Preoperative predictive factors of carcinoma in situ in the normal‐appearing mucosa in patients who underwent an initial transurethral resection for non‐muscle‐invasive bladder cancer under white light cystoscopy

BACKGROUND: Although few studies evaluated the significance of random biopsies under white light cystoscopy (WLC) in patients with non‐muscle‐invasive bladder cancer (NMIBC), the findings are controversial. AIM: This aim of this study was to evaluate what kind of preoperative covariates were useful as predictive factors in detecting carcinoma in situ (CIS) from normal‐appearing mucosa using random bladder biopsies under WLC. METHODS AND RESULTS: A total of 229 patients with NMIBC underwent initial TUR followed by random biopsies under WLC at Red Cross Takayama Hospital between 2007 and 2016. These patients underwent TUR with complete resection of intravesical visible tumors followed by random biopsies of normal‐appearing mucosa. In this study, random bladder biopsies of normal‐appearing urothelial mucosa, excluding abnormal mucosa, were carried out with a cold punch in the selected intravesical sites. The covariates included age, gender, the urine cytology result, presence of an abnormal mucosa, number of tumors, size of the largest tumors, configuration of the tumor, and tumor type. Abnormal mucosa was defined as reddish or mossy areas at the time of TUR under WLC. The primary endpoint was to determine what kind of preoperative covariates were useful as predictive factors in detecting CIS from normal‐appearing mucosa using random bladder biopsies under WLC. Finally, 212 patients were evaluated, and 67 patients (31.6%) were diagnosed with CIS from normal‐appearing mucosa. In univariate analysis, positive urine cytology, abnormal mucosa, and the number of tumors were significantly associated with concomitant CIS. On multivariate analysis, positive urine cytology and abnormal mucosa were significantly associated with CIS. CONCLUSION: The patients who were diagnosed with positive urine cytology or abnormal mucosa by WLC are ideal candidates for TUR followed by random biopsy of normal‐appearing mucosa.