What is meant by “grades” of tumors?
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
