A biopsy is done to diagnose prostate cancer and find out the grade of the cancer (Gleason score).
A transrectal biopsy is used to diagnose prostate cancer. A transrectal biopsy is the removal of tissue from the prostate by inserting a thin needle through the rectum and into the prostate. This procedure may be done using transrectal ultrasound or transrectal MRI to help guide where samples of tissue are taken from. A pathologist views the tissue under a microscope to look for cancer cells.
|Transrectal biopsy. An ultrasound probe is inserted into the rectum to show where the tumor is. Then a needle is inserted through the rectum into the prostate to remove tissue from the prostate.|
Sometimes a biopsy is done using a sample of tissue that was removed during a transurethral resection of the prostate (TURP) to treat benign prostatic hyperplasia.
If cancer is found, the pathologist will give the cancer a grade. The grade of the cancer describes how abnormal the cancer cells look under a microscope and how quickly the cancer is likely to grow and spread. The grade of the cancer is called the Gleason score.
To give the cancer a grade, the pathologist checks the prostate tissue samples to see how much the tumor tissue is like the normal prostate tissue and to find the two main cell patterns. The primary pattern describes the most common tissue pattern, and the secondary pattern describes the next most common pattern. Each pattern is given a grade from 3 to 5, with grade 3 looking the most like normal prostate tissue and grade 5 looking the most abnormal. The two grades are then added to get a Gleason score.
The Gleason score can range from 6 to 10. The higher the Gleason score, the more likely the cancer will grow and spread quickly. A Gleason score of 6 is a low-grade cancer; a score of 7 is a medium-grade cancer; and a score of 8, 9, or 10 is a high-grade cancer. For example, if the most common tissue pattern is grade 3 and the secondary pattern is grade 4, it means that most of the cancer is grade 3 and less of the cancer is grade 4. The grades are added for a Gleason score of 7, and it is a medium-grade cancer. The Gleason score may be written as 3+4=7, Gleason 7/10, or combined Gleason score of 7.