Intravesical thermochemotherapy in the treatment of high-risk and very high-risk non-muscle-invasive urothelial bladder cancer: a single-arm study.

Aim: Intravesical thermochemotherapy, also known as HIVEC (Hyperthermic Intra-VEsical Chemotherapy), represents an alternative adjuvant topical treatment for non-muscle-invasive urothelial bladder cancer (NMIBC). High-risk (HR) and very HR tumors carry a substantial risk of recurrence and progression. In this study, we present our own results using HIVEC as an alternative to unavailable Bacillus Calmette-Guérin (BCG) vaccine in the treatment of such groups of patients.

Methods: During the period of November 2014-June 2022, a total of 47 patients with HR and very HR NMIBC underwent treatment with HIVEC after transurethral resection. They were given an induction of 6 instillations with/without a maintenance. The aim was to evaluate the time to recurrence, event-free survival (recurrence or progression), as measured by Kaplan-Meier analysis, the effect of maintenance treatment and other factors on survival (log-rank test and multivariable Cox regression analysis), and complications.

Results: The median follow-up for patients who did not experience an event was 32 months. The median time to HR (high grade and/or T1 tumor) recurrence in those who recurred was 15 months. The survival rate without HR recurrence at 12, 24, and 48 months was 84, 70, and 59%, respectively. Progression was detected in 10.6% of patients, which translated to 89% of patients living without progression after 24 months. Maintenance treatment (defined as more than six instillations) and presence of CIS significantly correlated with risk of HR recurrence (Hazard ratio 0.34 and 3.12, respectively). One female patient underwent salvage cystectomy due to contractory bladder, and 19.1% of patients experienced transient lower urinary tract symptoms.

Conclusion: Based on our experience, HIVEC represents an adequate and safe alternative treatment for HR and very HR NMIBC in situations where BCG is not available or radical cystectomy is not an option for the patient. However, high-quality data from prospective randomized studies are still lacking, and thus, thermochemotherapy should still be regarded as an experimental treatment modality.