Inclusion of Additional Component to Prostate Cancer Score Improves Test Accuracy

Researchers show that incorporating a third component to a common diagnostic score better predicts time to disease recurrence

Prostate cancer aggressiveness and prognosis is currently predicted based on the Gleason score, which is the sum of two scores determined by the most prevalent and second-most prevalent patterns of cells seen in prostate cancer specimens. Now, researchers at Brigham and Women’s Hospital (BWH) have found that if a third, small area of highly aggressive cancer is seen on biopsy, it is associated with a worse prognosis for men with otherwise moderately aggressive disease. These findings are published in the October 3, 2007 edition of the Journal of the American Medical Association.”Currently, if a minor component of aggressive disease is found within a prostate cancer biopsy specimen, it is not uniformly included in the report of the Gleason score” said Abhijit Patel, MD, PhD, lead author of the study and physician in the department of Radiation Oncology at BWH. “However, this research indicates that because this minor component of aggressive disease affects prognosis, it can alter treatment decisions, and should always be reported if present.”A Gleason score is a system that classifies prostate cancer based on its microscopic appearance, and is used to help evaluate prognosis and guide therapy. The Gleason score ranges from 2 to 10 and is determined by a pathologist based upon the pattern of cells in the specimen from a radical prostatectomy or a biopsy. A score of 10 signifies the most aggressive cancer. The score is calculated by adding two scores, each between 1 and 5, from the primary and secondary patterns in the cancerous cells. A Gleason score of 7 represents moderately aggressive cancer, and is the most commonly assigned score.Dr. Patel and colleagues explored the relationship between the presence or absence of a tertiary highly aggressive cell pattern of grade 5 and the time to prostate-specific antigen (PSA) failure, or recurrence. For more than four years, researchers followed 2,370 men with localized or locally advanced prostate cancer who were treated with radical prostatectomy, radiation therapy or radiation therapy with six months of androgen suppression therapy.Researchers report:

• Men with a Gleason score of 7 and a highly aggressive tertiary grade of 5 had a shorter time to disease recurrence when compared to men with a Gleason score of 7 without a tertiary grade 5.
• Men with a Gleason score of 7 and tertiary grade 5 had an average of five years to recurrence compared with men who had a Gleason score of 7without tertiary grade 5, who experienced recurrence within an average of 6.7 years.
• Time to recurrence for men with a score of 7 and tertiary grade of 5 is comparable to men with a Gleason score between 8 and 10, which is highly aggressive cancer.

“There is no consensus about the optimal treatment for men with Gleason score 7 prostate cancer. However, this study suggests that if the biopsy specimens of such men show a minor component of highly aggressive, grade 5 cancer, more than radiation or surgery alone will be needed to reduce recurrence rates in the majority of these men,” Patel concluded.(Source: Journal of the American Medical Association : Brigham and Women’s Hospital : December 2007)