The Necessity of Transrectal Prostate Biopsy in Advanced Prostate Cancer: the Dependence of Sensitivity, Specificity and Positive Predictive Value on Serum PSA Level

Oh, Jae Sang; Yoon, Duck Ki

Abstract

PURPOSE: Transrectal prostate biopsy(TR biopsy) is a definitive diagnostic procedure which is performed on patients who have DRE abnormalities or high PSA. However, TR biopsy can cause major complications such as urosepsis. In addition, there is no curative treatment for advanced prostate cancer(CaP). In this study, we evaluated the sensitivity and specificity of cancer detection by serum PSA level in CaP patients and assessed whether TR biopsy could be omitted in advanced CaP patients.
MATERIALS AND METHODS
Three hundred patients who underwent TR biopsy due to high PSA or DRE abnormalities were included. The patients who had either pyuria, acute urinary retention, or history of indwelling catheterization were excluded. Through review of the medical records, we assessed the sensitivity, specificity and positive predictive value of cancer detection per 5ng/ml increase of PSA level. Cancer advance was assessed through radical prostatectomy and radiologic findings.
RESULTS
Ninety-six patients had CaP and mean PSA was 124.0ng/ml. Among the 30 patients with tPSA above 55ng/ml, 29 had CaP and all these patients had advanced CaP in bone scan, MRI, CT and pathology of radical prostatectomy specimen. For PSA above 55ng/ml, sensitivity, specificity and positive predictive values were 30.2%, 99.5% and 96.7%, respectively.
CONCLUSIONS
This study shows that PSA above 55ng/mL was 96.7% accurate in predicting the presence of CaP and that all the detected cancers were advanced or metastatic ones. As TR biopsy can be an invasive procedure in debilitated patients, it can be omitted in patients aged 75 or older with PSA above 55ng/mL, especially in case of positive bone scan findings.