Basic definitions of these terms are provided by the NCI NIH Cancernet dictionary (http://cancernet.nci.nih.gov/dictionary.html)
Staging describes the extent of a cancer within the body, and how far the disease has spread from the original site to other parts of the body. All cancers are staged differently. For staging information on the various gyn cancers, follow the links provided for each cancer in our Resources section.
Tumor grade is determined by how abnormal the cancer cells appear when examined under a microscope, and their probable growth and spread tendencies. Each type of cancer is graded differently.
You are also likely to hear the term "differentiated", when discussing the tumor grade. This refers to how "different" the cancer cells are when compared to the normal cells of that same organ or tissue. Well-differentiated means they are still somewhat similar to the original cells of the specific organ or tissues and tend to grow slowly and spread at a slower rate. Moderately differentiated cells are less distinguishable and a little faster growing; poorly differentiated cells lack the structure and function of normal cells and grow more uncontrollably. Unidentifiable cells (i.e., the pathologist cannot easily identify their point of origin) are referred to as "anaplastic", or sometimes "undifferentiated". These cells also grow and divide rapidly.
Another way of describing grade is by using the numerals 1, 2, 3 and 4. The most "well-differentiated" cells are usually Grade 1, also referred to as "low-grade". Grade 4, the most advanced grade, is used to describe "undifferentiated" or "high-grade" tumors. An excellent fact sheet is found on the National Cancer Institute's web site.