Is restaging transurethral resection necessary in patients with non-muscle invasive bladder cancer and limited lamina propria invasion?

To evaluate the influence of lamina propria invasion type at initial transurethral resection (TUR) on restaging pathology. We reviewed prospectively maintained records of all patients with a high-grade pT1 nonmuscle invasive bladder cancer who underwent both initial and restaging TUR within 6 weeks at our center between 2001 and 2016. The pathology of second TUR specimens was analyzed with regard to the characteristics of lamina propria invasion found at initial resection. We included 198 patients, with a median age of 70 years (interquartile range: 63–79). Muscle was present in the initial TUR specimen in 107 patients (54%). Pathology restaging was pT0 in 73 patients (37%), pTis in 44 (22%), pTa in 27 (14%), pT1 in 50 (25%), and pT2 in 4 (2%). Eighty-seven patients (44%) had tumors with minimal lamina propria invasion at initial TUR: 53 specimens (27%) had focal invasion (few malignant cells in the lamina propria); 15 specimens (7.6%) had superficial invasion (invasion of the lamina propria to the level of the muscularis mucosae [T1a]); and 19 specimens (10%) had multifocal superficial invasion (multiple areas of T1a). Of the patients with minimal lamina propria invasion, residual disease was found in 54 patients (62%). However, none of those patients had T2 disease. A significant number of patients with T1 tumors have residual disease at restaging TUR as do patients with minimal lamina propria invasion. The extent of T1 invasion does not eliminate the need for repeat TUR. •Minimal lamina propria invasion does not reduce the risk of residual disease.•Residual disease can be found even if muscle was present at initial specimen.•The extent of T1 invasion does not eliminate the need for repeat TUR.