How is Prostate Cancer Diagnosed?
All treatment begins with a pathologist's diagnosis.
Prostate cancer is often discovered during screening as a result of an elevated prostate specific antigen (PSA) blood test and or an abnormal digital rectal exam (DRE). When cancer is incidentally found it is often in an early stage causing little or no symptoms. Sometimes more advanced cancers are found due to the symptoms they cause. Regardless of how prostate cancer is suspected, a biopsy is the only way to make the diagnosis.
Medical history and physical exam
As part of any workup for suspected disease, your doctor will perform a complete physical exam. In particular, symptoms related to prostate cancer will be searched for, such as any urinary or sexual problems, and how long you have had them. Your doctor may also ask about bone pain, which could be a sign that the cancer might have spread to bones.
A physical exam is also important including a DRE. Your doctor will carefully examine the size, shape and contour of the prostate. Not all abnormalities in the way the prostate gland feels will be due to cancer. One disease in particular that is very common, benign prostatic hyperplasia (BPH) may be found. BPH can cause many of the same symptoms as prostate cancer.
PSA blood test
Prostate specific antigen (PSA) is a protein secreted by the prostate. It is elevated in 80% of prostate cancers but also can be seen due to benign causes. These include common conditions such as benign prostatic hyperplasia (BPH, prostate enlargement) and inflammation. An elevated PSA is a red flag and an indication to undergo further testing to determine the cause.
PSA results also factor into the staging of prostate cancer. It is also an important part of monitoring prostate cancer during and after treatment.
Transrectal ultrasound (TRUS)
TRUS is often the first imaging modality used to evaluate the prostate after a high PSA level is found during screening and/or an abnormal DRE. This involves using a small ultrasound probe to visualize the prostate. It is also used during a biopsy to direct the needles to the correct areas of the prostate for sampling.
New diagnostic techniques are available which can yield additional information and can help in the decision of whether to perform a tissue biopsy. The Prostate Health Index (PHI) test is a combination of three forms of the PSA protein. The results are used to provide a probability of cancer. The 4K score is a blood test measuring 4 different prostate related proteins that provides a percent risk score of having an aggressive prostate cancer. Another test is the Prostate Cancer Gene 3 test (PCA3) which is a gene based test carried out on urine. The higher the level, the more likely the chance cancer is present.
One of the newest and most promising techniques for further evaluating the prostate is the UroNav MR/Ultrasound Fusion Biopsy System. Fusion biopsy is a more effective method for detecting and diagnosing high risk and aggressive prostate cancers and results in less false negatives. MRI biopsy is likely to become an important tool in the evaluation of prostate cancer since the traditional random biopsy may miss tumor or in 30% of the time, underestimate the Gleason score of tumor.
A biopsy may be performed if the screening tests, DRE or imaging exams are abnormal. In this procedure, small cores of tissue are taken from each of the zones of the prostate, on both the right and left sides, in an attempt to sample the entire gland. This is done using the assistance of ultrasound and a needle placed through the wall of the rectum into the prostate.
If a biopsy is done, the samples are sent to the lab where a pathologist will evaluate the biopsy under a microscope and make a diagnosis. The most important feature to know about the cancer is the Gleason score. This is a grading system that a pathologist assigns to the tumor. A higher score suggest a more aggressive tumor. Other features that are assessed for include: the amount of tumor, the percentage of tumor in each biopsy sample, tumor length and whether tumor invades small nerves of the prostate. All of these will be recorded in the pathology report. Get a copy of your report.
Other important diagnoses that might be encountered are:
Atypical small acinar proliferation (ASAP) – This is an area that has microscopic finings equivocal for cancer, i.e. suggestive but not diagnostic. It is predictive of cancer and often an indication for repeat biopsy.
Prostatic intraepithelial neoplasia (PIN) – This is another finding that has microscopic features worrisome for cancer. It carries a 20% risk of cancer on repeat biopsy. Like ASAP, it warrants close follow up.
Your pathologist is an important member of your care team. Ask about the pathologist involved in your case. Request a copy of your pathology report. Understand the report. Ask questions.