What does the term differentiation refer to in the context of the ICD-O-3?

Differentiation in the context of the ICD-O-3 refers to the degree to which a tumor's cells resemble the normal cells of the tissue from which they originated. High differentiation indicates that the tumor cells look and behave more like normal cells, which often correlates with a better prognosis. Tumors that are well-differentiated tend to grow more slowly and are less aggressive than poorly differentiated tumors, which may bear little resemblance to the normal tissue and tend to grow and spread more rapidly.

Understanding differentiation is crucial for accurately classifying tumors and determining the appropriate treatment options and potential outcomes. It plays a significant role in the staging and grading of tumors, which are critical components in cancer diagnosis and management.