Prostate cancer is officially classified into four main stages (I through IV), not five. However, each stage has substages, and stage IV is split into two distinct categories, IVA and IVB, which function quite differently from each other. That split is likely why you’ve seen references to “five stages.” Understanding what separates each stage comes down to three factors: how far the tumor has grown, how aggressive the cancer cells look under a microscope (the Gleason score), and your PSA level at diagnosis.
How Prostate Cancer Staging Works
Doctors use a system called TNM staging, which evaluates tumor size and spread (T), whether nearby lymph nodes are involved (N), and whether cancer has metastasized to distant parts of the body (M). But prostate cancer staging is unusual compared to most other cancers. It also folds in two additional pieces of information: your PSA blood level and your Grade Group, which is based on the Gleason score and rates how abnormal the cells look on a scale from 1 (slow-growing) to 5 (highly aggressive).
This means two people with the same size tumor can end up in different stages if their PSA levels or Gleason scores differ. A small tumor with a high Gleason score can be staged higher than a larger tumor with slow-growing cells.
Stage I: Small, Slow-Growing Tumors
Stage I prostate cancer is confined to the prostate and has the least aggressive profile. To qualify, a tumor must meet all three of these conditions: a Grade Group of 1 (Gleason score of 6 or less), a PSA below 10, and no spread to lymph nodes or distant sites. In many cases, the tumor is too small to feel during a digital rectal exam and was found only through a PSA test or biopsy done for another reason.
Because these cancers grow so slowly, active surveillance is a standard approach. That means regular PSA tests, periodic biopsies, and sometimes MRI scans to monitor for changes, rather than immediate surgery or radiation. The goal is to avoid side effects of treatment for a cancer that may never cause harm during a person’s lifetime.
Stage II: Still Confined, but More Concerning
Stage II cancer is still entirely inside the prostate, but one or more risk factors have increased. This stage is broken into three substages that reflect rising concern:
- Stage IIA: The Gleason score is still low (Grade Group 1), but the PSA has risen to between 10 and 20, or the tumor can now be felt in more than half of one side of the prostate.
- Stage IIB: The PSA is still under 20, but the cells are moderately aggressive (Grade Group 2, Gleason 3+4=7).
- Stage IIC: The cells look more abnormal under the microscope (Grade Group 3 or 4, Gleason 4+3=7 or Gleason 8), though the PSA remains under 20 and the cancer hasn’t spread beyond the gland.
The jump from IIA to IIC matters because it reflects increasingly aggressive cell behavior. Active surveillance may still be appropriate for some Stage IIA cancers, but by Stage IIC, treatment with surgery or radiation becomes a more common recommendation.
Stage III: Locally Advanced Disease
Stage III means the cancer has either grown more aggressive at the cellular level, pushed beyond the prostate wall, or both. It has three substages:
- Stage IIIA: The tumor is still inside the prostate, but the PSA has climbed to 20 or above. The Gleason score can be anywhere up to 8.
- Stage IIIB: The cancer has physically broken through the prostate capsule. This includes tumors extending into the tissue surrounding the prostate (called extraprostatic extension) or invading the seminal vesicles, the small glands that sit just behind the prostate.
- Stage IIIC: Regardless of tumor size or PSA, the cells are the most aggressive type, Grade Group 5 (Gleason 9 or 10). Even if the cancer hasn’t spread to lymph nodes, the biology of these cells puts them in a higher risk category.
Treatment at this stage typically involves a combination of radiation therapy and hormone therapy that lowers testosterone, since prostate cancer cells rely on testosterone to grow. Surgery is sometimes an option for Stage IIIA or IIIB, depending on the specifics.
Stage IVA: Spread to Nearby Lymph Nodes
Stage IVA means cancer has reached the lymph nodes near the prostate (in the pelvis), but has not traveled to distant organs. At this point, the PSA level and Gleason score no longer affect the stage classification. Any prostate cancer with positive regional lymph nodes is automatically Stage IVA.
This distinction matters because lymph node involvement signals the cancer has gained the ability to travel through the lymphatic system, but treatment can still be aggressive and curative in intent. Radiation combined with long-term hormone therapy is a common approach. According to SEER data covering 2016 through 2022, prostate cancer that has spread to regional lymph nodes still carries a 5-year relative survival rate of 100%, the same as cancer confined to the prostate itself.
Stage IVB: Distant Metastasis
Stage IVB is the most advanced classification and means cancer has spread to distant parts of the body. The most common sites are bones, distant lymph nodes (outside the pelvis), and the liver. Lung and brain metastases can occur but are less common. The staging system further subdivides distant spread: non-regional lymph nodes are classified as M1a, bone metastases as M1b, and spread to organs like the lungs, liver, or brain as M1c.
Bone is by far the most frequent destination. Metastases to the spine, pelvis, and ribs can cause deep, persistent pain that often brings patients to diagnosis in the first place. The 5-year relative survival rate for distant prostate cancer drops to about 40%, a significant change from the earlier stages.
Treatment at this stage focuses on controlling the disease and managing symptoms. Hormone therapy remains the backbone, often combined with newer targeted treatments. For cancers that initially respond to hormone therapy but later stop responding (called castration-resistant disease), additional options have expanded in recent years, including treatments that target cancer cells displaying a specific protein on their surface.
How Modern Imaging Is Changing Staging
A newer type of PET scan that targets a protein found on most prostate cancer cells has significantly improved the accuracy of staging. In one study comparing this advanced scan to conventional imaging (standard CT and bone scans), staging was altered in 48% of patients. Standard imaging detected distant metastases in 8% of patients, while the newer scan found them in 16%, double the rate. Twelve patients in the study were newly identified with distant spread that conventional scans missed entirely.
This means some cancers previously thought to be Stage II or III are actually Stage IV, and treatment plans change accordingly. If you’re being staged, it’s worth knowing whether your imaging included this newer scan type, as it can meaningfully affect your diagnosis and treatment path.
What the Survival Numbers Mean in Practice
The survival statistics for prostate cancer are among the most favorable of any cancer. For localized and regional disease (Stages I through IVA), the 5-year relative survival rate is 100%. That number comes from SEER data tracking patients diagnosed between 2016 and 2022. It doesn’t mean every person survives, but it means that as a group, people with these stages of prostate cancer are just as likely to be alive five years later as people without prostate cancer.
For distant metastatic disease (Stage IVB), the 5-year survival rate of about 40% reflects a harder road, but it has been improving as newer treatments become available. Many men with metastatic prostate cancer live well beyond five years, particularly when the disease responds to hormone-based therapies early on.