How does prostate cancer spread?
Prostate cancer is the abnormal growth of cells in the prostate gland. Your doctor can tell what stage prostate cancer is in by performing a digital rectal exam, PSA test, and imaging.
If you are diagnosed with prostate cancer, your doctor will check how much it has spread. This process is known as staging. Prostate cancer stages show how much cancer is in your body and how it affects you. Doctors plan your treatment based on the prostate cancer stage.
Prostate cancer is the abnormal growth of cells in the prostate gland. If undetected, cancer can spread outside the prostate. It invades and grows into other tissues and spreads through your lymph vessels. It can also travel to other parts through blood, known as metastasis.
How do doctors identify prostate cancer stages?
After diagnosis, your doctor will do a biopsy to study the prostate cancer cells. They’ll also do some tests to check cancer cells and whether cancer has spread. Your doctor will use any of these screening tests to check the prostate cancer stage:
- Digital rectal exam (DRE). It is done to check if the prostate is hard or enlarged.
- Prostate-specific antigen (PSA). High levels of PSA protein indicate cancer.
- Imaging. Transrectal ultrasound (TRUS) and prostate MRI are imaging tests to check the growth and spread of prostate cancer.
What is the TNM System for prostate cancer stages?
Doctors use the tumor, node, and metastasis or TNM system to identify prostate cancer stages. The system uses three factors of tumor growth and spread to figure out the stage:
- Tumor. Your doctor will check the size of the tumor in your prostate gland.
- Nodes. They’ll check if it has spread to any lymph nodes.
- Metastasis. They’ll check if the prostate cancer has spread to other body parts.
What are prostate cancer stages?
Doctors combine the results of the TNM system, the Gleason score, and the PSA test to figure out the stage. This is called stage grouping.
Prostate cancer stages include:
Stage I
Cancer starts growing in your prostate. But it can’t be detected during a DRE or imaging test. The tumor grows in one half or lesser than a side of the prostate, the Gleason score is 6 or less, and the PSA level is less than 10.
Stage IIA
The cancer is growing but hasn’t spread outside the prostate. The doctor may detect it during a DRE, TRUS, or imaging test. The tumor grows in one half or more than half a side of the prostate. But it doesn’t affect both lobes. The Gleason score is 6 or less. The PSA level is less than 20.
Stage IIB
The cancer is growing in your prostate but hasn’t spread yet. The doctor may detect it during a DRE, TRUS, or imaging test. The tumor can be in one or both lobes of the prostate. The Gleason score is 7. The PSA level is less than 20.
Stage IIC
The cells look more different than those in stage IIB. Cancer grows but doesn’t spread outside the prostate. The doctor may detect it during screening tests. The tumor can be in one or both lobes. The Gleason score is 7 or 8. The PSA level is less than 20.
Stage IIIA
Cancer doesn’t spread outside the prostate or to lymph nodes. The doctor may detect the tumor during screening tests. The Gleason score is 7 or 8. The PSA level is 20 or more.
Stage IIIB
Cancer starts to spread beyond the prostate but not to the lymph nodes or other parts. The Gleason score is 7 or 8. The PSA level can be any value.
Stage IIIC
Cancer may spread outside the prostate but doesn’t spread to the lymph nodes. The Gleason score is 9 or 10, and the PSA level can be any value.
Stage IVA
Cancer may spread to tissues and lymph nodes near the prostate. But it doesn’t spread far in the body. The Gleason score and PSA can be any value.
Stage IVB
Cancer may spread to tissues or lymph nodes near the prostate. It may spread to other body parts such as bones, lymph nodes, and other organs. The Gleason score and PSA can be any value.
Outlook
The 5-year relative survival rate for prostate cancer stages I to IVA is more than 99%. You’ll have a 99% chance of surviving 5 years after your cancer diagnosis, compared to when you didn’t have cancer. Your expected lifespan will be similar to that of the general population.
However, if the cancer stage is IVB and it spreads to other body parts, the 5-year relative survival rate can decrease to 31%. Survival rates help you see how likely your treatment succeeds based on the cancer stage. This is why cancer screening, grading, and staging are important. It can help doctors diagnose your condition, find the best treatment for you, and improve your survival rate.
