A 64-Year-Old Man with Elevated PSA Levels - Episode 4

Modalities for Prostate Cancer Diagnosis, Grading, and Staging

A focused discussion on the use of tools such as digital rectal exam, prostate biopsy, and MRI in prostate cancer diagnosis, staging, and grading.

Patient Case: A 64-Year-Old Man with Elevated PSA Levels

  • A 64-year-old-man underwent PSA testing during his annual physical with his primary care physician; PSA was 5.6 ng/mL and PSA density was 0.16.
  • He then saw a urologist, who ordered a multiparametric MRI; result was PI-RADS 4.
  • The patient was reluctant to undergo a prostate fusion biopsy, therefore the patient’s urologist recommended that he undergo exosome-based molecular testing to help determine risk of prostate cancer; his test score was 16.3.
  • The patient and urologist remained concerned about his PI-RADS 4 MRI score. The urologist also noted that the PSA density of 0.16 was slightly above the threshold of 0.1.
  • The patient elected to undergo TRUS-guided biopsy, which was negative for prostate cancer.

Judd W. Moul, MD, FACS: The number of patients undergoing a prostate biopsy in the United States I think approaches perhaps close to a million a year. It’s a very common procedure, and in general, if you just look at men in the United States who have a PSA [prostate-specific antigen] of less than 10 [ng/mL], and you look at the positive biopsy rate, depending on the study, it will range from 25% to perhaps as high as 40%, depending on the patient population. But in general, men who have a PSA from for example 2.5 to 10 [ng/mL], which is the most common zone we would see, about one-third of men would be expected to have prostate cancer diagnosed on a prostate biopsy.

In a gentleman who is diagnosed with prostate cancer, there is information from the biopsy that is critically important. One piece of information is the Gleason grade and Gleason score. In practical terms, the lowest Gleason score would be a 6, and the highest Gleason score would be a 10. Recently, we have switched this to what is called a grade grouping system, with Grade Group 1 representing Gleason 6; Grade Group 2 representing Gleason 3+4 = 7; Grade Group 3 representing Gleason 4+3 = 7; Grade Group 4 representing Gleason 4+4 = 8; and Grade Group 5 being Gleason 9 or Gleason 10.

The staging of prostate cancer is kind of interesting. If we use the traditional staging that is endorsed by something called the American Joint Commission for Cancer, or AJCC, the AJCC still considers the findings on the digital rectal exam to be the key factors determining the stage. So, stage T1c would be a prostate cancer that is found on a needle biopsy or an MRI, but in a situation where the digital rectal exam is negative. This case that we presented today, we assume that his rectal exam was negative. It’s not stated explicitly, but let’s assume his rectal exam is negative. He did not have prostate cancer, but let’s just say he did have prostate cancer. It would be stage T1c because it was not palpable on a rectal exam. Had he been palpable on a rectal exam, or had he had a tumor that was feelable on rectal exam, then he would have been either a stage T2a if it was unilateral, or T2b if it was bilateral. The controversy is that MRI has gotten more accurate, and the tendency would want to be to use the MRI information to help create the stage. But technically in 2022, if we still follow the letter of the law for the AJCC, we’re not taking into account the MRI information specifically in assigning the T stage.

Transcript edited for clarity.