18.2 – Oncology Diagnostic Tools
A biopsy examines the lesion, growth or tumour under a microscope to determine the disease. Once the pathologist determines the issue is malignancy, then grading, staging and metastasis are evaluated.
Grading, Staging and Metastasis
Tumours are also graded as per growth and staged as per the cancer cell spreading.
Grading: Pathologists need to know how different a cancer cell is from a normal one: this is called grading. It is a measure of the severity of cancer. Grading ranges from I to IV, or low grade and high grade. Generally, a lower grade represents a more favourable prognosis.
- Staging: Includes the size and spread of cancer from its original site. If it is determined from a pathology report, it is called pathologic staging. If diagnostic techniques determine it, it is called clinical staging.
- TNM staging: Stands for tumour, node, metastasis.
- T– indicates the size of the primary tumour and the degree of spread into nearby tissues (local invasion)
- N– indicates whether or not cancer has spread to nearby lymph nodes, the size of the nodes that contain cancer, and how many lymph nodes are affected.
- M– The cancer cells have spread to other organs, called metastasis or Mets.
Once the TNM is determined for particular cancer, an overall stage is determined. The stage ranges from 0 to IV (0–4). These numbers help identify whether the cancer is early or advanced. The higher the number, the more advanced cancer:
- stage 0 –carcinoma in situ (cancer appears only at the site and has not spread).
- stages I and II –the cancer is limited to the organ or location where it began, or it may have spread to a nearby structure (localized spread).
- stage III –cancer has spread further into a surrounding structure or to the regional lymph nodes (regional spread).
- stage IV –cancer has spread to a distant site in the body (metastatic spread).
Watch How is Cancer Staged? (4 min) on YouTube
Media 18.3: Cancer Center. (2018, August 8). How is cancer staged? [Video] YouTube. https://youtu.be/-pHilR4dtoA
Attribution
This page “Oncology Diagnostic Tools” by Connie Stevens and Marie Rutherford is licensed under CC BY 4.0.