Most CaP is diagnosed by PSA, not DRE and the American Cancer Society recommendations recently have made DRE an optional adjunct to PSA rather than mandatory. The investigators’ hypothesis was that DRE may be a more significant predictor of CaP in obese men due to the difficulty of the exam with greater adiposity and that in this setting a palpable tumor would be more meaningful.
Over 3,000 men were studied from two US and one Italian medical center. Body mass index (BMI) was classified as normal (<25kg m-2), overweight (25-29.9kg m-2), and obese (≤30kg -2). Overall they diagnosed CaP in 45-48% of men at the three institutions. The US patients were more commonly obese than the Italians. Obese men were less likely to be diagnosed with an abnormal DRE relative to normal-weight men and overweight men, and this was more pronounced at the US institutions. In multivariable analysis, adjusting for BMI as a continuous variable, an abnormal DRE was associated with nearly twice the odds of any CaP compared with normal DRE in all 3 cohorts. Stratification by BMI category revealed that overweight and obese men with an abnormal DRE at all medical centers had nearly 2- to 6-fold greater odds of positive biopsy compared with a normal DRE. Tests for trend of risk across BMI categories were significant as BMI increased; abnormal DRE became a stronger predictor for CaP in all individual and combined cohorts. An abnormal DRE meant the risk of having high-grade CaP was twice as great and was most pronounced in the obese cohort. In regression models that included DRE, obese men displayed significant improvements in AUC values by inclusion of DRE while normal weight men did not. This was similar for the detection of high-grade CaP.
Chu DI, De Nunzio C, Gerber L, Thomas JA 2nd, Calloway EE, Albisinni S, Senocak C, McKeever MG, Moreira DM, Tubaro A, Moul JW, Freedland SJ, Bañez LL
Prostate Cancer Prostatic Dis. 2011 Jul 5. Epub ahead of print.