Chapter 091. Benign and Malignant Diseases of the Prostate (Part 4) potx

PIN is a precursor of cancer, but not all PIN lesions develop into invasive cancers.. Of the cancers identified, >95% are adenocarcinomas; the remainder are squamous or transitional cel

Chapter 091 Benign and Malignant

Diseases of the Prostate

(Part 4)

Pathology

The noninvasive proliferation of epithelial cells within ducts is termed

prostatic intraepithelial neoplasia PIN is a precursor of cancer, but not all PIN

lesions develop into invasive cancers Of the cancers identified, >95% are adenocarcinomas; the remainder are squamous or transitional cell tumors or, rarely, carcinosarcomas Metastases to the prostate are rare, but in some cases colon cancers or transitional cell tumors of the bladder invade the gland by direct extension When prostate cancer is diagnosed, a measure of histologic

aggressiveness is assigned using the Gleason grading system, in which the

dominant and secondary glandular histologic patterns are scored from 1 (well-differentiated) to 5 (un(well-differentiated) and summed to give a total score of 2–10 for each tumor The most poorly differentiated area of tumor (i.e., the area with the

highest histologic grade) often determines biologic behavior The presence or absence of perineural invasion and extracapsular spread are also recorded

Prostate Cancer Staging

The TNM staging system includes categories for cancers that are palpable

on DRE, those identified solely on the basis of an abnormal PSA (T1c), those that are palpable but clinically confined to the gland (T2), and those that have extended outside the gland (T3 and T4) (Table 91-1) DRE alone is inaccurate with respect

to the extent of the disease within the gland, the presence or absence of capsular invasion, involvement of seminal vesicles, and extension of disease to lymph nodes Because of the inadequacy of DRE for staging, the staging system was modified to include the results of imaging studies Unfortunately, no single test has proven to indicate accurately the stage or the presence of organ-confined disease, seminal vesicle involvement, or lymph node spread

Table 91-1 Comparison of Clinical Stage by the TNM Classification System and the Whitmore-Jewett Staging System

TNM

Stage

Description

Whitmore-Jewett Stage

Description

T1a Nonpalpable,

with 5% or less of

resected tissue with

cancer

differentiated tumor on few chips from one lobe

with >5% of resected

tissue with cancer

more diffuse

detected due to elevated

serum PSA

T2a Palpable, half of

one lobe or less

lobe, surrounded by normal tissue

T2b Palpable, > half

of one lobe but not both

lobes

lobe

T2c Palpable,

involves both lobes

entire lobe or both lobes

unilateral extracapsular extension

outside capsule, not into seminal vesicles

bilateral extracapsular extension

seminal vesicle(s)

involved

metastases

disease

Source: Adapted from FF Schroder et al: TNM classification of prostate

cancer Prostate (Suppl) 4:129, 1992; and American Joint Committee on Cancer,

1992