Do you know the difference? So important to know this: A cancer’s grade describes how abnormal the cancer cells and tissue look under a microscope when compared to healthy cells. Cancer cells that look and organize most like healthy cells and tissue are low grade tumors. Doctors describe these cancers as being well differentiated. Lower grade cancers are typically less aggressive and have a better prognosis.
The more abnormal the cells look and organize themselves, the higher the cancer’s grade. Cancer cells with a high grades tend to be more aggressive. They are called poorly differentiated or undifferentiated.
Some cancers have their own system for grading tumors. Many others use a standard 1-4 grading scale.
Grade 1: Tumor cells and tissue looks most like healthy cells and tissue. These are called well-differentiated tumors and are considered low grade.
Grade 2: The cells and tissue are somewhat abnormal and are called moderately differentiated. These are intermediate grade tumors.
Grade 3: Cancer cells & tissue look very abnormal. These cancers are considered poorly differentiated, since they no longer have an architectural structure or pattern. Grade 3 tumors are considered high grade.
Grade 4: These undifferentiated cancers have the most abnormal looking cells. These are the highest grade and typically grow and spread faster than lower grade tumors.