One of the tools used for the diagnosis and treatment of prostate cancer is the Gleason scoring system, which grades adenocarcinomas (malignant tumors) of the prostate based on the patterns of prostatic glands. Many studies have confirmed the prognostic significance of the Gleason score with respect to time to recurrence and death following therapy, according to background information in the article. The Gleason scoring system assigns a grade of 1 to 5 (higher grade being less differentiated) to the predominant pattern and to the second most prevalent pattern in the prostate specimen. The two grades are summed to arrive at a final score between 2 and 10. Although the Gleason scoring system does not incorporate a third pattern, the presence of more than two Gleason patterns in an individual tumor is widely recognized to occur and many pathologists use a tertiary (third) pattern.
Abhijit A. Patel, M.D., Ph.D., of Brigham and Women's Hospital and the Dana Farber Cancer Institute, Boston, and colleagues conducted a study to compare the prognostic significance of Gleason score 7 with tertiary grade 5 vs. other Gleason scores with respect to time to prostate-specific antigen (PSA) failure (an increase in the blood level of PSA after prostate cancer treatment with surgery or radiation). From 1989 to 2005, 2,370 men with various tumor grades and prostate cancer that had not spread to nearby lymph nodes or elsewhere in the body, underwent therapy with surgery or radiation therapy with or without hormonal therapy. Gleason scores were assigned to the prostate needle biopsy specimens.
The researchers found that men with Gleason score 7 and tertiary grade 5 disease had a significantly shorter time to PSA failure than men with 7 without tertiary grade 5 (median [midpoint] time, 5.0 vs. 6.7 years, respectively); or score of 6 or less (median time, 15.4 years). However, a significant difference was not observed when these men were compared with men with Gleason score 8 to10 disease (median time, 5.1 years).
"If these findings are validated by additional studies in other populations, they may affect the management of care for men with Gleason score 7 prostate cancer for which the currently practiced management standards include dose-escalated radiation therapy including prostate brachytherapy [radiation therapy where the radioactive source is placed inside the prostate] with or without supplemental radiation therapy, radiation therapy and short course androgen suppression therapy (AST) or radical prostatectomy. Specifically, given the time to recurrence, management options for men with Gleason score 7 who also have tertiary grade 5 disease could include treatments that are the current standards of care for men with Gleason 8 to 10 prostate cancer," the authors write.
"These standards of care based on the results of randomized trials include radiation therapy and short- or extended-course AST or radical prostatectomy with the expectation that further therapy may be needed postoperatively depending on the final pathology findings of the radical prostatectomy and postoperative PSA level."