What is the grade and stage of prostate cancer?

 

If you compare cancer to a house on fire, grade is the temperature of the fire and stage is the number of rooms that have been affected.

 

The grade of cancer refers to the microscopic appearance of the cells.  Once a biopsy is taken of the cancer, it is examined through a microscope.  It is assessed using the Gleason Pattern System.  The Gleason pattern is scored from 1 to 5.  1 is the most favourable appearing type of cancer and 5 is the least favourable.  It is based on the most common pattern in the cancer.  The 2 most predominant patterns are added to give a Gleason score out of 10.

 

The stage of cancer depends on its size and the extent to which it has spread to other parts of the body.  Complete staging may only be possible after surgery, or additional tests are complete, and it may be necessary to remove some lymph nodes near the cancer to get a true picture.

 

The actual stage of the cancer is described using a common TMN system.  It is a combination of letters and numbers that look somewhat like a postal code – T1N2M0 – when used.  The T stands for tumour, and the number following it indicates the size of the tumour.  The N stands for nodes, and the number following it indicates the extent to which the lymph nodes are involved.  The M stands for metastases, and the number following it indicates the amount of spread to other parts of the body.  For prostate cancer, metastases indicate the spread of prostate cancer to the bones in 90% of the cases.  Other sites of spread include the lungs and liver. 

 

     Stage T1-T1c                Stage T2-T2c    

      

  Stage T3                   Stage T4

    

 

TMN	Description of Staging
T0	No evidence of tumour
T1a	The prostate feels completely normal but cancer found while examining prostate tissue biopsy for other reasons.  Tumour involving 5% or less of the tissue being examined.
T1b	The prostate feels completely normal but cancer found while examining prostate tissue biopsy for other reasons.  Tumour involving more than 5% of the tissue being examined.
T1c	The prostate feels completely normal but cancer is found because of an elevated PSA.
T2a	Cancerous tumour involving only half or less of one prostate lobe.
T2b	Cancerous tumour involving more than half of one lobe, but not both lobes of the prostate.
T2c	Cancerous tumour involving both lobes of the prostate.
T3a	Cancerous tumour that has extended beyond the prostate into the capsule (the covering on the prostate)
T3b	Cancerous tumour that has extended beyond the prostate into, and through, the capsule (the covering on the prostate).
T3c	Cancerous tumour that has extended beyond the prostate and has spread to one or both seminal vesicles.
T4a	Cancerous tumour has spread to bladder neck and/or external sphincter and/or rectum.
T4b	Cancerous tumour has spread to additional areas close to the prostate.
N0	No cancer in the lymph nodes.
N1	Cancer has spread to a single lymph node
M0	No distant metastasis (cancer spread)
M1	Distant metastasis present in bone or elsewhere

*Diagrams: Decision Aid for Prostate Cancer Treatment Abbott Laboratories, Limited – Oct.1999