Stage & Grade
If you are diagnosed with prostate cancer, your doctor will discuss the stage and grade of your cancer with you.
Every cancer has a system of staging and grading that is specific to that type of cancer. Stage describes how advanced a cancer is. Grade describes how much or little it looks like normal tissue and how likely it is to spread. The stage and grade can help select the treatment and predict the prognosis of the cancer.
Stage. Prostate cancer is staged by the tumor, node, and metastasis (TNM) staging system. Staging may be clinical (using the digital rectal exam to check the feel of the prostate and imaging studies such as CT, MRI, or bone scan) or pathologic (looking at the prostate and lymph nodes under a microscope after they have been removed). The staging system for prostate cancer is described in the table below.
n T1 – Tumor is completely inside the prostate, and cannot be felt on DRE.
n T2 – Tumor is completely inside the prostate, but can be felt on DRE.
n T3 or T4 – Cancer has spread outside of the prostate
n N+ or M+ - Cancer has spread the lymph nodes (N+), or the bones or other organs (M+)
Grade. The most common grading system for prostate cancer is the Gleason score. It is based on how the tissue sample looks. The original system had grades 1 to 5. Grade 1 looks most like normal prostate tissue and grade 5 looks very different from normal prostate tissue. Because more than one pattern was frequently seen in a sample, the two most commonly seen patterns were added together to give you a Gleason score. For example 3+3=6. In the system that is now used, it is uncommon to see scores less than 6. Gleason 6 cancers are called low grade, Gleason 7 are intermediate grade, and Gleason 8, 9, and 10 cancers are high grade. Images of the grades may be seen below.