The DaBlaCa-13 Study: Short-term, Intensive Chemoresection Versus Standard Adjuvant Intravesical Instillations in Non-muscle-invasive Bladder Cancer-A Randomised Controlled Trial

Abstract

Background: Instillation therapy for non-muscle-invasive bladder cancer (NMIBC) reduces recurrences but is associated with side effects. Preoperative instillation of chemotherapy could potentially be associated with fewer side effects compared with adjuvant instillations and in some patients make tumour resection (transurethral resection of the bladder tumour [TURBT]) superfluous.

Objective: To investigate tumour response and adverse events related to short-term, intensive chemoresection with mitomycin C compared with adjuvant instillations in patients with recurrent NMIBC.

Design, setting, and participants: A randomised, controlled trial was conducted in two urological departments in Denmark from January 2018 to June 2019. In total, 120 participants with a history of Ta bladder tumours, low grade or high grade, were included upon recurrence.

Intervention: Intravesical mitomycin C (40 mg/40 ml) three times a week for 2 wk in the intervention group (59 patients) was compared with TURBT and six weekly adjuvant instillations in the control group (61 patients).

Outcome measurements and statistical analysis: Tumour response was evaluated in the intervention group by flexible cystoscopy after 4 wk. Side effects were prospectively registered in both groups using the National Cancer Institute's Common Terminology Criteria for Adverse Events. Groups were compared using χ² or Fisher's exact test.

Results and limitations: Complete tumour response was seen in 33 participants (57%) in the intervention group. Fewer adverse events were reported in the intervention group than in the control group. Two patients in each group ceased instillation treatment due to adverse events. The main limitation is the current lack of long-term follow-up.

Conclusions: Short-term, intensive chemoresection yields a tumour response of 57%. Hence, only half of those treated with chemoresection needed TURBT. The treatment was furthermore associated with fewer clinically significant side effects. Owing to small numbers, further investigations on Ta high-grade tumours are needed.

Patient summary: We compared a nonsurgical treatment with standard treatment in patients with superficial bladder tumours. We found it to be safe and able to avoid surgery in more than half of the patients.

Keywords: Chemoablation; Chemoresection; Intravesical chemotherapy; Mitomycin C; Non–muscle-invasive bladder cancer.