Cancer Stages and Grades

Cancer is the name given to a collection of related diseases. In all types of cancer, some of the body’s cells begin to divide without stopping and spread into surrounding tissues.
Too many of us are aware of the prevalence of cancer in our society. Two words often come up, but are not universally understood. Staging is for the cancer itself and grade references the actual tumor. There are different grading systems for different types of cancer. For instance, there is Gleason for prostate cancer, Bloom-Richardson for breast cancer, Fuhrman for kidney cancer, etc.

Cancer stage refers to the size and/or reach of the original (primary) tumor and whether or not cancer cells have spread (metastasized) elsewhere in the body. Stages do not change from initial diagnosis, even if the cancer becomes more aggressive. This is important for consistent statistical analysis.

Stage 0 (zero) Abnormal cells are present, but have not spread to nearby tissue. Stages I, II, and III indicate cancer is present. The higher the number, the larger the cancer tumor and the more it has spread into nearby tissues. Stage IV shows the cancer has spread to distant parts of the body.
Staging is usually based on the TNM system of classifying cancer. In the TNM system, each cancer is assigned a letter or number to describe the tumor, node, and metastases. T stands for the original (primary) tumor. N stands for nodes and tells whether the cancer has spread to the nearby lymph nodes. M stands for metastasis.
Tumor grade is the description of a tumor based on how abnormal the tumor cells and tumor tissue looks under a microscope. There are four grades G1 Well differentiated (low grade), G2 Moderately differentiated (intermediate grade), G3 Poorly differentiated (high grade), and G4 Undifferentiated (high grade). Grade 3 and 4 tumors tend to grow rapidly and spread faster than tumors with a lower grade.

Low-grade cancer cells look more like normal cells and tend to grow and spread more slowly than high-grade cancer cells. Cancer grade may be used to help plan treatment and determine prognosis.
In addition, there are two tumor types, benign, such as moles and warts and malignant, where the cells invade the surrounding tissue and organs.

Generally, there are five cancer stages, four tumor grades, and two tumor types, benign and malignant. Unlike school, a high stage or grade is not good.