How is prostate cancer classified?
Prostate cancer is classified by its grade and stage. • Grade describes how the cancer (malignant) cells look and act compared to normal prostate cells. Higher-grade cells are more likely to grow rapidly and spread to other parts of the body (metastasize). • Stage describes how much the cancer has grown and spread.
Prostate cancer is characterized by both grade and stage. Grade is a term used to describe how closely a tumor resembles normal tissue. Based on the microscopic appearance of a tumor, pathologists (doctors who identify diseases by studying tissues under a microscope) may describe it as low-, medium-, or high-grade cancer. One way of grading prostate cancer, called the Gleason system, uses scores of 2 to 10. Another system uses G1 through G4. The higher the score, the higher the grade of the tumor. High-grade tumors grow more quickly and are more likely to spread than low-grade tumors. Staging of prostate cancer means determining the site and location of the disease. Early prostate cancer, stages 1 and 2, is localized to the prostate gland. Stage 3 prostate cancer is locally advanced outside the gland. Stage 4 prostate cancer has spread to other organs or tissues.
