Prostate Cancer (cont.)
What is Prostate Biopsy Procedure?
When the findings of the physical exam, DRE, and PSA level, suggest that a cancer might be present in the prostate, the diagnosis must be confirmed by biopsy (taking a sample of the tumor). The sample of tumor tissue is then examined by a pathologist, (doctor who specializes in diagnosing diseases by microscopic evaluation) to confirm the presence of cancer.
Main indication for prostate biopsy:
- Suspicious prostate exam with DRE
- Abnormal PSA level
- Abnormal change in PSA or PSA velocity
According to AUA guidelines there is no single threshold value of PSA that should prompt biopsy. Although the decision to take a biopsy is to be based primarily on PSA and DRE, it should take into consideration other factors such as PSA velocity, family history, ethnicity, prior biopsy results, and underlying medical conditions.
- Prostate biopsy is usually performed in an office as an outpatient procedure. The biopsies are obtained using a needle inserted through the rectum using transrectal ultrasound (TRUS) guidance while the patient is under local anesthesia.
- Local anesthetic is injected around the periphery of the prostate to reduce discomfort associated with prostate biopsy.
- TRUS imaging guides collection of the tissue sample.
- Tissues samples are systematically collected by inserting a needle into the tumor and withdrawing tissue. Typically 10 to 12 pieces of tissue are extracted from different parts of the prostate gland to look for the presence of cancer in the entire prostate.
- Most commonly, in preparation for the procedure, patients are administered a fluoroquinolone antibiotic and given a cleansing enema.
- Major complications, such as bleeding and/or infection requiring hospitalization are rare; however, hematuria (blood in the urine) and hematospermia (blood in the semen) are common sequelae of the procedure.
Pathology biopsy results:
- A pathologist examines biopsy pieces under the microscope to assess the type of cancer present in the prostate and the extent of involvement of the prostate with the tumor. One can also get an idea about the areas of the prostate that are invaded with the tumor by assessing which of the pieces contain the cancer and which of them do not.
- Another very important assessment that the pathologist makes from the specimen is the grade (Gleason score) of the tumor. This indicates how different the cancer cells are from normal prostate tissue.
- Grade gives an indication of how fast a cancer is likely to grow and has very important implications on the treatment plan and the chances of cure after treatment. A Gleason score of 6 generally indicates low grade (less aggressive) disease while that of 8 to 10 suggests high grade (more aggressive) cancer. A grade of 7 is regarded as somewhere in between these two.
What is Prostate Cancer Workup?
If cancer is present on biopsy, workup for metastasis may be indicated. Imaging studies may reveal the size and location of the tumor in the prostate as well as the extent of spread of the disease.
- Chest X-ray film: To detect whether or not cancer has spread to the lungs.
- Technetium Tc 99m bone scan: This test provides an image of the entire skeleton after a mildly radioactive substance is administered into a vein. The radioactive substance highlights areas where the cancer has affected the bones. This test is usually reserved for men with prostate cancer who have deep bone pain or a fracture or who have biopsy findings and high PSA values (>10 to 20 ng/mL) suggestive of advanced (metastatic) or aggressive disease.
- CT scan or MRI of abdomen and pelvis: This is the best way to detect the extent of the primary cancer as well as distant metastases. Pelvic CT or MRI may be considered to assess lymph node metastasis or when PSA >20 ng/mL, Clinical stage T3 to T4, or Gleason score ≥8.
- Endorectal coil MRI: The use of an endorectal probe with MRI can improve spatial resolution and thus better assess the likelihood of seminal vesicle involvement or extension beyond the prostate in men who are thought to have localized prostate cancer.
- Transrectal ultrasonography (TRUS): TRUS can be used to assess the local extension of prostate cancer. Three-dimensional TRUS provides more information about the location and extent of prostate cancer with the prostate gland compared to two-dimensional imaging. However TRUS is not an accurate method for localizing early prostate cancer and is not recommended for use in prostate cancer screening. The primary role of TRUS in prostate cancer detection and diagnosis is to ensure accurate sampling of prostate tissue by prostate biopsies.
- Ultrasound of kidneys, bladder, and prostate: Ultrasonography can be used to look for the effects of a urinary blockage on the kidneys. This is indicated by signs of swelling within the kidney (hydronephrosis) or swelling of the ureters (hydroureteres). This study can also be used to assess the bladder for any sign of urinary obstruction due to prostate enlargement by looking at the thickness of the bladder wall and the amount of urine left inside the bladder after passing urine.
- Cystoscopy: This is a test that uses a thin, flexible, lighted tube with a tiny camera on the end that is inserted through the urethra to the bladder. The camera transmits images to a video monitor. This may show whether or not the cancer has spread to the urethra or bladder. This exam doesn't always require general anesthesia.
Medically Reviewed by a Doctor on 11/22/2016
Pierre-Alain Hueber, MD, PhD
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