TNM Classification for Prostate Cancer
The clinical staging of prostate cancer was devised from the American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) system. [1] Risk stratification is based on the clinical stage as well as the following pretreatment parameters:
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Digital rectal examination (DRE) findings
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Prostate-specific antigen (PSA) value
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Biopsy findings
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Imaging study results
Pathological staging is determined following prostatectomy and depends on factors such as tumor burden, status of surgical margins, extracapsular disease, and seminal vesicle and pelvic lymph node involvement. Pathological staging is a more accurate measure of the extent of disease and allows for better prediction of outcomes. [2]
The TNM classification for prostate cancer is provided below. [3]
Table 1. TNM Classification for Prostate Cancer (Open Table in a new window)
Primary tumor (T) |
|
Clinical (cT) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence of primary tumor |
T1 |
Clinically inapparent tumor not palpable or visible by imaging |
T1a |
Tumor incidental histologic finding in ≤5% of tissue resected (at time of transurethral resection of the prostate [TURP]) |
T1b |
Tumor incidental histologic finding in >5% of tissue resected (at time of TURP) |
T1c |
Tumor identified by needle biopsy (because of elevated prostate specific antigen [PSA] level) |
T2 |
Tumor confined within prostate (Note: tumors found in 1 or both lobes by needle biopsy but not palpable on DRE or reliably visible by imaging are classified as T1c) |
T2a |
Tumor involves one-half of 1 lobe or less |
T2b |
Tumor involves more than one-half of 1 lobe but not both lobes |
T2c |
Tumor involves both lobes |
T3 |
Tumor extends through the prostatic capsule (Note: invasion into the prostatic apex, or into—but not beyond—the prostatic capsule is classified as T2 |
T3a |
Extracapsular extension (unilateral or bilateral) |
T3b |
Tumor invading seminal vesicle(s) |
T4 |
Tumor fixed or invades adjacent structures other than seminal vesicles (eg, bladder, levator muscles, and/or pelvic wall) |
Pathologic (pT)* |
|
pT2 |
Organ confined |
pT3 |
Extraprostatic extension |
pT3a |
Extraprostatic extension or microscopic invasion of the bladder neck** |
pT3b |
Seminal vesicle invasion |
pT4 |
Tumor is fixed or invades adjacent structures other than the seminal vesicles (eg, bladder, rectum) |
*There is no pathologic T1 classification. **Positive surgical margin should be indicated by an R1 descriptor (residual microscopic disease). |
|
Regional lymph nodes (N) |
|
Clinical (cN) |
|
NX |
Regional lymph nodes were not assessed |
N0 |
No regional lymph node metastasis |
N1 |
Metastasis in regional lymph node(s) |
Pathologic (pN) |
|
pNX |
Regional nodes not sampled |
pN0 |
No positive regional nodes |
pN1 |
Metastases in regional nodes(s) |
Distant metastasis (M)* |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
M1a |
Nonregional lymph nodes(s) |
M1b |
Bone(s) |
M1c |
Other site(s) with or without bone disease |
*If more than 1 site of metastasis is present, use the most advanced category. |
Histopathologic Grade for Prostate Cancer
An additional factor influencing prognosis is histopathologic grading. Tissue obtained from a needle biopsy or a prostatectomy is graded using the Gleason Grading System. Gleason grades range from 1 to 5. Each specimen is assigned two grades based on the most common and second most common pattern. These numerical values are added to calculate the Gleason Score.
Table 2. Gleason Score (Open Table in a new window)
Histopathologic grade (G) |
|
GX |
Gleason score cannot be assessed |
Gleason ≤6 |
Well differentiated (slight anaplasia) |
Gleason 7 |
Moderately differentiated (moderate anaplasia) |
Gleason 8-10 |
Poorly differentiated or undifferentiated (marked anaplasia) |
The 8th edition of the AJCC Cancer Staging Manual took effect on January 1, 2018. A major change is that tumor grading now involves the Gleason Score, as well as the grade group. [4]
Table 3. Grade Group (Open Table in a new window)
Grade Group | Gleason Score | Gleason Pattern(s) |
---|---|---|
1 | ≤6 | ≤3 + 3 |
2 | 7 | 3 + 4 |
3 | 7 | 4 + 3 |
4 | 8 | 4 + 4 (3+5/5+3) |
5 | 9 or 10 | 4 + 5, 5 + 4, 5 + 5 |
Risk Stratification
Prostate cancer risk stratification is based on groups defined by D’Amico et al in 1998. This system has been adopted by the National Comprehensive Cancer Network (NCCN) and is used widely in clinical practice when making decisions regarding treatment and/or active surveillance. [3, 5]
Table 4. Anatomic stage/prognostic groups (Open Table in a new window)
Stage* |
T |
N |
M |
PSA |
Grade Group |
|
I | cT1a-c, cT2a | N0 | M0 | < 10 ng/ml | 1 | |
pT2 | N0 | M0 | < 10 ng/ml | 1 | ||
IIA | cT1a-c, cT2a | N0 | M0 | ≥10, < 20 ng/ml | 1 | |
pT2 | N0 | M0 | ≥10, < 20 ng/ml | 1 | ||
cT2b-c | N0 | M0 | < 20 ng/ml | 1 | ||
IIB | T1-2 | N0 | M0 | < 20 ng/ml | 2 | |
IIC | T1-2 | N0 | M0 | < 20 ng/ml | 3 | |
T1-2 | N0 | M0 | < 20 ng/ml | 4 | ||
IIIA | T1-2 | N0 | M0 | ≥20 ng/ml | 1-4 | |
IIIB | T3-4 | N0 | M0 | Any | 1-4 | |
IIIC | Any | N0 | M0 | Any | 5 | |
IVA | Any | N1 | M0 | Any | Any | |
IVB | Any | Any | M1 | Any | Any | |
*If PSA or Gleason is not available, grouping should be determined by T stage and/or either PSA or Gleason, as available. |
See Prostate Cancer: Diagnosis and Staging, a Critical Images slideshow, to help determine the best diagnostic approach for this potentially deadly disease.
Also see the Advanced Prostate Cancer: Signs of Metastatic Disease slideshow for help identifying the signs of metastatic disease.