Prostate cancer is classified into four stages based on how far the tumor has grown and whether it has spread beyond the prostate. Stage I is the most contained, with cancer confined to a small area of the prostate, while Stage IV means cancer has reached distant parts of the body like the bones or liver. Each stage is determined by a combination of factors: the size and extent of the tumor, PSA blood levels, and a grade group score that reflects how aggressive the cancer cells look under a microscope.
How Prostate Cancer Is Staged
Doctors use a system called TNM staging, which stands for Tumor, Nodes, and Metastasis. The “T” describes how large the tumor is and whether it’s grown outside the prostate. The “N” indicates whether cancer has reached nearby lymph nodes. The “M” tells whether it has spread to distant organs. These three factors, combined with PSA levels and a grade group score, determine the overall stage from I to IV.
The grade group score (ranging from 1 to 5) replaced the older Gleason score as the primary way to describe how abnormal cancer cells appear. Grade Group 1 means the cells still look mostly like normal prostate tissue and tend to grow slowly. Grade Group 5 means the cells look very abnormal and are more likely to grow and spread quickly. The Gleason score is still reported alongside the grade group: Grade Group 1 corresponds to a Gleason score of 6 or less, while Grade Group 5 corresponds to Gleason scores of 9 or 10.
To figure out the stage, doctors may use several imaging tools. An MRI can reveal suspicious areas within the prostate itself. A PSMA PET scan uses a radioactive tracer that sticks specifically to prostate cancer cells, making it effective at detecting cancer that has spread to lymph nodes or other organs. Transrectal ultrasound, where a small probe is inserted into the rectum, creates detailed images of the prostate gland and is often used during biopsy.
Stage I: Cancer Confined to a Small Area
In Stage I, cancer exists only within the prostate and is small enough that it usually can’t be felt during a digital rectal exam. It’s typically discovered through a needle biopsy prompted by elevated PSA levels, or found incidentally during surgery for another condition like an enlarged prostate. The PSA level is below 10, and the grade group is 1 (Gleason score of 6 or less), meaning the cells look relatively normal and grow slowly.
In some Stage I cases, the tumor can be felt during a rectal exam, but only if it takes up half or less of one side of the prostate. The same PSA and grade group thresholds apply.
Because Stage I prostate cancer grows slowly and stays confined, treatment options range from active surveillance (monitoring with regular PSA tests, exams, and biopsies) to surgery that removes the prostate entirely, or radiation therapy. Many men with Stage I cancer do well with active surveillance alone, with treatment starting only if the cancer shows signs of progressing.
Stage II: Still Confined, but More Concerning
Stage II cancer remains inside the prostate but shows signs of being larger or more aggressive than Stage I. It’s divided into three substages based on how much of the prostate is involved, the PSA level, and the grade group.
- Stage IIA: The tumor is in half or less of one side of the prostate with a PSA between 10 and 20 and Grade Group 1, or it’s found in more than half of one side (or both sides) with a PSA under 20 and Grade Group 1.
- Stage IIB: Cancer is in one or both sides of the prostate. PSA is under 20, and the grade group is 2 (Gleason score 3+4=7), meaning most of the tissue still looks fairly normal but a smaller portion has more abnormal patterns.
- Stage IIC: Cancer is in one or both sides of the prostate. PSA is under 20, but the grade group is 3 or 4 (Gleason score of 4+3=7 or 8), indicating a higher proportion of abnormal-looking cells.
The jump from IIA to IIC reflects increasing aggressiveness. Treatment options mirror those for Stage I, including active surveillance, surgery, and radiation. However, as the grade group rises through Stage IIC, doctors are more likely to recommend definitive treatment rather than monitoring alone.
Stage III: Cancer Grows Beyond the Prostate
Stage III marks a significant shift. The cancer may have grown through the outer wall of the prostate or into nearby structures, or the cells themselves have become highly aggressive even if the tumor hasn’t visibly spread.
Stage III is also divided into substages. In Stage IIIA, the cancer may still be within or near the prostate, but the PSA has risen to 20 or above, signaling more disease activity. In Stage IIIB, the tumor has physically extended beyond the prostate into the seminal vesicles (glands that produce part of the semen) or into nearby organs like the bladder, rectum, or pelvic wall. Stage IIIC is defined by the grade group reaching 5 (Gleason 9 or 10), meaning the cancer cells look highly abnormal, regardless of whether the tumor has grown beyond the prostate.
Treatment at this stage typically becomes more aggressive. External radiation therapy combined with hormone therapy is a common approach. Surgery to remove the prostate is still an option for some men, often followed by radiation. Hormone therapy, which lowers testosterone levels to slow cancer growth, plays a central role at this stage. For men who aren’t candidates for aggressive treatment, active surveillance with hormone therapy if the cancer progresses remains a possibility.
Stage IV: Cancer Has Spread
Stage IV prostate cancer means the disease has spread beyond the prostate and its immediate surroundings. This can mean spread to nearby lymph nodes (Stage IVA) or to distant parts of the body (Stage IVB). The most common sites for distant spread are bones, lymph nodes outside the pelvis, liver, and lungs. Less commonly, prostate cancer reaches the adrenal glands, brain, or pancreas.
Bone metastasis is particularly common and often causes pain in the back, hips, or pelvis. When prostate cancer spreads to bones, treatments aimed at strengthening bone and reducing fracture risk become part of the care plan alongside cancer-directed therapy.
Treatment at Stage IV focuses on controlling the cancer’s growth and managing symptoms. Hormone therapy is the backbone of treatment and is often combined with chemotherapy. Radiation can target specific areas causing pain or other problems. A specialized form of radiation therapy that uses alpha-emitting particles can target cancer that has spread to bones. For men with slow-growing Stage IV disease or other health concerns, watchful waiting with hormone therapy as needed is also an option.
Survival Rates by Stage
The survival outlook for prostate cancer depends heavily on how far it has spread at diagnosis. According to the National Cancer Institute’s SEER database (using data from 2016 to 2022), men diagnosed with localized prostate cancer, meaning it’s confined to the prostate, have a five-year relative survival rate of 100%. The same is true for regional disease, where cancer has reached nearby lymph nodes but hasn’t gone further.
For distant prostate cancer, where the disease has spread to bones or other organs, the five-year relative survival rate drops to about 40%. These numbers are averages across large populations and don’t predict any individual’s outcome. Newer treatments, particularly targeted therapies and advanced imaging that catches spread earlier, continue to improve outcomes for men diagnosed at every stage.
The vast majority of prostate cancers are caught early. Localized and regional cases together account for the largest share of diagnoses, which is why prostate cancer’s overall survival statistics are among the most favorable of any cancer type.