Indenter study: Associations between prostate elasticity and lower urinary tract symptoms

Abstract

OBJECTIVE: To investigate the associations between prostate elasticity and lower urinary tract symptoms (LUTS). METHODS: From August 2009 to December 2009, 48 patients with no history of neoadjuvant therapy or previous prostate surgery who underwent robot-assisted radical prostatectomy were included in this study. A novel palpation system was used to measure the tissue elasticity of the prostate specimens. The elasticity of the prostate was defined as the mean elastic modulus (kilopascals [kPa]) of 21 sites from the posterior surface of prostate. All patients completed an International Prostate Symptoms Score questionnaire before surgery, and LUTS was defined as an International Prostate Symptoms Score total of ≥8. Significant voiding symptoms were identified by a score of ≥5 on the basis of patient responses to 4 questions (Q1, Q3, Q5, and Q6), and storage symptoms were identified by a score ≥4 on the basis of patient responses to 3 questions (Q2, Q4, and Q7). RESULTS: The median elastic modulus of the prostate was 20.8 kPa (interquartile range 15.6-22.9), and the LUTS incidences and voiding symptoms were significantly higher in patients with an elastic modulus >20 kPa. The multivariate logistic regression results indicated that a higher elastic modulus (as a continuous variable) was independently associated with voiding symptoms (odds ratio 1.18, P = .038) after controlling for age and prostate volume. However, the elastic modulus was not independently associated with LUTS or storage symptoms. CONCLUSION: Patients with greater prostate stiffness are more likely to develop LUTS. Specifically, prostate elasticity was independently associated with voiding symptoms.