A small prostate could indicate high-grade prostate cancer
MedWire News: US study results show that prostate cancer patients with small prostate volumes are more likely to have high-grade disease at final pathology than patients with larger prostates.
"A relationship between prostate size and disease grade offers the opportunity to predict the final pathologic grade based on clinical parameters," say Daniel Barocas, from Vanderbilt University Medical Center in Nashville, Tennessee, and colleagues.
They add that this predictive ability could have implications for the management of prostate cancer including selecting suitable patients for active surveillance and planning radiotherapy.
Barocas and team used data from 2880 radical prostatectomy patients treated at their institute between 2000 and 2008 to characterize the relationship between prostate size and final pathologic outcome, having been alerted to the possibility by the results of the Prostate Cancer Prevention Trial.
Older age (70 years and above), higher prostate-specific antigen level (greater than 10 ng/ml), and later year of surgery (2006-2008) were all significantly associated with having a large gland size (52, 48, and 48 g, respectively).
The median prostate weight in the cohort was 45 g, and, overall, 51.5% of patients had high-grade prostate cancer (Gleason score 7 or greater) in their final pathology specimens. The probability of having high-grade disease decreased by approximately 15% across the lowest (less than 20 g) versus highest (100 g or above) prostate sizes, from 60% to 45%.
Multivariate analysis, adjusted for variables including age, race, prostate-specific antigen level, clinical stage, and Gleason score, showed that for every 2 g increment in prostate weight, the risk for high-grade disease reduced by 6%, report Barocas et al.
The predictive ability of the multivariable model was improved when prostate size was included, note the researchers, with an area under the receiver operating characteristics curve of 0.82 versus 0.80 when it was excluded.
Finally, smaller prostates (approximately 19 g) were also associated with a significant chance of having other adverse pathologic features such as positive surgical margins, extraprostatic extension of disease, and a Gleason score of 7.
The research team concludes that one of the main benefits of being able to predict pathological grade would be the ability to predict indolent disease.
This is "a critical mission of urologists to spare men from overtreatment," they conclude in the Journal of Urology.
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By Sarah Guy