Preoperative Pyuria as a Predictor of False-Positive Rates in the Photodynamic Diagnosis of Nonmuscle-Invasive...

Although photodynamic diagnosis (PDD) using 5-aminolevulinic acid (ALA) is a highly a sensitive and excellent method for detecting nonmuscle-invasive bladder cancer, false-positive rates should not be overlooked. One of the factors causing false-positive results is inflammation. Currently, the relationship between pyuria and PDD accuracy remains unclear. Therefore, this study aimed to clarify the influence of preoperative pyuria on the diagnostic accuracy of PDD.

This study retrospectively analyzed 101 patients who underwent PDD-assisted transurethral resection of bladder tumors at Kochi Medical School Hospital between January 2018 and December 2020. After dividing the patients into two groups according to the presence or absence of preoperative pyuria, the diagnostic accuracy of each group was analyzed.

A total of 616 specimens from 101 patients were analyzed, among which 460 specimens from 75 patients belonged to the no pyuria group and 156 specimens from 26 patients belonged to the pyuria group. The sensitivity, specificity, positive predictive value, and negative predictive value of PDD were 90.2%, 64.1%, 38.6%, and 96.3% for the no pyuria group and 92.9%, 45.6%, 38.6%, and 94.5% for the pyuria group, respectively. The pyuria group had a lower specificity than did the no pyuria group, indicating a significantly higher false positive rate in the former.

Our findings suggest that the presence of preoperative pyuria did not affect the ability of PDD to detect cancer but may increase its false-positive rate and that preoperative pyuria is a useful predictor of false-positive PDD rates.