Once prostate cancer has been diagnosed, the next question is how far it has grown. This is called staging. Along with the Gleason score and PSA level, the stage helps doctors recommend the right treatment. Most UK teams use the TNM system, which describes the cancer in three parts.
What TNM stands for
- T (tumour): how far the cancer has grown within or beyond the prostate
- N (nodes): whether it has spread to nearby lymph nodes
- M (metastasis): whether it has spread to other parts of the body, such as the bones
Each letter is followed by a number, and sometimes a further letter, to give more detail.
The T stage
T1: the cancer cannot be felt during an examination or seen clearly on a scan. It is often found because of a raised PSA.
T2: the cancer is contained within the prostate. It may be divided further:
- T2a: in less than half of one side
- T2b: in more than half of one side
- T2c: in both sides
T3: the cancer has grown through the outer layer, or capsule, of the prostate:
- T3a: just outside the capsule
- T3b: into the seminal vesicles, the small glands next to the prostate
T4: the cancer has grown into nearby organs, such as the bladder or rectum.
The N and M stages
N0 means no cancer has been found in the lymph nodes. N1 means it has.
M0 means there is no sign of spread to distant parts of the body. M1 means there is, most often to the bones.
How the stage is worked out
Staging uses several sources of information:
- a rectal examination, to feel the prostate
- an MRI scan, to show the tumour and whether it has grown outside the gland
- a bone scan, CT scan or PSMA PET scan for men at higher risk of spread
Our article on combining MRI and PSMA PET scans explains how newer imaging can find small areas of spread.
Localised, locally advanced and advanced
Doctors often group stages into three broad categories:
- Localised: T1 or T2, N0, M0. The cancer is contained within the prostate.
- Locally advanced: T3 or T4, or N1. The cancer has grown just outside the prostate or into nearby lymph nodes.
- Advanced or metastatic: M1. The cancer has spread to other parts of the body.
How stage affects treatment
For localised cancer, options include active surveillance, robotic prostatectomy and radiotherapy. The choice depends on stage, grade, PSA, general health and personal priorities.
For locally advanced cancer, surgery or radiotherapy may still aim to cure the disease, often combined with other treatments such as hormone therapy.
For advanced cancer, treatment focuses on controlling the disease for as long as possible and managing symptoms. Many men live well for years with treatment.
NICE guidance on prostate cancer groups localised disease into risk categories that combine stage, grade and PSA.
Clinical and pathological stage
The stage given before treatment is the clinical stage. If you have surgery, the whole prostate is examined afterwards, which gives the pathological stage. This is usually written with a small "p", such as pT2. It is more precise and helps guide follow-up.
Understanding your own stage
Staging can sound technical, but each part simply answers a practical question: how big is the cancer, has it reached the lymph nodes and has it spread further? Ask your specialist to write down your full TNM stage, Gleason score and PSA. Prostate Cancer UK has helpful explanations to read at home. Our prostate cancer page explains the main treatments in more detail.
Professor Prokar Dasgupta can explain your stage and the options that suit you at The London Clinic. Please contact the clinic to arrange a consultation.