Cancer: Grading and Staging

Cancer Classifications are based on the following characteristics:

• location within the body, presence of metastases (stage)
• microscopic cellular appearance, level of cell differentaiton (its grade)

Grading

Histologic grade refers to the level of cellular differentiation, how much the tumor cells resemble normal cells of the same tissue type. Nuclear grade refers to the size and shape of the cell nucleus in tumor cells. It is the percentage of tumor cells that are dividing

• Grade 1: tumors are well differentiated and cells closely resemble cells of their normal parent orgin
• Grade 2 and 3: intermediate in appearance, moderately or poorly differentiated
• Grade 4: are highly undifferentiated and anaplastic (cells have gone backwards in their development to an nonspecialized or embryonic state)

Staging

• staging is based on the extent of metastasis
• 3 guiding characteristics are often used

1) Tumor – T: refers to the size and physical extent of the tumor

2) Node – N: refers to number of lymph nodes that have been invaded by the tumor

3) Metastasis – M: refers to the presence or abscence of metastases of the tumor cells

this is abbreviated TNM

• The International TNM Staging System is often used

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri

US National Intitute of Health. National Cancer Institute. 2009. Tumor Grade. Retrieved July 27, 2009 from http://www.cancer.gov/cancertopics/factsheet/detection/tumor-grade