Predicting the resected tissue weight from a digital rectal examination and total prostate specific antigen level before transurethral resection of the prostate

Abstract

ObjectiveTo determine the use of the prostate specific antigen (PSA) level and digital rectal examination (DRE) findings to estimate the resected tissue weight (RTW) before transurethral resection of the prostate (TURP).Patients and methodsWe retrospectively analysed 983 patients who underwent TURP between December 2006 and December 2012. The primary outcome was the RTW required for clinical improvement, and was not associated with re-intervention. Age, PSA level, body mass index (BMI) and DRE findings were correlated and modelled with the RTW. The DRE result was defined as DREa (small vs. large) or DREb (small vs. moderate vs. large) according to the surgeon’s report. Equations to calculate RTW were developed and tested using receiver operating characteristic (ROC) curve analyses.ResultsThere were significant correlations between PSA level (r = 0.4, P < 0.001) and RTW, whilst BMI and age showed weak correlations. The median (range) RTW was 45 (7–60) vs. 15 (6–60) g for small vs. large prostates (DREa) (P < 0.001), respectively. Similarly, the median (range) RTW was 11 (6–59) vs. 26.2 (6–60) vs. 42 (7–60) g in small vs. moderate vs. large prostates (DREb) (P < 0.001), respectively. Using PSA level and DREb (model 3) there was a significantly better ability to estimate RTW than using PSA and DREa (model 2) or PSA alone (model 1) based on ROC curve analyses. The equation developed by model 3 (RTW = 1.2 + (1.13 × PSA) + (DREb × 9.5)) had a sensitivity and specificity of 82% and 71% for estimating a RTW of >30 g, and 84% and 63% for estimating a RTW of >40 g, respectively.ConclusionsThe PSA level and DRE findings can be used to predict the RTW before TURP.

A systematic review of the accuracy of the digital rectal examination as a method of measuring prostate gland volume

“…One particular study was commonly referenced in the DRE literature but was not included here because it used measurements of specimens taken by transurethral resection of the prostate rather than the whole gland and combined the DRE findings with PSA to create a composite score before determining the accuracy. 17 The articles reported a wide variety of sample sizes (39-2199 patients) but represented a combined total of 7891 patients from countries all over the world and spread across the range of dates, suggesting that the topic has wide and current interest. The DRE was conducted by a range of health professionals depending on whether the study was a screening study (which might involve general practitioners or nurses) or urologists with a special interest in DRE and who were seeking ways to improve its accuracy.…”

“…One particular study was commonly referenced in the DRE literature but was not included here because it used measurements of specimens taken by transurethral resection of the prostate rather than the whole gland and combined the DRE findings with PSA to create a composite score before determining the accuracy. 17…”