The Risk of Upstaged Disease Increases with Body Mass Index in Low-Risk Prostate Cancer Patients Eligible for Active Surveillance

BackgroundObese patients have a greater risk of adverse pathologic features and biochemical recurrence after radical prostatectomy (RP). The impact of body mass index (BMI) on the risk of reclassification and deferred treatment in active surveillance (AS) programs has not been thoroughly assessed.ObjectiveTo evaluate the impact of BMI on the risk of reclassification for AS eligibility.Design, setting, and participantsWe assessed 230 men who underwent an immediate RP and were eligible for AS according to the following criteria: prostate-specific antigen (PSA) ≤10 ng/ml, clinical stage T1c, Gleason score ≤6, fewer than three positive cores, extent of cancer in any core <50%, and life expectancy >10 yr.InterventionAll patients underwent a standardised 21-core biopsy and RP at our department between January 2001 and December 2010.MeasurementsReclassification was defined as upstaged disease (pathologic stage >pT2) and/or upgraded disease (Gleason score ≥7; primary Gleason pattern 4) in RP specimens. PSA outcomes were also recorded.Results and limitationsMean BMI was 26.4 kg/m2, and 13% of patients were obese (BMI >30). Mean BMI was the only preoperative factor significantly associated with the risk of upstaged disease. In multivariate analysis, BMI >30 remained an independent predictive factor for upstaged disease (p = 0.003; odds ratio: 4.2). The risk of upgraded disease (primary Gleason pattern 4) was significantly decreased 4.5-fold in large prostate glands (>50 ml; p = 0.008). The biochemical recurrence-free survival curves were not significantly different between men who were or were not overweight (p = 0.950).ConclusionsObese men are at higher risk of upstaged disease, with a proportion of 30% of pT3 disease in RP specimens. BMI should be taken into account for inclusion of low-risk prostate cancer patients in AS programs, and our results may help urologists better inform their obese patients eligible for AS about this risk of reclassification and improve treatment decision making.