Detrusor muscle in the initial TURBT specimen and recurrence rate at first check cystoscopy in non-muscle invasive bladder cancer

Introduction
The presence of detrusor muscle (DM) is an essential component in “complete” transurethral resection of bladder tumour (TURBT) specimen. This study analyses patients who were subjected to a “complete” first TURBT to determine the presence/absence of DM in the specimen.  

Methodology
Newly diagnosed non-muscle invasive bladder cancer (NMIBC) from 1-April-2007 to 31-March-2017(10-years) were retrospectively analysed at National Hospital of Sri Lanka. All TURBTs performed at initial diagnosis were analysed to determine the presence of DM in the specimen, the recurrence rate at first check cystoscopy (FCC) at 3 months and the association with surgeon's experience.

Results
Of 181 TURBT, 99(54.7%) were done by Consultant Urological Surgeon (CUS) and 82(45.3%) by senior registrars (SR). The overall DM positivity rate was 59.7% (n= 108/181), for CUS: 63.6% (n=63/99) and SRs 54.9% (n=45/82) (p=0.232); for pTa tumours:-CUS: 46.5%vs.SRs:50 %( p=0.751) and for pT1 tumours:-CUS: 76.8%vs.SRs:59.5 %( p=0.067). Analysis of those who were followed up (145/181, 80.1%) showed a positive recurrence at FCC in 27.1 %( 23/85) and 30.0 %( 18/60) when DM was present and absent in the first TURBT specimen respectively (OR=0.87(95%-CI: 0.41-1.8, p=0.7).  

Conclusion
Clinically, DM positivity rate has prognostic significance only in the pT1 category of NMIBC. For pT1 tumours, the positive DM rates for the CUS and SRs were 76.8% and 59.5% respectively. The indifference in the recurrence rate may be due to the considerable proportion of lost to follow up in our study. Nevertheless, measures should be taken to enhance the DM positivity rates among urologists to achieve accurate staging and better prognosis.