Introduction

So far few studies have investigated the predictors for identifying the presence of malignant lesions in random biopsies for the assessment of the therapeutic effect of BCG instillation against bladder carcinoma in situ (CIS) in patients with non-muscle invasive bladder cancer (NMIBC).

Methods

We retrospectively identified 144 patients who were initially diagnosed with bladder CIS with or without papillary lesions and treated with BCG therapy between 1995 and 2015 at our 2 institutions. Among them, 80 patients (55.6%) received random biopsies after BCG therapy in order to evaluate the therapeutic effect of the BCG therapy (RBx group) and 64 (44.4%) did not receive the random biopsies (no-RBx group). Velvet-like, reddish areas or irregular mucosa indistinguishable from inflammation were recognized as positive findings on cystoscopy 1 month after BCG therapy. We evaluated the association between parameters such as cytology results just after BCG therapy as well as the cystoscopic findings and malignant lesions on the final random biopsy specimens.

Results

Overall, median patient age was 70.5 years and the median follow-up period was 4.5 years. No significant differences in clinicopathological characteristics were observed between patients in the RBx group and those in the no-RBx group. The 5-year recurrence-free survival rate in the RBx group was 40.3±6.6%, which was not different from that in the no-RBx group (44.5± 8.3%, p=0.386). In the RBx group, 25% (20/80 patients) had malignant lesions on the final random biopsy specimens. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the cytology results just after completion of BCG therapy, the cystoscopic findings, and their combinations are shown in the Table below. Among the 27 patients who had negative cytology and cystoscopic findings, none had malignant lesions in the final random biopsy (NPV=100%).

Conclusions

The combination of negative cytology just after completion of BCG therapy and negative cystoscopic findings could eliminate unnecessary random biopsy after BCG therapy in bladder CIS patients.

Funding

none