Cell Grading and Differentiation

< More of this Feature • Cancer 101 Introduction • Part 1:The Nature of Cancer • Part 2: A Guide to Gyn Tumor Types • Part 3:Dysplasia 101 • Part 5:Cancer Staging

by Laura Dolson

Sometimes on a biopsy report, you will see reference to the "grade" of the tumor, usually expressed in terms of a Roman numeral, most often I-III for gyn cancers. What does cell grading refer to?

First, it's easy to confuse the stage of the cancer and its grade. Stage refers to how far the tumor has invaded into its tissue of origin or progressed beyond it. We will go into detail about staging in part 5 of this series. Grade is about the cells themselves, and refers primarily to the amount of differentiation of the cells.

What is differentiation?

Differentiation refers to how different the tumor cells are from the cells from which they originated. For example, if the cells in a particular endometrial tumor look quite a lot like other endometrial cells, that would be grade I. If they look very different from the "normal" endometrium, that would be grade III, or "poorly differentiated." At the extreme, cells are so undifferentiated that a pathologist looking at them under a microscope cannot tell what tissue they originated from. These cells are also called anaplastic. Anaplastic cells from the breast, kidney, and uterus all look pretty much alike.

What causes some tumors to have poor differentiation?

Some cancer cells begin to multiply before they are fully mature. This causes disturbances, both in the shape and structure of the cell, and also possibly of the architecture of the tumor as a whole. The sooner the cells begin to divide, the "wilder" they become, both in the way they look, and in their behavior. Tumors that have a greater proportion of these rapidly-dividing cells will grow faster, and tend to spread earlier. Such cancer is said to be more aggressive.

What significance does the tumor grade have?

In general, higher grades have a poorer prognosis. However, there are so many factors that go into prognosis, that it cannot be said in any one case how important the grade is in predicting how well a person will do in the long run. Tumor type and staging are two of the other important factors, as well as a myriad of others. Another issue is that grading a tumor is not entirely an objective process. Different pathologists may disagree on the grade of any one tumor. Also, with ovarian cancer in particular, there are a lot of different systems of grading tumors, which can further add to the difficulty of knowing exactly what grading means in any one case.

Does the grade of the tumor make a difference in treatment?

At times, yes. For example for Grade I Stage 1 endometrial cancer, surgery may be the only treatment, while for a Grade 3 cancer, the physician may favor adding adjuvant therapy, such as radiation therapy.

Next> Staging Gyn Cancers

Copyright © 2001 by Laura Dolson. All rights reserved. Please submit reprint requests to gyncancer@baymoon.com

The material on this page and Web site is for informational and educational purposes only, and should not substitute for medical advice. Anyone having questions about the application of information appearing here to a specific person or situation should obtain advice from a qualified physician.