TNM classification of prostate tumours

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TNM classification of prostate tumours

Prostate

(ICD-0 C61)

Rules for classification

The classification applies only to adenocarcinomas. Transitional cell carcinoma of the prostate is classified as a urethral tumour (see UICC TNM Classification of Malignant Tumours, sixth edition1, page 203). There should be a histological confirmation of the disease.

The following are the procedures for assessing T, N and M categories:

• T categories Physical examination, imaging, endoscopy, biopsy and biochemical tests
• N categories Physical examination and imaging
• M categories Physical examination, imaging, skeletal studies, and biochemical tests

Regional lymph nodes

The regional lymph nodes are the nodes of the true pelvis, which are essentially the pelvic nodes below the bifurcation of the common iliac arteries. Laterality does not affect the N classification.

TNM clinical classification*

T	Primary tumour
TX	Primary tumour cannot be assessed
T0	No evidence of primary tumour
T1	Clinically inapparent tumour not palpable or visible by imaging
	T1a	Tumour incident histological finding in 5% or less of tissue resected
	T1b	Tumour incident histological finding in more than 5% of tissue retracted
	T1c	Tumour identified by needle biopsy (eg because of elevated PSA)
T2	Tumour confined within prostate#
	T2a	Tumour involves one half of one lobe or less
	T2b	Tumour involves more than half of one lobe, but not both lobes
	T2c	Tumour involves both lobes
T3	Tumour extends through the prostatic capsule^
	T3a	Extracapsular extension (unilateral or bilateral)
	T3b	Tumour invades seminal vesicles(s)
T4	Tumour is fixed or invades adjacent structures other than seminal vesicles: bladder neck, external sphincter, rectum, levator muscles, or pelvic wall

Notes:

^# Tumour found in one or both lobes by needle boipsy, but not palpable or visible by imaging, is classified as T1c.

^{^} Invasion into the prostatic apex or into (but not beyond) the prostatic capsule is not classified as T3, but as T2.

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N	Regional lymph nodes
	NX	Regional lymph nodes cannot be assessed
	N0	No regional lymph nodes metastasis
	N1	Regional lymph node metastasis

Notes:

Metastasis no larger than 0.2cm can be designated as pN1mi. (see Introduction, pN, page 10.)

M	Distant metastasis
	MX	Distant metastasis cannot be assessed
	M0	No distant metastasis
	M1	distant metastasis
	M1a	Non-regional lymph nodes(s)
	M1b	Bone(s)
	M1c	Other site(s)

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pTNM Pathological classification

The pT, pN, and pM categories correspond to the T, N, and M categories.

However, there is no pT1 category because there is insufficient tissue to assess the highest pT category.

G Histopathological grading

GX	Grade cannot be assessed
G1	Well differentiated (slight anaplasia) (Gleason 2-4)
G2	Moderately differentiated (moderate anaplasia) (Gleason 5-6)
G3-4	Poorly differentiated/undifferentiated (marked anaplasia) (Gleason 7-10)

Stage grouping

Stage I	T1a	N0	M0	G1
Stage II	T1a	N0	M0	G2,3-4
	T1b,c	N0	M0	Any G
	T1,T2	N0	M0	Any G
Stage III	T3	N0	M0	Any G
Stage IV	T4	N0	M09	Any G
	Any T	N1	M0	Any G
	Any T	Any N	M1	Any G

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Summary

Prostate
T1	Not Palpable
:T1a	<5%
:T1b	>5%
:T1c	Needle biopsy
T2	Confined within prostate
:T2a	<half one lobe
:T2b	>half one lobe
:T2c	both lobes
T3	Through prostatic capsule
:T3a	extracapsular
:T3b	seminal vesicle(s)
T4	Fixed or invades adjacent structures: bladder neck, external sphincter, rectum, levator, muscles, pelvic wall
N1	Regional lymph node(s)
M1a	Non-regional lymph node(s)
M1b	Bone(s)
M1c	Other site(s)

*Since these guidelines have been developed the UICC have published the seventh edition of TNM Classification of Malignant Tumours. There is no material difference in the definition of the T-, N-, and M-categories, however, there are some differences in stage grouping and risk grouping. See the table below:

T1 Not palpable or visible T1a     <5% or less T1b    >5% T1c    Detected by needle biopsy   T2 Confined within prostate T2a   < half of one lobe T2b   > half of one lobe T2c    Both lobes   T3 Through prostate capsule T3a   Extracapsular T3b   Seminal vesicle(s)   T4 Fixed or invades adjacent structures No change from 6th

STAGE GROUPING (ANATOMIC)       (UICC)   Stage I     T1, T2a    N0 Stage II    T2b-2c     N0 Stage III   T3             N0 Stage IV   T4            N0                  Any T       N1                  Any T      Any N       M1       Change from 6th Grade was in 6th

PROGNOSTIC GROUPING

I      T1a – c    N0     PSA <10        Gle < 6         T2a         N0     PSA <10         Gle < 6   IIA  T1 a – c   N0     PSA < 20        Gle 7         T1 a – c   N0    PSA >10 <20  Gle <6         T2a,b       N0    PSA >10 < 20 Gle < 7       If PSA or Gleason is missing, use whatever is available

IIB     T2c        N0      Any PSA     Any Gle            T 1-2     N0      PSA >20     Any Gle            T 1-2     N0      Any PSA    Gle > 8   III      T3a-c     N0      Any PSA    Any Gle IV      T4          N0     Any PSA    Any Gle           Any T    N1     Any PSA    Any Gle           Any T   Any N M1 Any PSA Any Gle   If both missing, no prognostic grouping is possible

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