The Tumor-Node-Metastasis (TNM) System

 

Stage (TNM)	Definition of Stage
T1    T1a    T1b    T1c	Not palpable, found following TURP or biopsy Focal, <5% of tissue, not high grade Diffuse, >5% of tissue, and/or high grade Biopsy for PSA elevation only
T2    T2a    T2b    T2c	Palpable disease limited to the prostate Disease < ½ of one lobe Disease > ½ of one lobe but < 1 lobe Disease > 1 lobe
T3    T3a    T3b    T3c	Palpable disease beyond the prostate Unilateral disease beyond the capsule Bilateral disease beyond the capsule Spread to seminal vesicles
T4	Metastatic spread to adjacent organs (e.g., bladder, pelvic sidewall)
Metastatic cancer	N+ Tumor that has spread to pelvic lymph nodes M+ Tumor that has spread beyond pelvic lymph nodes

TURP = transurethral resection of the prostate; PSA = prostate-specific antigen.

 

The Gleason Grading System

The Gleason histological scoring system, tumors are graded from one to five based upon the degree of glandular differentiation and structural architecture. Grade one represents the most well-differentiated appearance and grade five represents the most poorly differentiated. A primary score and a secondary score is then reported. The most differentiated cancers have a score of "one plus one" or two; the most undifferentiated cancers are scored as "five plus five" or ten. Combined scores (primary and secondary scores) of two, three, and four usually represent well-differentiated cancers; scores of five, six, or seven represent moderately differentiated cancers; and scores of eight, nine, or ten represent poorly differentiated cancers. The prognosis is directly related to the pattern score.

 

Grading System:

1 Simple round glands, closely packed in rounded masses with well-defined edges.

2 Simple round glands, loosely packed in vague, rounded masses with loosely packed edges.

3A Medium-sized single glands of irregular shape and irregular spacing with ill-defined infiltrating edges.

3B Very similar to 3A, but small to very small glands which must not form significant chains or cords.

3C Papillary and cribriform epithelium in smooth, rounded cylinders and masses; no necrosis.

4A Small, medium, or large glands fused into cords, chains or ragged, infiltrating masses.

4B Very similar to 4A, but with many large clear cells, sometimes resembling "hypernephroma."

5A No glandular differentiation, solid sheets, cords, single cells, or solid nests of tumor with central necrosis.

5B Anaplastic adenocarcinoma in ragged sheets.

 

References:

1. Rees MA, Resnick MI, Oesterling JE. Use of prostate-specific antigen, Gleason score, and digital rectal examination in staging patients with newly diagnosed prostate cancer. Urol Clin North Am. 1997 May;24(2):379-88. [Medline]

2. Gleason DF. Histologic grading of prostate cancer: a perspective. Hum Pathol. 1992 Mar;23(3):273-9. [Medline]