BERKELEY, CA (UroToday.com) - PSA screening has led to the over detection of small volume and perhaps indolent prostate cancer (CaP). In the online version of Cancer, Dr. Hamden and colleagues report a meta-analysis on whether patients with microfocal CaP on biopsy have adverse pathologic findings or any significant risk of PSA recurrence after undergoing radical prostatectomy (RP).

A total of 238 articles were carefully evaluated and in the final review 29 articles addressed the specific question of the correlation between small-volume cancer on biopsy and pathologic findings, biochemical or clinical progression, or mortality. Where possible, outcome data were pooled to estimate the overall risk associated with small-volume cancer at biopsy. A fixed-effect model was used if there was no evidence of heterogeneity at the significance level of P=.1. If heterogeneity was evident, then a random-effects model was used.

All the studies were retrospective. Studies varied in the maximum number of biopsy cores that were allowed to qualify for the definition of microfocal CaP and whether the maximum length of cancer and highest Gleason score were specified. The most common values adopted were a single positive core and a cutoff value of 3mm for the CaP length. Regarding the likelihood that no CaP would be found in the RP specimen, the occurrence rate was 0.8%. The overall estimate of the risk that patients with microfocal CaP would have extracapsular extension (ECE) at RP was 17.6%. The combined estimate for a positive surgical margin among men with microfocal CaP was 12%. The range of PSA recurrences among this population was 0-26%, with an estimated risk of 8.6%. Among watchful waiting studies, the number of patients was small, and a rising PSA was reported in 9 of 15 patients who had a microfocus of CaP, and 4% experienced clinical progression. Conversion to definitive therapy occurred in 30%.

The authors acknowledge several limitations to include marked variation in men diagnosed due to an elevated PSA (18.5-95%). Also, the proportion of patients excluded from the final analysis was up to 29%. Finally, no details about surgical expertise were included and may account for different outcomes. Despite these limitations, the overall suggestion is that a small volume of CaP in prostatic biopsies is not necessarily indicative of a good prognosis.

Harnden P, Naylor B, Shelley MD, Clements H, Coles B, Mason MD

Cancer, Volume 112, Issue 5, Pages 971 - 98 - Epub
doi: 10.1002/cncr.23277

PubMed Abstract
PMID: 18186496

Written by Christopher P. Evans, MD, a Contributing Editor with UroToday.

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