When is a biopsy recommended?
A prostate biopsy should be performed only after several tests indicate sufficient risk of a clinically significant prostate cancer. A patient may not need all of these tests, however, before a biopsy decision can be made. Such tests determine who is most likely to have a higher-grade tumor that may be treated and allow us to avoid biopsy in those who don't have cancer or have very low-grade cancer that doesn't need treatment. At UCSF, we have decreased biopsy rates by about 40% using such tests.
If you have had symptoms of urinary infection or prostatitis, your doctor may prescribe antibiotics prior to further testing to eliminate the possibility of an infection being responsible for an elevated PSA. The decision to investigate further with a prostate biopsy is based on a combination of factors, including results of the PSA, DRE and other tests, family history, age, race and other medical conditions you may have. A biopsy should be performed only after discussing the procedure's risks and benefits with your doctor.
In some circumstances, your doctor may order a repeat PSA or other tests to help determine whether a benign condition led to an elevated PSA. These tests may include:
- Free PSA (blood test)
- 4Kscore (blood test)
- Prostate Health Index, or PHI (blood test)
- PCA3 (urine test)
- SelectMDx (urine test)
- ExoDx (urine test)
- MyProstateRisk (urine test)
- Multiparametric MRI (imaging test)
An MRI exam, if available, of the prostate is very helpful, allowing for a more targeted biopsy.
Diagnosing prostate cancer
Making a formal diagnosis of prostate cancer requires a needle biopsy. The tissue samples obtained from the prostate are then examined by a pathologist in a laboratory in order to confirm the diagnosis.
Transrectal ultrasound (TRUS) guided biopsy – A TRUS uses sound waves produced by a small probe placed in the rectum to create an image of the prostate on a video screen. The transrectal ultrasound image can sometimes provide valuable information about whether the cancer has reached the edge of or broken through the prostate gland capsule. The TRUS also provides an estimate of prostate size.
Whether or not the image reveals suspicious areas, the prostate is systematically biopsied for signs of cancer. After numbing the area around the prostate with a local anesthetic, your doctor will use an instrument called a biopsy needle to remove a series of tissue samples. The samples are then sent to a laboratory for examination. A minimum of 12 samples and up to 20 should be removed from different areas of the prostate and especially from any locations that appeared suspicious on MRI or TRUS. The procedure takes 10 to 15 minutes and usually causes only mild discomfort and a little bleeding. An antibiotic is usually given before and after the procedure to reduce the risk of infection, though there will still be a low risk of infection (1%).
Sometimes, the first biopsy doesn't identify any cancer, even when the patient's symptoms or PSA test results strongly suggest cancer. Repeat biopsies may be required in such cases. A prostate MRI is more commonly used in this situation than before a first biopsy, as are the other blood and urine tests described above, and a new test called ConfirmMDx, which analyzes genes in the normal-appearing tissue from the first biopsy. Your doctor can discuss these optional tests with you.
| Previous (Should I be Screened?) |