The TNM Staging System
The most
widely used system in the United States for staging prostate
cancer is called the TNM System. It describes the extent
of the primary tumor (T stage), the absence or presence
of spread to nearby lymph nodes (N stage) and the absence
or presence of distant spread, or metastasis (M stage).
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T
Stages
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T1: The tumor can't be felt during a digital rectal
exam, or seen by imaging studies, but cancer cells are
found in a biopsy specimen.
- T1a
cancers are found incidentally (by "accident"), when
benign tissue is removed during TURP
(transurethral resection of the prostate). Less
than 5 percent of the tissue removed is cancerous
and more than 95 percent is benign.
- T1b
cancers are also found incidentally during TURP, but
more than 5 percent of the tissue removed is cancerous.
- T1c
cancers are identified by biopsy performed because
of an elevated PSA.
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T2 : The tumor can be felt during a DRE and the cancer
is confined within the prostate gland.
- T2a:
The tumor involves no more than half of one lobe (right
or left side) of the prostate.
- T2b:
The tumor involves more than half of one lobe, but
not both lobes.
- T2c:
The tumor involves both left and right lobes.
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T3 : The tumor has extended through the prostatic
capsule (a layer of fibrous tissue surrounding the prostate
gland) and/or to the seminal vesicles (two small sacs
next to the prostate that store semen), but no other
organs are affected.
- T3a:
The tumor extends through one side of the prostatic
capsule, but has not spread to the seminal vesicles.
- T3b:
The tumor extends through both sides of the prostatic
capsule, but has not spread to the seminal vesicles.
- T3c:
The tumor has spread to the seminal vesicles
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T4:
The tumor has spread or attached to tissues next to
the prostate (other than the seminal vesicles).
- T4a:
The tumor has spread to the neck of the bladder, the
external sphincter (muscles that help control urination),
or the rectum.
- T4b:
The tumor has spread to the floor and/or the wall
of the pelvis.
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N
Stages
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Lymph node involvement |
N1
- 3: Any T stage with lymph node involvement
- N0:
Cancer has not spread to any lymph nodes.
- N1:
Cancer has spread to a single regional lymph node
(inside the pelvis) and is not larger than 2 centimeters
( inch).
- N2:
Cancer has spread to one or more regional lymph nodes
and is larger than 2 centimeters ( inch), but not
larger than 5 centimeters (2 inches).
- N3:
Cancer has spread to a lymph node and is larger than
5 centimeters (2 inches).
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M
Stages
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Metastasis to distant sites |
- M0:
The cancer has not metastasized (spread) beyond the
regional lymph nodes.
- M1:
The cancer has metastasized to distant lymph nodes
(outside of the pelvis), bones, or other distant organs
such as lungs, liver, or brain.
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The
Prostate Cancer pages of this Web site are part of the Comprehensive
Prostate Cancer Awareness Program (CPCAP), a major regional
effort to reduce the rates of death and illness caused by
prostate cancer in southwestern Pennsylvania. Funding for
CPCAP is provided by a grant from the Commonwealth of Pennsylvania.
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