Fox Chase Uses Innovative Transperineal Biopsy Technique for Detecting Prostate Cancer to Reduce the Chance of Biopsy-Related Complications
For some men who need a prostate biopsy to test for prostate cancer, Fox Chase Cancer Center offers an alternative approach that is safer, with significantly lower risks of infection, and potentially higher rate of tumor detection.
Most prostate biopsies are traditionally done through the rectum (transrectal), but there is the means to obtain prostate tissue samples through the perineum using an external entry point at the skin. In this modification of the standard transrectal approach, doctors take samples of the prostate tissue through needles directed through the perineum, the area of skin located between the rectum and the base of the scrotum.
David Y.T. Chen, MD, FACS
While the historic reported rate of infection from transrectal prostate biopsies has been around 1.5 percent, a recent study of transrectal biopsies performed throughout New York showed the chance of infection related complications increased from 2.6 to 3.5 percent between 2011 and 2014. For transperineal biopsies, in contrast, studies have shown that the infection rate is nearly zero. This reduction in risk of infection is particularly important, since rates of hard-to-fight infections are increasing.
As for its effectiveness in detecting cancer, researchers in multiple countries have shown that transperineal biopsies may be more effective in detecting cancer than transrectal biopsies, especially when the disease is located in the anterior (front) and ventral (lower front) regions of the prostate. A Norwegian study showed that 20-30 percent of transrectal biopsies do not detect cancer (a false-negative result), while subsequent transperineal biopsies are able to identify the tumor. Israeli researchers also have found increased cancer detection rates using the transperineal approach.
Fox Chase Cancer Center’s urologic oncology group has expertise in transperineal biopsy techniques and began offering this alternative procedure to patients earlier this year. They also use a specially designed device that limits the number of biopsy needle insertion points to two -- one for each side of the prostate -- which further reduces the chance of infection and other side effects. The transrectal biopsy typically involves 12 or more separate needle punctures from inside the rectum.
“We are always looking for ways to improve on our results, including with the diagnosis of prostate cancer using the standard transrectal biopsy procedure,” said David Y.T. Chen, a urologic oncologist at Fox Chase. “While it is a very effective and well-accepted approach, improvement in imaging technology through ultrasounds and MRIs has allowed us to ask whether there was another way that we may offer patients an advantage.”
What is the transrectal biopsy technique and how is the transperineal approach different?
A typical transrectal biopsy collects samples of prostate tissue by using a specialized biopsy instrument that is directed through the rectal wall into the prostate. Samples are taken from a uniform distribution throughout the prostate, which is located near the rectum and is commonly examined in a manual physical exam done by a doctor. The standard transrectal biopsy procedure is usually done in the doctor’s office with patient fully awake. Local anesthesia is injected around the prostate to numb the area prior to obtaining biopsies. To take the samples, the doctor places an ultrasound probe into the rectum, and the biopsy device is directed parallel to the probe and pierces through the rectum wall and into the prostate; each sample requires a new puncture.
For a transperineal biopsy, patients have the procedure in an operating room under a sedation level of anesthesia as an outpatient surgical procedure. The use of more than local anesthesia helps with patient comfort, and makes it easier for the patient to stay still during the procedure. An ultrasound probe is also utilized, inserted in the rectum to allow imaging of the prostate, and the Precisionpoint ™ guide enables biopsies to be taken from each side through only two primary skin puncture sites. This lets the doctor take a distribution of samples from throughout the prostate, including access to the anterior (front) and apical (top) regions of the prostate.
What are the advantages of a transperineal approach?
- Reduced risk of infection
- Reduced risk of procedure-related bleeding
- Increased chance for detecting cancers, particularly in the anterior of the prostate.
- A viable option for patients with anxiety about having a prostate biopsy procedure while fully awake, and who would prefer to be under a greater level of sedation or anesthesia during the biopsy.
What are the potential side effects of the two procedures?
Chen noted that although patients take antibiotics before transrectal biopsies to fight a potential infection, there are times when fecal bacteria can get into the bloodstream during the procedure and the body is not able to fight off the infection. The colon, which is a blood-vessel-rich organ, may have hemorrhoids or larger blood vessels in the puncture area, which could increase bleeding and infection risks. As the transrectal biopsy requires a separate puncture for each sample, it increases the risks for both problems.
In a transperineal procedure, very few blood vessels are in the region of the biopsy approach, so the chances of bleeding are reduced. The perineum can be effectively sterilized prior to any needle puncture, which is probably the basis for the much lower risk of infection reported for this approach.
Chen said doctors have begun looking for new ways to avoid infections for two reasons: infectious bacteria have been rapidly evolving resistance to many current antibiotics, and simply using stronger antibiotics to prevent infection can have potentially more side effects on patients and for the population in general.
“Both bleeding and infection risk are minimized when we use a transperineal approach,” he said. “While we may never be able to get to totally zero complications for this procedure, we expect the overall risks can be significantly lower with the transperineal approach.”
In addition, a study out of University of Cambridge, United Kingdom, published in the journal BJU International showed that transperineal biopsy detected more high-grade/high-stage tumors in patients with elevated prostate-specific antigen (PSA) levels and previous negative transrectal biopsies. These cancers also were found in the anterior (front) area of the prostate, which is more easily reached through the transperineal procedure.
The UK study compared the experience of patients undergoing transperineal versus patients with transrectal procedures and reported the following:
- Urinary retention requiring catheterization was slightly less common in the transperineal group (5.6 percent) than in the transrectal group (8.3 percent).
- Bleeding from the rectum was significantly lower in the transperineal group (1.1 percent) than in the transrectal group (14.2 percent).
How is a biopsy sample assessed?
Fox Chase pathologists have extensive experience in diagnosing prostate cancer, especially in early disease when benign tumors can be mistaken for cancer and vice versa.
After biopsy samples are taken, pathologists look for several different cancer-related cell patterns under a microscope. The Gleason Grading System uses the numbers 1 to 5 to classify the most common (primary) and next most common (secondary) cell types found in a tissue sample.
Together, the sum of these two numbers is the Gleason score, ranging from 1+1=2, to 5+5=10. This tells the physician how potentially aggressive the tumor cells may be, with a higher Gleason score indicating a more aggressive cancer. Doctors consider three factors -- the Gleason score, the PSA level and the volume (amount of cancerous tissue detected within the core of the biopsy) -- when evaluating a man with prostate cancer, in order to assess the potential aggressiveness of the cancer and assist in treatment options.
Who is a good candidate for transperineal biopsy?
- Patients who are on “active surveillance” for a slow-growing prostate cancer and are expected to need repeated biopsies
- Patients with high PSA scores whose previous standard transrectal biopsies did not detect cancer (which may be a false-negative)
- Patients suspected to possibly have tumors in the anterior or apical areas of the prostat
- Patients with anxiety who may benefit from a greater level of anesthesia and sedation during the prostate biopsy procedure
Have more questions about prostate biopsies?
If you have been told you need a prostate biopsy and want to know more about transperineal biopsies, call 888-369-2427.