Stages of Prostate Cancer
The main tests used for clinical staging of prostate cancer are:
- Digital rectal exam
- PSA test
- Transrectal ultrasound
Digital Rectal Exam
The digital rectal exam (DRE) is a procedure in which the doctor inserts a gloved finger into the rectum to examine it and the prostate to look for an irregular or abnormally firm area. It helps to gauge tumor size. It may also show if the cancer has spread into nearby tissues.
PSA (prostate-specific antigen) tests are playing an increasingly common role in cancer staging. Elevated PSA levels in the blood correlate roughly with the:
- Volume of cancer in the prostate
- Stage and grade of the tumor
- Presence or absence of cancer metastases, or growths in other tissues.
Valuable information about tumor size and location can also be obtained from a transrectal ultrasound (TRUS) used to guide the biopsy needle in sampling abnormal areas of the prostate. TRUS uses an ultrasound probe inserted into the rectum to visualize the area on a screen.
The pathologist's evaluation of the biopsy samples also helps to establish the clinical stage (size and extent) of a cancer. The pathologist:
- Tallies how many of the tissue samples contain cancer
- Notes whether any of the samples are more than half cancerous
- Determines a Gleason score.