How Is Prostate Cancer Biopsied?
A biopsy is a sample of tissue taken from the body that is analyzed further to detect certain conditions, including cancer. These samples are analyzed under a microscope, and in the case of cancer, can identify that cancerous cells are present, and potentially the aggressiveness or stage of the cancer. For prostate cancer, there are two main types of biopsies, core needle biopsy and lymph node biopsy. Based on initial prostate cancer screening tests such as the PSA test (prostate-specific antigen), DRE (digital rectal exam), or other imaging techniques like MRI or CT scans, your doctor may recommend a biopsy. The results of your biopsy will be able to definitively determine if you have prostate cancer.
Core needle biopsy with ultrasound guidance
A core needle biopsy is the biopsy used for prostate cancer detection. If your doctor suspects that you may have prostate cancer based on earlier detection methods, they may recommend you undergo a core needle biopsy. Core needle biopsies involve inserting thin, hollow needles into the prostate gland to collect tissue samples called cores. The needles can be inserted into the prostate through the wall of the rectum. This is called a transrectal core needle biopsy. The needles utilize a special spring-loaded technology to insert and remove the needle, with the tissue sample, in under a fraction of a second. During a transrectal core needle biopsy, you will be under local anesthesia and will feel a small jolt of discomfort, but typically no pain.
This process will be repeated roughly 10-12 times to collect the samples. These samples will be analyzed under a microscope to look for the presence of cancerous cells. Ultrasound guidance (called transrectal ultrasound) is used to guide the needles into different areas of the prostate. An ultrasound probe, also called a transducer, is inserted into the anus during the biopsy and gives off high frequency sound waves that will bounce off of the prostate and other local soft tissues and organs to create images in real time. This will allow for your urologist to accurately place the needles and remove cores from any suspicious areas of the prostate.
Typically, the entire procedure takes roughly 10 minutes and can be done in your doctor’s office or an outpatient clinic. You may need to take antibiotics before and after the procedure to reduce your risk of infection. You may also need to empty your bowels using an enema before the biopsy, as well as be tested for a urinary tract infection or asked to stop taking any medications or supplements that may increase bleeding. In addition to infection, other risks or side-effects of a core needle biopsy include pain or soreness around the biopsy site, and blood in the urine, rectum, or semen for several days to weeks. You will generally be able to return to normal activities within 24-48 hours.
The results of your biopsy may take 1-3 days or more, however, your provider should let you know when to expect information. If your doctor does not get back with you during the time frame provided, you can call them to ask for an update. Core needle biopsies also have the potential to deliver false-negative results. A false-negative result occurs when your biopsy indicates that you do not have cancer because none of the samples contain cancerous cells, but there are cancerous cells or tumors in a location of the prostate that happened to be missed by the 10-12 samples. This is rare, but can happen. If you receive a negative result and your doctor still has concerns that you may in fact have cancer, a repeat biopsy may be performed.1-4
Pelvic lymph node biopsy
Pelvic lymph node biopsies, also called lymph node dissection or lymphadenectomy if the lymph nodes are removed, are considered to be the most accurate means of detecting lymph node metastasizes in men who have localized prostate cancer.5 This means, a lymph node biopsy can detect when a case of prostate cancer is beginning to, or has already, spread to other locations in the body. Lymph nodes play an important role in our immune system, as well as circulate fluid, nutrients, and more throughout our entire body.
Cancerous cells can break off of a localized tumor in the prostate and infiltrate the pelvic lymph nodes, where they can then get into the lymph fluid. At this point, the cancerous cells begin to circulate around and can spread to other organs. This process is called metastasis. Once a cancer has metastasized, it can be harder to treat, which is why it is important to determine as early as possibly if a cancer is starting to spread.
During a lymph node biopsy, either an entire pelvic lymph node or a portion of a pelvic lymph node is removed from the body and analyzed in a similar way to the prostate tissue samples from the core needle biopsy.
Aiding treatment decisions
Lymph nodes can be removed during a scheduled radical prostatectomy to treat localized prostate cancer. In this instance, before the surgeon removes the prostate gland, they may remove a pelvic lymph node and have the sample frozen and analyzed on the spot before continuing with the operation. The reason for this is that radical prostatectomies (or the removal of the entire prostate gland) are often only effective for cases of prostate cancer that have not spread beyond the prostate gland. If the lymph node tissue shows signs of cancer, the will rarely be major benefit to a radical prostatectomy, and the individual having their prostate gland removed may experience inconvenient, quality of life-altering side-effects that can be completely avoided.
In addition to happening during surgery to stop an unnecessary procedure, a lymph node biopsy can also be completed on its own. This is rare, however, and typically happens when a man is choosing not to have a radical prostatectomy in favor of radiation or other non-surgical treatment options. In these cases, parts of a pelvic lymph node may be taken out using a laparoscopic approach or fine needle aspiration (FNA). In the laparoscopic approach, small incisions are made in the abdomen and tiny cameras and tools are inserted into the body to remove a small sample of tissue. FNA may be used if a lymph node (or multiple lymph nodes) appear large on a CT or MRI scan. Typically, CT images will be used to guide a hollow needle into the lower abdomen to take a small tissue sample from the lymph node in question. Both approaches have fast recovery times, leave small (if any) scars, and utilize anesthesia.1,3,6