Prostate Cancer Stages and Grade

Prostate cancer is described in two ways: its stage and its grade. Stage tells how far the cancer has spread. Grade tells how aggressive the cancer cells look. Both matter, because some prostate cancers grow so slowly they can be watched instead of treated right away.

Staging looks at whether the cancer is confined to the prostate, has grown just outside it, or has spread to lymph nodes or distant sites such as bone. Stage I means a small, low-grade cancer confined to the prostate. Stage II covers cancer still confined to the prostate, but larger or higher-grade, divided into IIA, IIB, and IIC. Stage III means the cancer has grown outside the prostate, into the seminal vesicles or nearby tissue, or is a high-grade cancer even if still confined. Stage IV means the cancer has reached nearby lymph nodes, called stage IVA, or has spread to distant sites such as bone, called stage IVB.

The grade reflects how aggressive the cancer cells look under a microscope. Pathologists give a Gleason score, from 6 to 10, based on the two most common patterns of cells seen in the biopsy. A simpler system, called the Grade Group, translates this into a number from 1 to 5. Grade Group 1 matches a Gleason score of 6 and is the least aggressive. Grade Group 5 matches a Gleason score of 9 or 10 and is the most aggressive.

Stage tells how far it has spread; grade tells how aggressive it looks.

The PSA blood level, a protein made by the prostate, is considered alongside stage and grade. Lower PSA levels, generally under 10, are more reassuring. Higher levels, especially above 20, suggest more advanced or aggressive disease. Doctors use PSA together with stage and Gleason score or Grade Group to sort cancers into overall risk categories, which then guide treatment choices.

A low-stage, low-grade cancer, especially with a low PSA, often qualifies for active surveillance. This means closely monitoring the cancer with regular PSA tests, exams, and biopsies, and treating only if something changes. Many slow-growing prostate cancers can be safely watched this way for years. Higher-stage or higher-grade cancers usually call for treatment, such as surgery or radiation, sometimes combined with hormone therapy that lowers testosterone, since prostate cancer growth is often driven by this hormone.

Ask what your prostate cancer's stage is. Ask what your Gleason score or Grade Group is. Ask what your PSA level means combined with these results. Ask whether active surveillance is a reasonable option for you, or whether your risk category calls for treatment now.

Active surveillance involves regular PSA blood tests, periodic digital rectal exams, and follow-up biopsies, often supplemented with MRI imaging of the prostate. The goal is to catch any sign of the cancer becoming more aggressive early, while avoiding the side effects of surgery or radiation for a cancer that may never need them. Many men on active surveillance never need further treatment, though some do move to active treatment later if follow-up tests show a change.

• National Cancer Institute — Prostate Cancer Treatment (PDQ) Patient Version