What is the TNM classification for prostate cancer?

Updated: Mar 23, 2020
  • Author: Natasza M Posielski, MD; Chief Editor: E Jason Abel, MD  more...
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Answer

Answer

The clinical staging of prostate cancer was devised from the American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) system. Risk stratification is based on the clinical stage as well as the following pretreatment parameters:

  • Digital rectal examination (DRE) findings
  • Prostate-specific antigen (PSA) value
  • Biopsy findings
  • 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. [1]

The TNM classification for prostate cancer is provided below. [2]

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.


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