After the level of aggressiveness of your prostate cancer is estimated (see Gleason Score), the next step, called staging, estimates if or how far the cancer has spread. The older ABCD system of staging prostate tumors has largely been replaced by the TNM (Tumor, Nodes, Metastases) system, which gauges the severity of cancer on an escalating scale.
- T stands for tumor and signifies the extent of the cancer in — and adjacent to — the prostate gland.
- N stands for nodes (lymph nodes) and signifies whether the cancer has — or has not — spread to nearby lymph nodes.
- M stands for metastasis, the medical term for cancer that has spread to other tissues or organs, such as the bone or the lungs.
These three letters are followed by a number and perhaps another letter in small type. The numbers range from 0 to 4 and represent the extent of the tumor. The small letters go from a to c and indicate some subtype of information, as described on the chart below.
Stage T1
Tumor is microscopic and confined to prostate but is undetectable by a digital rectal exam (DRE) or by ultrasound. Usually discovered by PSA tests or biopsies.
Stage T2
Tumor is confined to prostate and can be detected by DRE or ultrasound.
Stage T3 or T4
In stage T3, the cancer has spread to tissue adjacent to the prostate or to the seminal vesicles. Stage T4 tumors have spread to organs near the prostate, such as the bladder.
Stage N+ or M+
To each of the TNM stages above may be added an N,M, or G.
Cancer has spread to pelvic lymph nodes (N+) or to lymph nodes, organs, or bones distant from the prostate (M+).
The N is for lymph nodes. NX means that the lymph nodes cannot be assessed.
N0 means the lymph nodes are not involved.
N1 is a single lymph node, 2 cm or less.
N2 means metastasis in a single lymph node greater than 2 cm or multiple lymph nodes with sum greater than 2 cm.
N3 indicates lymph with greater than 5 cm metastasis.
M is for metastasis.
MX means that distant metastasis cannot be assessed.
MO means no distant metastasis,
M1a is nonregional lymph nodes,
M1b is bone metastasis,
M1c is other sites.
Primary tumor (T)
| TX | Tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| T1 | Clinically not palpable or visible by imaging |
| T1a | Found incidental to other surgery; present in 5% or less of tissue |
| T1b | Found incidental to other surgery; present in 5% or more of tissue |
| T1c | Identified by needle biopsy |
| T2 | Tumor confined within prostate |
| T2a | Involving half a lobe or less of prostate |
| T2b | Involving half a lobe |
| T2c | Involving both lobes |
| T3 | Tumor extends through prostate capsule |
| T3a | Extends through one lobe |
| T3b | Extends through both lobes |
| T3c | Extends into seminal vesicles |
| T4 | Involves structures other than seminal vesicles |
| T4a | Invades bladder neck, external sphincter, or rectum |
| T4b | Invades muscles and/or pelvic wall |
Regional Lymph Nodes (N)
| NX | Nodes cannot be assessed |
| N0 | No regional node metastasis |
| N1 | Single node metastasis, 2 centimeters (cm) or less at largest point |
| N2 | Single node metastasis, 2 cm to 5 cm at largest point, or multiple nodes, no larger than 5 cm at largest point |
| N3 | Metastasis larger than 5 cm in any node |
Distant Metastasis (M)
| MX | Metastasis cannot be assessed |
| M0 | No distant metastasis |
| M1 | Distant metastasis |
| M1a | Distant lymph node(s) involved |
| M1b | Bone(s) involved |
| M1c | Other site(s) involved |