What Are the Stages and Grades of Cancer?

The majority of cancers have four stages, stage 1 to stage 4; some cancers have a stage 0. The grade of a cancer details how much the cancer cells resemble healthy cells when viewed under a microscope and helps predict how fast a cancer may spread. Tumors with cells that closely resemble healthy cells are referred to as "low-grade" or "well-differentiated." Tumors with cells that less closely resemble healthy cells are called "high-grade," "poorly differentiated" or "undifferentiated," according to Cancer.net.

In stage 0, cancer is located in the place that it began and has not spread to surrounding tissues or organs, explains Cancer.net. Cancers in this stage are usually very curable, with treatment typically involving surgical removal of the cancer.

Stage 1 cancer, often referred to as "early-stage cancer," refers to a small tumor that hasn't grown deeply into surrounding tissues or spread throughout the body, states Cancer.net. Stage 2 and stage 3 cancers are larger and may have grown deeply into surrounding tissues or spread to lymph nodes. Stage 4 cancer, also called metastatic cancer, is the most advanced stage of cancer. It indicates that the cancer has spread to other organs or areas of the body.

Doctors use the stages of cancer to plan treatment, predict the chance of recovery, predict the likelihood of the cancer coming back after treatment and discuss the diagnosis in clear language, states Cancer.net.