Gleason Score of 3+4 is not equal to 4+3 in Lethal Prostate Cancer

USA (SANEPR.com) June 26, 2009 -- The Gleason scoring system is an important method of classifying prostate cancers based on the appearance of the prostate cancer cells under a microscope. Gleason patterns range from one to five, with higher Gleason patterns being associated with more aggressive disease. The Gleason score, which ranges from two to ten and is calculated by adding the primary (most prevalent) and secondary Gleason patterns, is an important prognostic tool for clinicians. Studies showing that short-term outcomes for prostate cancer differ according to Gleason scores have helped to guide clinical practice. Now, researchers at Brigham and Women’s Hospital (BWH) have shown that Gleason score is a strong predictor of prostate cancer mortality and that mortality rates differ among patients with a Gleason score of seven depending on whether Gleason pattern four is primary or secondary. This research is published in the May 11 issue of Journal of Clinical Oncology.

Researchers collected tissue samples from prostatectomies and biopsies from men who were diagnosed with prostate cancer between 1984 and 2004 and were enrolled in the Physicians’ Health Study and Health Professionals Follow-up Study. The samples were assigned primary and secondary Gleason patterns by study pathologists. Researchers found that within the group of men with Gleason scores of seven, men with primary and secondary patterns of 4 and 3 respectively had worse long-term outcomes compared to men with a primary pattern of 3 and secondary pattern of 4.

“Four plus three cancers were associated with a three-fold increase in lethal prostate cancer compared to three plus four cancers,” said Jennifer Rider Stark, Post-doctoral research fellow at BWH and the Harvard School of Public Health. “If we are lumping these cancers into one category of Gleason score 7, then we are missing important prognostic information.”

Lethal prostate cancer was defined by the development of bony metastases or prostate cancer death. Current clinical practice evaluates and treats men with three plus four cancer differently than a man with four plus three cancer, but until now there was no long-term mortality data to support this practice. Clinicians were making these decisions based primarily on surrogate outcomes such as prostate-specific antigen relapse.

“This study provides clinicians with further evidence that men who have Gleason scores of seven should be evaluated based on the predominant Gleason pattern,” Stark said.

This research was funded by grants from the National Cancer Institute.

About Brigham and Women's Hospital:-
Brigham and Women's Hospital (BWH) is a 777-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare, an integrated health care delivery network. In July of 2008, the hospital opened the Carl J. and Ruth Shapiro Cardiovascular Center, the most advanced center of its kind. BWH is committed to excellence in patient care with expertise in virtually every specialty of medicine and surgery. The BWH medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in quality improvement and patient safety initiatives and its dedication to educating and training the next generation of health care professionals. Through investigation and discovery conducted at its Biomedical Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human diseases, involving more than 860 physician-investigators and renowned biomedical scientists and faculty supported by more than $416 M in funding. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians' Health Studies and the Women's Health Initiative. For more information about BWH, please visit www.brighamandwomens.org.