Intravesical Radiofrequency-Induced Chemohyperthermia for Carcinoma in Situ of the Urinary Bladder: A Retrospective Multicentre Study

Objective: To examine the effect of intravesical radiofrequency-induced chemohyperthermia (RF-CHT) in carcinoma in-situ (CIS) patients overall and split according to previously received therapy. Methods: CIS patients that underwent an induction and maintenance phase of≥6 RF-CHT instillations, and had either pathology or cystoscopy plus cytology available at 6 months of follow-up were retrospectively included. Complete response (CR), recurrences, cystectomy-free rate, overall survival (OS), and adverse events were evaluated. Analysis was performed for overall, bacillus Calmette-Guerin (BCG)-unresponsive, other BCG-treated, and treatment naive patients. Results: Patients (n = 150) had a mean of 17.5, 9.2, or 0 previous BCG instillations in the BCG-unresponsive (n = 50), other BCG-treated (n = 46, missing n = 4), and treatment naive groups (n = 47, missing n = 3), respectively. After 6 months, a CR of 46.0%, 71.7%, and 83.0% was found (p < 0.001). Subsequent 2-year recurrence rates were 17.4%, 27.3%, and 12.8%, respectively. The overall cystectomy-free rate and OS at mean follow-up (35.8 months) were 78.5% and 78.0%, respectively. These were 71.4% vs. 84.1% vs. 86.7% (cystectomy-free rate, p = 0.006) and 76.0% vs. 69.6% vs. 87.2% (OS, p = 0.06) for BCG-unresponsive vs. other BCG-treated vs. treatment naive patients. Progression to muscle-invasive disease was seen in 13.3% of patients. Patients stopped induction or maintenance RF-CHT instillations due to adverse events in respectively 13.4% and 17.8%. Conclusions: Intravesical RF-CHT showed good results in both treatment naive and BCG-treated CIS patients, avoiding the need for cystectomy in 78.5% of cases for at least 3 years with a modest risk of progression. Thus, RF-CHT proves an alternative to cystectomy in selected high-risk patients.