January 10, 2000
Gleason Grade - the Pathology Report
Robert S. Gould, MD
When a patient receives a Pathology report after a needle biopsy of the prostate, he may see that it describes the tissue as either benign prostatic hyperplasia, chronic prostatitis, or nodular hyperplasia of the prostate any one of which is no cause for concern because these conditions will not cause any serious illness.
On occasion, however, the pathologist will describe PIN which stands for prostatic intraepithelial neoplasia. This is considered a pre-malignant lesion which turns out to be associated with cancer or turns into cancer in about half the cases. Repeat biopsy in 3-6 months is indicated when such a biopsy report occurs. Another approach is to biopsy the prostate from the perineal route rather than from a transrectal approach. With the perineal route, if transrectal ultrasonography is used to guide the biopsy, long segments of tissue can be obtained from below the capsule of the prostate where cancers often begin. This results in better sampling of the critical areas of the prostate than is possible with the transrectal approach.
Prostate cancer is a malignant growth originating in the cells of the prostate gland and is therefore described as adenocarcinoma (or glandular cancer). Whether or not the cancer is likely to grow slowly or very quickly depends on how closely the cells of the cancer resemble normal cells. Those that appear very much like normal glandular tissue with some cancer cells in the lining are termed well differentiated cancers. Those that appear very little like normal glands and more like sheets of packed cancer cells are termed poorly differentiated cancers. Those which form multiple small glandular spaces are in the middle and are called moderately well differentiated cancers.
Over the past fifteen years more detailed descriptions of the cancers have been given by pathologists and describe the tissue in terms of Gleason grade.
- Well differentiated cancers have a low Gleason grade (grade 2-4).
- Moderately well differentiated cancers have a moderate Gleason grade of 5 or 6.
- Poorly differentiated cancers have Gleason grades 8, 9, or 10
Well differentiated cancers tend to grow slowly and take a long time to become clinically significant. Their doubling time or the time it takes for the tumor to double in size is measured in terms of years. Moderately well differentiated cancers with a Gleason grade of 5 or 6 may become clinically significant if they occur in younger men below the age of 70-75. Over the age of 80, the patient is more likely to die of other causes than his prostate cancer.
Poorly differentiated cancers are described as Gleason grades 8, 9, or 10 and these tumors are very aggressive, have poor results with most treatments, and have doubling times which are measured in a matter of weeks or months. Grade 7 cancers act in between the moderate and high grade cancers and must be considered significant, but not incurable cancers.
Radical surgery results reported by Pound et al from Johns Hopkins are as follows:
- Ten year cancer survivals without evidence of disease for grade 2-4 cancers is 94%.
- Ten year cancer survivals without evidence of disease for grade 5 cancers is 91%.
- Ten year cancer survivals without evidence of disease for grade 6 cancers is 78%.
- Ten year cancer survivals without evidence of disease for grade 7 cancers is 46%.
- Ten year cancer survivals without evidence of disease for grade 8-10 cancers is 23%.
Most recently new forms of cryosurgery may offer improved results for patients with the higher grade cancers. Further information about prostate cancer including the importance of PSA levels in cancer survivals can be obtained by asking your health professional. To have your questions answered, make a request by email to: Robert S. Gould, M.D.
From the Division of Urology, U. Mass. Health Systems Hospitals/Marlborough, MA
And The Massachusetts Prostate Cancer Research Institute