Diagnosis

revised Mar. 2001

3.1 Clinico-pathologic Considerations

The most common histology is adenocarcinoma (acinar) and is dealt with in this guideline. The large duct (previously referred to as endometrioid) variant of prostate carcinoma is generally treated like the more common acinar type of prostatic adenocarcinoma, but as it may behave more aggressively and can be confused pathologically with transitional carcinoma, its presence should be specifically mentioned. Transitional cell carcinoma may be primary or secondary from the bladder and should be treated according to the bladder carcinoma recommendations. Pathologists need to delineate whether the transitional carcinoma invades prostate stroma, merely shows pagetoid extension into prostate ducts or involves tissue in prostate sample that may only represent bladder neck.

Other rare cancers include small cell carcinoma, which requires referral for combined modality therapy. Sarcomas are rare, occurring in younger patients and are dealt with by the Sarcoma Group.

3.2 Classification Criteria

Abnormal DRE and/or elevated PSA are not diagnostic of prostate cancer but place patients into a higher risk group for having cancer, who require further investigation. Diagnosis is confirmed by needle biopsy, most accurately using transrectal ultrasound guided sextant biopsies. Indications for biopsy include:

  • Elevated serum PSA above the age-specific range in an otherwise fit man
  • Suspicious digital rectal examination (asymmetry, nodules, or induration)
  • More accurate evaluation of stage T1a tumours detected on TUPR in fit men under 70 years of age

3.3 Diagnostic Pathology

  1. Pathologists can greatly assist patient management by providing the following information on needle biopsies:
    1. A comment regarding the adequacy of the specimen, particularly if only stroma sampled
    2. The presence or absence of carcinoma including an estimate of the amount of tumour (length of positive core in millimetres), location, and number of positive cores
    3. The histologic type
    4. The histologic grade - Gleason Grades 1-5 and Gleason Score, which is the sum of the two most prevalent grades
    5. The presence of vascular, lymphatic, or perineurial invasion
    6. Invasion into or extension beyond the prostatic capsule into fat
    7. Presence of low vs. high-grade prostatic intraepithelial neoplasia (PIN)
  2. Reports on transurethrally resected specimens should include the same information required for needle biopsy specimens, and clearly indicate extent (and Gleason grade) of involvement to differentiate T1a vs. T1b carcinomas. An estimate of the percent tissue volume that the carcinoma involves should be stated. Cases around the threshold carcinoma volume of 5% should be sampled liberally for microscopy
  3. Radical prostatectomy specimens should be inked and marked at all excisional margins and these should be sampled generously. Obvious tumour should be sampled and random sections of apparently normal prostatic tissue should be taken with particular emphasis at the apex, bladder neck, and peripheral inked margins. Pathology reports should include the following information:
    1. The presence or absence of carcinoma
    2. The size of carcinoma with measurement of at least the largest dimension and preferably all three dimensions.
    3. The location within the prostate, including presence of bilateral involvement
    4. The histologic type
    5. The histologic Gleason grade and score
    6. The presence of PIN
    7. The presence of invasion of lymphatics and/or veins
    8. Presence of extracapsular extension and comment on specific location and extent of extracapsular involvement
    9. Status of resection margins, including comment of specific margin(s) involved, extent of involvement and nature of tissue at involved margin, i.e. incised prostate parenchyma, capsule or fat
    10. Seminal vesicle wall invasion
    11. Nodal metastases, including number of nodes examined, number involved the size of involvement, and presence of extra nodal extension
    12. Comment about extent and degree of pretreatment effect