Prostate cancer volume estimations based on transrectal ultrasonography-guided biopsy in order to predict clinically significant prostate cancer

Abstract

Introduction: Tumor diameter is a reliable parameter to estimate tumor volume in solid organ cancers; its use in prostate cancer is controversial since it exhibits a more irregular pattern of growth. This study aimed to examine the association between the tumor volume estimations based on transrectal ultrasound (TRUS) guided biopsy results and the tumor volume measured on the pathological specimen.

Materials and methods: A total of 237 patients who underwent radical retropubic prostatectomy (RRP) were included in this retrospective study. The differences and correlations between cancer volume estimations based on TRUS guided biopsy findings and cancer volume estimations based on post-prostatectomy pathology specimens were examined. In addition, diagnostic value of TRUS guided biopsy-based volume estimations in order to predict clinically significant cancer (>0.5 cc) were calculated.

Results: The mean cancer volume estimated using TRUS biopsy results was lower (5.5±6.5 cc) than the mean cancer volume calculated using prostatectomy specimens (6.4±7.6 cc) (p<0.041).TRUS guided biopsy examination resulted in 5 false positive and 15 false negative cases. There was a significant but weak correlation between the two parameters (r=0.62, p<0.001). The sensitivity and specificity of TRUS guided biopsy in predicting the presence of clinically significant cancer was 93.4% (95% CI, 89.1-96.1) and 50.0% (95% CI, 20.1-79.9), respectively.

Conclusions: TRUS guided biopsy-derived estimations seem to have a limited value to predict pathologically established tumor volume. Further studies are warranted to identify additional methods that may more accurately predict actual pathological characteristics and prognosis of prostate cancer.

Figure 1. ROC curve for predicting clinically significant cancer, based on TRUS guided biopsy estimation.