Original Article Importance of prostate volume in the stratification of patients with intermediate-risk prostate cancer Marco Moschini, 1,2 * Giorgio Gandaglia, 1 * Nazareno Suardi, 1 Nicola Fossati, 1 Vito Cucchiara, 1 Rocco Damiano, 2 Francesco Cantiello, 2 Shahrokh F Shariat, 3 Francesco Montorsi 1 and Alberto Briganti 1 1 Unit of Urology/Division of Oncology, IRCCS Ospedale San Raffaele, Urological Research Institute, Milan, Italy, 2 Research Doctorate Program in Urology, Magna Graecia University, Catanzaro, Italy, 3 Department of Urology, Medical University of Vienna and General Hospital, Vienna, Austria Abbreviations & Acronyms AUC = area under the curve BCR = biochemical recurrence BMI = body mass index CI = confidence interval HR = hazard ratio IQR = interquartile range PCa = prostate cancer PLND = bilateral pelvic lymph node dissection PSA = prostate-specific antigen PV = prostate volume RP = radical prostatectomy Correspondence: Alberto Briganti M.D., Department of Urology, Vita-Salute San Raffaele University, Via Olgettina 60, 20132 Milan, Italy. Email: briganti.alberto@hsr.it *These authors contributed equally to this work. Received 7 November 2014; accepted 29 January 2015. Objectives: To evaluate the role of prostate volume assessed at final pathology in the risk of biochemical recurrence in patients with clinically localized prostate cancer treated with radical prostatectomy. Methods: Overall, 5637 patients treated with radical prostatectomy between January 1993 and August 2013 were identified. Multivariable Cox regression analyses tested the as- sociation between prostate volume and biochemical recurrence in the overall population and after stratifying patients according to the D’Amico risk groups. Results: Mean (median) prostate volume was 50.61 mL (46 mL). When patients were strat- ified according to D’Amico risk groups, mean (median) prostate volume was 51.7 mL (48 mL), 49.8 mL (45 mL) and 50.6 mL (46 mL) in low-, intermediate-, and high-risk prostate cancer, re- spectively (P = 0.04). Overall, the 5-year biochemical recurrence-free survival rate was 87.9%. In multivariable Cox regression analyses, prostate volume was associated with a lower risk of biochemical recurrence (hazard ratio 0.99, 95% confidence interval 0.99–1.00), after account- ing for disease characteristics. However, when patients were stratified according to D’Amico risk groups, prostate volume represented an independent predictor of biochemical recur- rence only in individuals with intermediate-risk disease (hazard ratio 0.99, 95% confidence in- terval 0.99–1.00). Conversely, prostate volume was not associated with the risk of experiencing biochemical recurrence in patients with low- and high-risk disease. Conclusions: Smaller prostates are associated with increased risk of biochemical recur- rence after surgery only in men with intermediate-risk disease. In this category, the preoper- ative assessment of prostate volume might be helpful in order to identify patients at higher risk of biochemical recurrence after surgery. Additionally, prostate volume might be used to individualize follow-up schedules after radical prostatectomy. Key words: biochemical recurrence, prostate cancer, prostate volume, radical prostatec- tomy, risk groups. Introduction PCa represents the most commonly diagnosed malignancy in Western countries. The number of men diagnosed with PCa in the year 2014 was approximately 233 000 in the USA alone. 1 RP is one of the most frequently used treatment approaches in patients affected by clinically localized PCa. 2 Several preoperative models have been developed to identify patients at higher risk of recur- rence after primary treatment. The majority of these tools are based on clinical parameters, such as biopsy Gleason score, preoperative PSA and clinical stage. 3–5 However, these models have been shown to achieve a relatively low accuracy in the prediction of disease recurrence after sur- gery. 6 This is particularly true in patients with intermediate-risk disease, which still represents a heterogeneous category. 7,8 In this context, PV has been proposed as a predictor of adverse dis- ease characteristics and disease recurrence after primary treatment. 9–12 However, discrepant find- ings have been reported, where some studies failed to show a significant association between this parameter and the risk of recurrence. 13,14 Of note, currently available investigations are mainly limited by the inclusion of relatively small historic cohorts. 10,14 Observations obtained in this set- ting might not be generalizable to contemporary PCa patients because of several changes in the © 2015 The Japanese Urological Association 1 International Journal of Urology (2015) doi: 10.1111/iju.12748