Our Summary

Prostate cancer is often diagnosed via a method called MRI-targeted prostate biopsy. There are two ways to grade the severity of the detected cancer: using an aggregate Grade Group (gGG) that averages the severity across all biopsied areas, or the highest Grade Group (hGG) which only looks at the worst affected area. Previous research found that both methods are roughly equally accurate, but if they disagree, the gGG method is more likely to underestimate the severity, while the hGG method tends to overestimate it.

This study looked at a larger group of prostate cancer cases to compare the accuracy of these two grading methods. It found that when the gGG and hGG methods disagree, the gGG method is more accurate at predicting the severity of the cancer, especially for moderate severity cases (GG2 and GG3). The hGG method more often overestimated the severity in these cases.

Neither the level of prostate-specific antigen (a protein produced by the prostate which can indicate cancer) nor the PI-RADS score (a rating used to classify the likelihood of prostate cancer based on MRI images) were able to predict whether the gGG method would underestimate the severity of the disease.

In simpler terms, if a prostate biopsy shows different severity levels within the prostate, using an average severity measure (gGG) is more accurate than just looking at the worst affected area (hGG). This is especially true for cases where the cancer is of moderate severity.

FAQs

  1. What is MRI-targeted prostate biopsy and how is it used to diagnose prostate cancer?
  2. What are the two ways to grade the severity of the detected cancer in a prostate biopsy and how do they differ?
  3. Which grading method is more accurate when the gGG and hGG methods disagree about the severity of prostate cancer?

Doctor’s Tip

Patients should discuss with their doctor which grading method is being used for their prostate biopsy results. Understanding the severity of the cancer is important for making treatment decisions.

Suitable For

Patients who are typically recommended for a prostate biopsy include those with elevated prostate-specific antigen levels, abnormal digital rectal exam findings, or suspicious findings on imaging tests such as MRI. Additionally, patients with a family history of prostate cancer or other risk factors may also be recommended for a prostate biopsy. Ultimately, the decision to undergo a prostate biopsy should be made in consultation with a healthcare provider based on individual risk factors and symptoms.

Timeline

Before a prostate biopsy, a patient may experience symptoms such as difficulty urinating, frequent urination, blood in urine or semen, and pain in the back, hips, or pelvis. They may also undergo tests such as a digital rectal exam, a prostate-specific antigen (PSA) blood test, and a magnetic resonance imaging (MRI) scan to detect any abnormalities in the prostate.

During the prostate biopsy procedure, the patient will receive local anesthesia to numb the area before a needle is inserted into the prostate to remove small tissue samples for examination. The procedure may cause some discomfort or pain, but it is generally well-tolerated by patients.

After the biopsy, the patient may experience symptoms such as blood in urine or semen, pain or discomfort in the rectal area, and difficulty urinating. These symptoms typically resolve within a few days to a week.

Following the biopsy, the tissue samples will be examined under a microscope to determine if cancer is present and to assess the severity of the cancer using grading methods such as the Grade Group (gGG) or highest Grade Group (hGG). The patient will then work with their healthcare provider to develop a treatment plan based on the biopsy results.

What to Ask Your Doctor

Some questions a patient should ask their doctor about prostate biopsy include:

  1. Which grading method (gGG or hGG) will be used to determine the severity of my prostate cancer?
  2. How accurate is each grading method in predicting the severity of prostate cancer?
  3. What are the potential risks and benefits of each grading method?
  4. How will the results of the biopsy impact my treatment options?
  5. Can you explain how the level of prostate-specific antigen and PI-RADS score may affect the accuracy of the grading method?
  6. Are there any other factors that may influence the accuracy of the grading method in my specific case?
  7. What are the next steps after receiving the biopsy results?
  8. Are there any alternative methods of determining the severity of prostate cancer that I should consider?
  9. How often should I undergo follow-up testing or monitoring after the biopsy?
  10. Do you recommend seeking a second opinion on the biopsy results or treatment plan?

Reference

Authors: Ren J, Melamed J, Taneja SS, Wysock JS, Huang WC, Lepor H, Deng FM. Journal: Prostate. 2023 Mar;83(4):323-330. doi: 10.1002/pros.24464. Epub 2022 Dec 3. PMID: 36461793