Prostate cancer staging

[6] Stage I disease is cancer that is found incidentally in a small part of the sample when prostate tissue is removed for other reasons, such as benign prostatic hyperplasia, and the cells closely resemble normal cells and the gland feels normal to the examining finger.

In Stage IV disease, the tumor has invaded nearby structures or has spread to lymph nodes or other organs.

The Gleason Grading System is based on cellular content and tissue architecture from biopsies, which provides an estimate of the destructive potential and ultimate prognosis of the disease.

[citation needed] Of note, this system of describing tumors as "well-", "moderately-", and "poorly-" differentiated based on Gleason score of 2–4, 5–6, and 7–10, respectively, persists in SEER and other databases but is generally outdated.

For example, it is common to classify patients into high, intermediate and low-risk groups on the basis of these three factors (TNM stage, PSA and Gleason score).

There is no clear division between stage, which has historically described the anatomic extent of disease at diagnosis, and prognostic models that may include many features that contribute to clinical outcome.

Although the role of surgery in these patients remains uncertain, those with high-risk disease are usually treated with radiotherapy and a long duration of hormonal ablation.

There may be adipose tissue within the prostate gland, but nevertheless, definite fat involvement by prostate cancer (as pictures) in a needle biopsy counts as extraprostatic or extracapsular spread. [ 7 ]
In contrast, skeletal muscle is normally present within the prostate, so involvement thereof does not count as extraprostatic or extracapsular extension. [ 8 ]