Older Age And Time To Last Biopsy Are Associated With Rise In Gleason Score For Men On Active Surveillance For Low Risk Prostate Cancer

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Clinical Trials / Drug Trials
Article Date: 02 Jun 2008 - 4:00 PDT

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ORLANDO, FL (UroToday.com) - Contemporary active surveillance (AS) series for men with low risk prostate cancer describe a significant rate of Gleason upgrading on repeat prostate biopsy. Increasing Gleason grade is an important driver of secondary treatment for men on AS. A group from UCSF sought to determine the predictors of histologic grade change for men undergoing repeat prostate biopsy while on AS for low risk prostate cancer.

Men diagnosed with prostate cancer and electing AS as initial management were identified from the UCSF institutional database. Selection criteria for AS included: PSA<10ng/ml, biopsy Gleason score <6 with no pattern 4 or 5, cancer involvement of <33% of biopsy cores and clinical stage T1/T2a. Patients were followed with PSA measurement and DRE every 3-4 months and repeat prostate biopsy every 12-24 months. Only men with at least two prostate biopsies were included in the analysis. The primary outcome of the study was increase in Gleason score on repeat prostate biopsy. The association between pre-determined predictors and the primary outcome was analyzed by multivariate analysis using logistic regression modeling.

Out of 180 men with at least 2 prostate biopsies, 70 (39%) were found to have higher Gleason grade on surveillance biopsy. Mean patient age at diagnosis was 62.5 and median PSA was 5.5 ng/ml. Median follow-up for the entire cohort was 35 months (range 6-192).

On multivariate analysis both patient age and time to last biopsy were significantly associated with increase in Gleason score. Men aged 63 years or older were twice as likely to be upgraded when compared to men younger than 63 years of age (OR= 2.3, 95% CI 1.1-4.7). Men whose last biopsy was more than 2 years after diagnosis were 3 times as likely to be upgraded compared to men whose last biopsy was within 1 year of diagnosis (OR=3.4, 95% CI 1.5-8.2). There was no association between baseline PSA, PSA density, clinical stage, PSA velocity, or absolute number of biopsies and risk of histologic upgrading.

They conclude that older men on active surveillance are at a higher risk for increase in tumor grade on follow up biopsy. Longer time to repeat biopsy as opposed to greater number of biopsies is also associated with higher risk of grade change. These data suggest that changes in Gleason score with time may represent true grade or tumor volume progression more than simply sampling error. This also suggests that the biopsy interval may have to be shorter than 2 years particularly in older men.

Presented by Marc A Dall'Era, Badrinath R Konety, Maxwell V Meng, Katsuto Shinohara, Nannette Perez, Janet E Cowan, Peter R Carroll at the Annual Meeting of the American Urological Association (AUA) - May 17 - 22, 2008. Orange County Convention Center - Orlando, Florida, USA.

Reported by UroToday.com Contributing Editor Christopher P. Evans, MD, FACS

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