Transurethral resection specimens of the bladder (TURB): outcome of invasive urothelial cancer involving muscle bundles indeterminate between muscularis mucosae and muscularis propria

Abstract

Background: It may be difficult to diagnose muscularis propria on TURB as thin muscle fibers on TURB may represent either muscularis propria destroyed or splayed by urothelial carcinoma or muscularis mucosae, which may be hyperplastic. Design: 95 invasive bladder cancers seen at our instituion with follow-up (mean 25.4 months) where the initial TUR pathologic stage was ambiguous (T1 vs. T2) were analyzed (73 men; 22 women; mean age 69.4 years). Results: Subsequent restaging TURB or definitive therapeutic procedures performed ≤ 3 months after the original TURB done in 58 cases revealed 22 (37.9%) patients with non-muscle invasive disease and 32 (55.2%) patients with ≥ pT2 disease. Staging in 4 cases remained ambiguous. 37 cases eventually developed ≥ pT2 disease in 2/22 (9.1%) cases with non-muscle invasive disease on initial restaging TURB, 2/4 (50.0%) of cases with uncertain stage disease, and 14/37 (37.8%) cases with no restaging TURB. Patients with a final stage of non-muscle invasive disease had a lower risk of progression (T4 or metastatic disease) vs. those with a final stage of ≥pT2 (p=0.003), uncertain stage (p=0.012), or no stage confirmation (p=0.043). Conclusions: This is the first study to evaluate follow-up when initial TURB is equivocal for muscularis propria invasion. Similar to an atypical prostate needle biopsy, urologists should be encouraged to perform restaging TURBs in cases of equivocal muscularis propria invasion. Although this may seem intuitive, 37/95 cases did not have repeat staging/therapeutic procedures done within 3 months of initial TURB; 37.8% of these patients eventually developed ≥ T2 disease.