities meant to enhance the patient experience and to advance patient outcomes.

Clinicians stage all cancer patients as part of a routine assessment and treatment plan. The staging standard currently in use by physicians in North America and officially adopted in Canada for patients diagnosed from January 1, 2018, onwards, is the American Joint Committee on Cancer Tumor Nodes Metastases (AJCC TNM) classification.

Ontario Health (Cancer Care Ontario) promotes the use of stage data in the development and reporting of cancer system indicators to facilitate surveillance of prognostically similar groups of cancer; to assess treatment patterns and guideline concordance; to inform decision making processes; and to support stage data quality improvement efforts.

Stage at Diagnosis is defined as the classification of patients with cancer into prognostically similar groups according to the extent of disease at the time of initial diagnosis. All patients undergoing diagnostic work-up for cancer are assigned a Clinical Stage (c) to develop a treatment plan. If the patient has definitive surgical treatment, the managing physician then assigns a Pathological Stage (p). If the patient receives neoadjuvant, or pre-surgical, systemic treatment or radiation therapy, followed by surgical resection of the primary cancer, the managing physician assigns a Post Therapy Pathological Stage (yp) to indicate the response to treatment. It should be noted that Canadian cancer registries, including the Ontario Cancer Registry, do not require collection of Post Therapy Clinical Stage (yc). Healthcare providers are responsible for documentation in the patient’s medical record of the cancer stage work up, test results, subsequent treatment, and all relevant findings.

Stage Data Submission Process

Regional Cancer Centres (RCCs) are required to submit AJCC TNM stage data to Ontario Health (CCO) for all stageable types of cancer, EXCLUDING Breast, Cervix, Colorectal, Lung, and Prostate. The Ontario Cancer Registry has been mandated to stage Breast, Cervix, Colorectal, Lung, and Prostate cancer, in compliance with Canadian Cancer Registry standards (operated by Statistics Canada) and the Canadian Partnership Against Cancer. This collaborative approach, combining OCR and RCC data, is meant to avoid a duplication of effort.

A stageable cancer case is one that is…

diagnosed or treated at the reporting facility (analytic) See also Appendix 1.16
considered reportable by Surveillance, Epidemiology, End Results (SEER) Program See Page 14 seer.cancer.gov/manuals/2025/SPCSM_2025_MainDoc.pdf https://seer.cancer.gov/manuals/2025/SPCSM_2025_Appendix_E.pdf#search=reportability
has a staging schema in the AJCC TNM classification See also Appendix 1.31 and Appendix 1.32

The Annual Cancer Surgery Quality Based Procedures Funding Agreement, signed between Ontario Health, and partner hospitals, outlines the responsibilities of regional cancer centres including…

ensuring that all eligible cancer patients are staged according to the Pan-Canadian endorsed standard, AJCC TNM 8th Edition beginning January 1, 2018 and AJCC TNM Version 9 for specific cancers as released. See table below.
providing Ontario Cancer Registry stage analysts with direct remote access to hospital electronic health records for the purpose of conducting cancer chart reviews.
appointing a ‘stage physician lead’, and a ‘health records stage lead’ to serve as single a point of contact with the Ontario Cancer Registry.
submitting stage at diagnosis for all invasive and in-situ cancers, with an AJCC stage schema, to Ontario health on a monthly basis via Databook ALR Reporting within 6 to 10 months from the date of diagnosis.

AJCC 8th Edition Staging Schema/AJCC Version 9 Protocol by Diagnosis Year

Primary Site	AJCC TNM Version 9 Effective Date
Diffuse Pleural Mesothelioma	January 1, 2025
Lung	January 1, 2025
Nasopharynx	January 1, 2025
Thymus	January 1, 2025
NET Appendix	January 1, 2024
NET Colon and Rectum	January 1, 2024
NET Duodenum and Ampulla of Vater	January 1, 2024
NET Jejunum and Ileum	January 1, 2024
NET Pancreas	January 1, 2024
NET Stomach	January 1, 2024
Vulva	January 1, 2024
Appendix	January 1, 2023
Anus	January 1, 2023
Brain & Spinal Cord	January 1, 2023
Cervix	January 1, 2021
AJCC TNM Schema	AJCC TNM 8th Edition
All Other Sites	January 1, 2018

https://www.facs.org/quality-programs/cancer-programs/american-joint-committee-on-cancer/ajcc-staging-online/

https://www.facs.org/quality-programs/cancer-programs/american-joint-committee-on-cancer/version-9

NB: To verify the eligibility of a case for AJCC TNM staging, based on the topography and histology codes, refer directly to the Chapter in the AJCC TNM8 Staging Manual and/or the AJCC TNM version 9 protocol, depending on the diagnosis year.

Stage Education

Stage queries can be sent to oh-cco_ocrquestions@ontariohealth.ca

Cancer stage training reference materials for cancer registrars and physicians are available on the AJCC website at:

https://www.facs.org/quality-programs/cancer-programs/american-joint-committee-on-cancer/staging-education/registrar/curriculum/