What are the Stages of Prostate Cancer?
Prostate cancer – the most frequently diagnosed cancer for men in the United States, next to skin cancer – has four stages. Stage 1 is the earliest, meaning the cancer has not spread, and Stage 4 is the most advanced, showing spread to other areas of the body.
Understanding these stages of prostate cancer – as well as the diagnostic tests that determine those stages – offers insight into how quickly the cancer will grow and if treatment is recommended.
Table of Contents:
- About prostate cancer
- Clinical versus pathological staging
- How is prostate cancer staged?
- Defining the stages of prostate cancer
- Find support during a cancer journey
About prostate cancer
Prostate cancer occurs when cells in the prostate – a walnut-sized gland in men – develop DNA changes that make abnormal cells grow more quickly than normal cells. These abnormal cells combine to form a tumor. Sometimes, the tumor may grow quickly and cancerous cells spread to distant areas of the body. Other times, prostate cancer cells grow so slowly that they never become problematic. Often, men don’t experience symptoms of prostate cancer until later stages.
The American Cancer Society estimates that nearly 250,000 new prostate cancer cases will be diagnosed in 2021. Most people who have prostate cancer will not die of it, however, and the U.S. has more than 3 million Americans who are prostate cancer survivors. The five-year survival rate for prostate cancer is 98%.
Clinical and pathological staging
Prostate cancer has two types of staging. These types of staging allow doctors to learn more about a particular tumor, learning if cancerous cells are likely to spread, if treatment may be recommended, and how much the patient will be affected.
The first, clinical staging, can be done by a urologist. No surgery is required for clinical staging. These tests may include a physical examination, a prostate biopsy performed with a needle, as well as a prostate-specific antigen (PSA) test and a Gleason score. (Those will be covered more in the next section.) If results from clinical staging indicate that a surgery is needed to learn more about a tumor, then pathological staging will be done.
The second, pathological staging, follows a prostate surgery and reveals even more details about the tumor. Pathological staging includes the TNM staging system. (More information on TNM staging is below.)
How is prostate cancer staged?
Doctors combine the results of clinical and pathological tests to create an accurate staging of prostate cancer. This is what each test reveals, and how they’re used together:
TNM system
The most common system to stage cancer is the American Joint Committee on Cancer (AJCC)’s TNM system. The TNM system relies on three crucial pieces of information:
- T - Tumor: How big is the tumor? (This can be determined during the physical examination, a biopsy or imaging tests.)
- N - Nodes: How much has the cancer spread to nearby lymph nodes? (This is determined following a surgery to remove the prostate gland.)
- M - Metastasis: Has the cancer spread to distant parts of the body? (This, too, is determined following a surgery to remove the prostate gland.)
In addition, the TNM system incorporates additional pieces of information to create an accurate assessment of an individual’s case of prostate cancer, including a PSA test and a Gleason score.
PSA test
The TNM system also relies on levels of PSA, a prostate-specific antigen, which is a protein created by cells in the prostate gland. This test can be done by a health care provider drawing blood from a vein, likely in the arm. Normal cells and cancerous cells both create PSA, but higher levels of this antigen show a greater likelihood to develop prostate cancer. In addition to the risk of developing prostate cancer, PSA scores can also help a doctor determine the stage of the cancer.
The American Cancer Society offers the following guidance that relates PSA levels to risk of prostate cancer:
- PSA level under 4 ng/mL of blood: Low Risk — Patients who test below this level typically don’t have prostate cancer, but it is not a guarantee of being cancer free. Only about 15% of patients who test below this level will have prostate cancer, but a biopsy may be recommended for more definitive information.
- PSA level between 4 and 10 — Borderline Risk: Patients who test at this level have about a 25% chance of testing positive for prostate cancer.
- PSA level more than 10 — Higher Risk: With a PSA level greater than 10 ng/mL of blood, there is more than a 50% chance of having prostate cancer.
Gleason score
If cancer is detected during a prostate biopsy, the tumor will be assigned a score on the Gleason system. Gleason scores are divided into grade groups. Grade group 1 includes Gleason scores of 6 or less, showing the cancer is the slowest to grow or spread. These group numbers go up until grade group 5, which includes Gleason scores of 9 or 10, showing the cancer is most likely to grow or spread quickly.
Defining the stages of prostate cancer
Prostate cancer stage I
At this stage, cancer is on one side of the prostate. The PSA level and Gleason score are low, and there are no signs of spread to the lymph nodes or to distant areas. Stage 1 prostate cancer usually grows slowly. The five-year relative survival rate is nearly 100% for this stage of cancer.
Prostate cancer stage II
At this stage, the cancer is restricted within the prostate gland without any spread to the lymph nodes or distant areas. The cancer may either be on one or both sides of the prostate gland, and sub-stages (IIA, IIB, IIC) advance with higher PSA levels and Gleason scores. The five-year relative survival rate is nearly 100% at this stage.
Prostate cancer stage III
This is an advanced stage of cancer, in which the cancer may have spread to nearby tissue or is likely to grow and spread in the future. Depending on whether the cancer has grown beyond the prostate gland, this stage is divided into three sub-stages:
1. IIIA: Cancer hasn’t yet spread
2. IIIB: Cancer may have spread to tissues near the prostate, but it has not spread to lymph nodes or distant sites
3. IIIC: Cancer may have spread beyond the prostate, but it has not spread to lymph nodes or distant sites
In Stage III, when cancer spread is localized or regional, the five-year relative survival rate is nearly 100%.
Prostate cancer stage IV
In this advanced stage of cancer, the prostate cancer may have spread to distant areas, such as the lymph nodes, bone or organs. Stage IV has two substages:
1. IVA: Cancer has spread to nearby lymph nodes but not to distant sites
2. IVB: Cancer may have spread to other areas, including distant lymph nodes, bone or organs
Doctors will determine the extent of the spread through imaging tools, which may include biopsies of other tissues, CT scan, MRI or PET scan.
When the cancer has spread to distant sites, the five-year relative survival rate can be about 30%. Additional factors, including PSA levels, age and overall health, will influence outlook. Due to recent advancements in treatments, however, patients who are diagnosed with advanced prostate cancer now may have better outlooks than historical numbers represent.
Find support during a cancer journey
Receiving a cancer diagnosis can be an overwhelming and frightening time. We are here to help. AnMed Health offers a comprehensive, state-of-the-art cancer facility which has earned Accreditation with Commendation from the Commission on Cancer of the American College of Surgeons. In addition to expert medical care, we offer patients and their families our support and empathy throughout their cancer journeys.
To learn more about personalized cancer care at AnMed Health, visit our Cancer Care section or call 864.225.5131 to learn more.