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Prostate Cancer: Diagnosis

How is prostate cancer diagnosed?

If your healthcare provider thinks you might have prostate cancer, you will need certain exams and tests to be sure. Diagnosing prostate cancer starts with your healthcare provider asking you questions. He or she will ask you about your health history, your symptoms, risk factors, and family history of disease. Your healthcare provider will also give you a physical exam.

What is a biopsy?

A biopsy is the removal of small pieces of tissue to test. The small pieces of tissue are looked at with a microscope. A biopsy is used to confirm a diagnosis of cancer. A core needle biopsy is the most common way to look for prostate cancer.

What to expect during your biopsy

A core needle biopsy to check for prostate cancer is most often done by a urologist. This is a doctor who is a specialist in problems of the urinary or genital tract. The procedure takes about 10 minutes. It is often done in a healthcare provider’s office. During a prostate biopsy:

  • The area near your prostate is numbed with anesthetic. 

  • An ultrasound probe is put into your rectum. This uses sound waves to create images on a computer. It helps guide the healthcare provider as to where to take the small pieces of tissue from your prostate.

  • A thin, hollow needle is used to take the samples from the prostate through the wall of the rectum. The needle moves in and out very quickly. Because of this, you may not feel much discomfort.

  • About 12 samples are taken from different areas of the prostate. 

  • To prevent infection, you may be given an antibiotic medicine.

After the procedure, you might have:

  • Soreness in the area

  • Blood in your urine or semen

  • Bleeding from your rectum

Biopsy results

Illustration showing abnormal cells that still appear as rings in grade 1 or 2 of prostate cancer

Illustration showing abnormal cells that vary in size and shape with fewer rings in grade 3 of prostate cancer

  Illustration showing abnormal cells that vary even more in size and shape in grade 4 or 5 of prostate cancer

Grade 1 or 2

Seen under a microscope, grade 1 or 2 cells are abnormal, but still appear to be organized in rings. This may indicate a slow-growing cancer.

Grade 3

Grade 3 cells vary more in size and shape. Fewer rings are visible. These cancer cells may grow more rapidly or still be slow growing.

Grade 4 or 5

Grade 4 and 5 cells form irregular closely packed rings or don’t form rings at all. They vary even more in size and shape than lower-grade cells. These grades indicate a fast-growing cancer.

Once the biopsy is done, the tissue pieces are looked at by a pathologist. This is a doctor who is a specialist in looking at tissue samples in a lab with a microscope. It usually takes a few days to get the results of a biopsy.

Gleason score

If cancer cells are found, the cancer is assigned a grade by the pathologist. The grading system for prostate cancer is called the Gleason score.

This scale uses numbers 1 to 5 to show how much the tissue looks like or does not look like normal prostate tissue. A grade is given to each of 2 areas of the prostate that have the most cancer cells.

The grades are:

  • Grade 1. The tissue with cancer cells looks a lot like normal prostate tissue.

  • Grades 2 to 4. The tissue looks in between normal and very abnormal.

  • Grade 5. The tissue looks very abnormal.

The grades from the 2 areas are added together. That number is then the Gleason score. The score is between 2 and 10.

Gleason scores are:

  • Gleason score of 6 or less. This is low-grade cancer.

  • Gleason score of 7. This is medium-grade cancer.

  • Gleason scores of 8 to 10. This is high-grade cancer.

The higher the Gleason score, the more likely the cancer will grow and spread.

Grade Groups

Medical experts have also started to use a new way to grade prostate cancer, called Grade Groups. They realized that the Gleason score might not always be the best way to grade prostate cancer. For example, not all cancers with a Gleason score of 7 are the same. Cancers with more Grade 3 areas (3 + 4 = 7 Gleason score) are less likely to grow and spread than cancers with more Grade 4 areas (4 + 3 = 7 Gleason score). And Gleason score 8 cancers are less likely to grow and spread than cancers with a Gleason score of 9 or 10. The Grade Group system breaks up prostate cancers into 5 Grade Groups:

  • Grade Group 1 = Gleason 6 (or less)

  • Grade Group 2 = Gleason 3 + 4 = 7

  • Grade Group 3 = Gleason 4 + 3 = 7

  • Grade Group 4 = Gleason 8

  • Grade Group 5 = Gleason 9 or 10

If your biopsy report shows you have prostate cancer, it might show both the Gleason score and the Grade Group.

In some cases, a biopsy doesn't find any cancer when there is cancer. This is called a false negative. This might happen if the biopsy misses areas with cancer. Your healthcare provider may tell you to get another biopsy if he or she thinks the test results may be wrong.

Other results from a biopsy

A biopsy may include other results. A pathologist may report cells that are abnormal, but are not cancer. They may call these cells suspicious. Suspicious cells may be:

  • Prostatic intraepithelial neoplasia (PIN). This is abnormal growth, but it is not cancer. PINs may be low grade or high grade. Men with high-grade PIN have a 20% chance that cancer is somewhere else in the prostate.

  • Atypical small acinar proliferation (ASAP). ASAP is also called atypia. The cells may look like cancer, but there are very few of them. Like PIN, it is more likely cancer is also in the prostate.

  • Proliferative inflammatory atrophy. This means prostate cells that are smaller than normal, and there is inflammation. This may lead to high-grade PIN or prostate cancer.

If you have any of these, your healthcare provider may watch your prostate health more closely. He or she may also do a second biopsy.

Next steps

When your healthcare provider has the results of your biopsy, he or she will talk with you about next steps. This may include treatment options if cancer is found, repeating the biopsy at a later time, or regular checkups.

Talk with your urologist or other healthcare provider if you have problems after your biopsy. Make sure you understand the results and what follow up is needed.

Online Medical Reviewer: Alteri, Rick, MD
Online Medical Reviewer: Gersten, Todd, MD
Date Last Reviewed: 5/1/2017
© 2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.
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