Diagnosing Prostate Cancer

There are several tests to help doctors determine if you are at risk for prostate cancer. A biopsy can help confirm your diagnosis and also determine the extent (stage) of the disease.

Tests to diagnose prostate cancer

Digital rectal exam (DRE)1

Your doctor feels for any bumps or hard areas on the prostate by inserting a gloved finger into the rectum.

Prostate-specific antigen (PSA) test1

This is a blood test to detect levels of PSA in your blood. Higher levels can occur in men with prostate cancer.

Transrectal ultrasound (TRUS)1

Ultrasound waves are used to visualize your prostate.

Biopsy2

A biopsy is the only way to know for sure if prostate cancer is present. Your doctor removes small pieces of tissue with a needle. The tissue is then analyzed under a microscope to see if it contains cancer cells.

Grading prostate cancer: your Gleason score

If a biopsy finds cancer cells, the tissue sample is graded to predict how fast the cancer is likely to grow and spread. The “Gleason” grading system is used most often to grade prostate cancer.

Gleason grades: 5 distinct patterns

gleason-diagram

1 – Small, identical cells that are close together

2 – Cells in various shapes and sizes, loosely packed

3 – Increased cell size and shape irregularity; less distinction between cells

4 – Large, irregular fused cells

5 – Irregular fused cells that have invaded surrounding connective tissue cells

Source: Gleason DF. Histologic grading and clinical staging of prostatic carcinoma. In: Tannenbaum M, ed. Urologic Pathology: The Prostate. Philadelphia, PA: Lea & Febiger; 1997:171.

How the Gleason grading system works2

  • Samples from 2 areas of the prostate are graded 1 to 5
  • Pathologists look at each sample to score its respective pattern of cells
    • The most common pattern is the “primary grade” (eg, 3)
    • The second most common pattern is the “secondary grade”  (eg, 4)
  • The numbers are added together to get a Gleason score between 2 and 10
    • Primary grade 3 + secondary grade 4 = Gleason score 7

Staging prostate cancer

Test results and your Gleason score help determine if the cancer has spread outside the prostate. This is called staging.1 Staging helps your doctor choose the best treatment for you.1,2

Stage 1

Tumor is not felt during a digital rectal exam (DRE), but biopsy found cancer cells.

Stage 2

Tumor is felt during a digital rectal exam (DRE), but the cancer remains within the prostate gland.

Stage 3

Tumor has spread beyond the outer rim of prostate, but not to other organs.

Stage 4

Tumor has spread to tissues and structures next to the prostate.

References:
  1. Prostate cancer. American Cancer Society Web site. http://www.cancer.org/acs/groups/cid/documents/webcontent/003134-pdf.pdf. Accessed December 3, 2015.
  2. National Comprehensive Cancer Network<sup>®</sup>. NCCN Guidelines for Patients<sup>®</sup>: Prostate Cancer. Version 1.2015. National Comprehensive Cancer Network<sup>®</sup> Web site. http://www.nccn.org/patients/guidelines/prostate/index.html#1. Accessed September 14, 2015.