Adjuvant intravesical therapy in intermediate-risk non-muscle-invasive bladder cancer

Objective To evaluate the impact of adjuvant therapy on oncological outcomes in patients with intermediate-risk non-muscle-invasive bladder cancer (NMIBC), as due to the poorly-defined and overlapping diagnostic criteria optimal decision-making remains challenging in these patients. Patients and Methods In this multicentre study, patients treated with transurethral resection of bladder tumour for Ta disease were retrospectively analysed. All patients with low- or high-risk NMIBC were excluded from the analysis. Associations between adjuvant therapy administration with recurrence-free survival (RFS) and progression-free survival (PFS) rates were assessed in Cox regression models. Results A total of 2206 patients with intermediate-risk NMIBC were included in the analysis. Among them, 1427 patients underwent adjuvant therapy, such as bacille Calmette-Guerin (n = 168), or chemotherapeutic agents, such as mitomycin C or epirubicin (n = 1259), in different regimens up to 1 year. The median (interquartile range) follow-up was 73.3 (38.4-106.9) months. The RFS at 1 and 5 years in patients treated with adjuvant therapy and those without were 72.6% vs 69.5% and 50.8% vs 41.3%, respectively. Adjuvant therapy was associated with better RFS (hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.70-0.89, P < 0.001), but not with PFS (P = 0.09). In the subgroup of patients aged <= 70 years with primary, single Ta Grade 2 <3 cm tumours (n = 328), adjuvant therapy was not associated with RFS (HR 0.71, 95% CI 0.50-1.02, P = 0.06). While in the subgroup of patients with at least one risk factor including patient age >70 years, tumour multiplicity, recurrent tumour and tumour size >= 3 cm (n = 1878), adjuvant intravesical therapy was associated with improved RFS (HR 0.78, 95% CI 0.68-0.88, P < 0.001). Conclusion In our study, patients with intermediate-risk NMIBC benefit from adjuvant intravesical therapy in terms of RFS. However, in patients without risk factors, adjuvant intravesical therapy did not result in a clear reduction in the recurrence rate.