Transurethral endoscopic ultrasound to assess tumor stage in bladder cancer
Endoscopic ultrasound is a critical component of tumor staging in many luminal cancers. Its utility as a staging modality for bladder cancer has not yet been fully explored. Trans-urethral ultrasound (TUEUS) could overcome limitations of traditional staging modalities because it allows for delineation of local anatomy as well as assessment of depth of invasion into the bladder. The objective of this study is to evaluate the diagnostic accuracy of TUEUS in differentiating muscle invasive (MIBC) & non-muscle invasive bladder cancer (NMIBC) when compared to tumor pathology.
IRB approval and informed consent were obtained per institutional protocol. 14 patients with bladder cancer were evaluated with TUEUS prior to trans-urethral resection of bladder tumor (TURBT). A single surgeon examined 31 distinct bladder lesions by TUEUS. The surgeon's intraoperative assessment of depth of invasion as either MIBC or NMIBC was then correlated with final TURBT pathology to evaluate for accuracy. Sensitivity, specificity, negative and positive predictive values were calculated.
Two tumors were deemed to be MIBC on pathology and the remaining 29 were NMIBC. When distinguishing between MIBC & NMIBC, there was 100% sensitivity [CI 100%, 100%] & specificity was 97% [CI 90%, 100%]. The positive predictive value was 50% and the negative predictive value was 100%. Size and location of tumor did not significantly affect the outcomes. There were no adverse events.
Tumor-staging sensitivity and specificity was 100% and 97%, respectively. TUEUS had excellent negative predictive value of 100%. The low positive predictive value may have been due to a small number of MIBC tumors. Enrollment in our study is ongoing. In conclusion, this pilot study demonstrated TUEUS was a safe procedure and has a high concordance with pathologic stage. TUEUS may be a promising tool that warrants further investigation for the local staging of bladder cancers.