Prostate cancer staging

Prostate cancer staging can be thought of in terms of physical location or grading histologically. The TNM classification is used to determine spread and the Gleason score is used to determine histological type. Another staging system is the Jewett-Whitmore staging system.

TNM staging

Primary tumour staging (T)

• T1 - not palpable via DRE or seen using TRUS
  • T1a - cancer found incidentally during TURP - less than 5% of the gland
  • T1b - cancer found incidentally but over 5% of the gland is involved
  • T1c - found by needle biopsy for a raised PSA
• T2 - palpable on DRE, but confined to the prostate
  • T2a - less than half of one side of the gland 
  • T2b - more than half of one side
  • T2c - cancer on both sides of the prostate
• T3 - spread outside the prostate
• T3a - tumour has extended outside of the prostate on one side.
• T3b - tumour has extended outside of the prostate on both sides.
  T3c - tumour has invaded one or both of the seminal vesicles, which are small bag-like organs near the bladder
• T4 - spread into the adjacent tissues
  • e.g. bladder spincter, rectum or pelvic side wall

Nodal status (N)

On CT a 1 cm short axis diameter cut off is used if its purely on size grounds ⁷.

• N0 - no spread to lymph nodes
• N1 - one or more nearby lymph nodes involved

Metastases (M)

• M0 - no spread beyond regional lymph nodes
• M1 - spread beyond local nodes
  • M1a - distant lymph nodes outside the pelvic
  • M1b - bony metastasis
  • M1c - other organ involvement independant of bony involvement
    • e.g. lungs, liver, brain 

Histopathologic grading

Gleason scores can be then grouped into a variety of grades:

• Gx - grade cannot be assessed
• G1 - well-differentiated (slight anaplasia) (Gleason score of 2-4)
• G2 - moderately differentiated (moderate anaplasia) (Gleason score of 5-6)
• G3-4  - poorly differentiated or undifferentiated (marked anaplasia) (Gleason score of 7-10)

Stage groupings

• stage I 
  • T1a, N0, M0, G1
• stage II
  • T1a, N0, M0, G2-4
  • T1b, N0, M0, any G
  • T1c, N0, M0, any G
  • T1, N0, M0, any G
  • T2, N0, M0, any G
• stage III
  • T3, N0, M0, any G
• stage IV
  • T4, N0, M0, any G
  • any T, N1, M0, any G
  • any T, any N, M1, any G

See also

• prostate cancer
  • Gleason score