Introduction:

Prior studies demonstrate that blue light cystoscopy (BLC) is associated with improved detection of both initial and recurrent cancers in non-muscle invasive bladder cancer (NMIBC) patients when compared to white light cystoscopy (WLC). However, the utility of BLC for surveillance in patients receiving Bacillus Calmette-Guerin (BCG) treatments is not well understood. If these patients are found to have tumor recurrence within 6 months of receiving appropriate BCG treatment, they may be classified as BCG unresponsive and therefore are offered second-line intravesical treatments, radical cystectomy, or the opportunity to enroll in clinical trials rather than additional BCG. Current guidelines do not provide recommendations on the use of BLC for surveillance cystoscopy, nor at the time of enrollment in clinical trials. Our objective was to determine if BLC improves recurrence detection in NMIBC patients undergoing BCG treatment. 

Methods:

Using the prospectively collected, multi-institutional Cysview registry we identified NMIBC patients (2014-2019) who received BCG treatment within the last 210 days prior to BLC. Our primary outcome was high-grade recurrence and whether lesions were detected on WLC, BLC, or both. To demonstrate the utility of BLC, we calculated the percentage of cystoscopies with recurrence that would have been missed with WLC alone. We also calculated a false positive rate which was the proportion of cystoscopies with biopsies of only BLC suspicious lesions, but ultimately had benign pathology. 

Results:

From 1702 unique BLC procedures, we identified 258 cystoscopy procedures with BCG treatment within 210 days prior to BLC. There were 6 patients with multiple cystoscopy procedures that met inclusion criteria. The overall recurrence rate was 46.5% (n=120) with detailed pathology results listed in Table 1. If only WLC had been used, 13% (n=16) of recurrences would have been missed because 10% (n=16/154) of cystoscopies with a normal WLC had high grade recurrence identified with BLC (Table 1). The same data can be interpreted as a “6 month complete-response rate” after BCG of 60.0% (n=154/258) if only WLC were used for surveillance vs. 53.5% (n=138/258) when BLC surveillance was added. Among the 16 patients with recurrence missed with WLC and identified with BLC, 88% (n=14) had CIS (Table 2). The false positive biopsy rate for BLC was 4% (n=11/258). Intravesical chemotherapy was administered in 10.5% (n=27) of the cystoscopy procedures.

Conclusion:

BLC identified patients with recurrences after recent BCG treatment that would have been missed with WLC alone. Providers should consider using BLC for surveillance of high-risk NMIBC patients undergoing BCG as it could change clinical management by identifying patients who are BCG unresponsive and eligible for alternative therapy and clinical trials. Future research is warranted to better clarify how BLC should be used both for entry into clinical trials and for surveillance while on trials, in order to maintain consistency of patient outcomes within a given trial and to allow for comparison of response rates across different trials.

Funding: N/A