Long-term efficacy of hyperthermic intravesical chemotherapy for BCG-unresponsive non-muscle invasive bladder cancer

Background: The recommended treatment for patients with Bacillus Calmette-Guérin (BCG) unresponsive non-muscle invasive bladder cancer (NMIBC) is radical cystectomy (RC). However, many patients refuse, or are unfit for RC. Therefore, alternative bladder-sparing treatment modalities are needed for BCG-unresponsive NMIBC. In this study we sought to assess the long-term efficacy of hyperthermic intravesical chemotherapy (HIVEC) as alternative to radical cystectomy in BCG-unresponsive non-muscle invasive bladder cancer patients. Methods and materials: Retrospectively collected data from 56 patients with BCG-unresponsive NMIBC who received ≥5 HIVEC instillations between October 2014 and March 2020 was analyzed. All patients met the BCG-unresponsive criteria according to the current EAU guideline on NMIBC 2020. Patients were followed-up with cystoscopy and/or bladder biopsies, urine cytology and annually CT-urography. The Primary outcome was the high grade (HG) recurrence-free survival (RFS), defined as the time from the first HIVEC instillation until histologically confirmed intravesical recurrence or last follow-up. The Kaplan Meier method was used to estimate survival outcomes. Secondary outcomes were: complete response rate (CR), adverse events (AE), assessed by the Common Terminology Criteria for Adverse Events v5.0 (CTCAE) and tumor progression to muscle invasive disease or distant metastases. Results: The median follow-up was 32.2 months (IQR 13.7–44.8). The 1- and 2-year HG-RFS was 53% (SE:6.8) and 35% (SE:6.9), respectively. The CR for patients with CIS was 70% (21/30) at 6 months. Overall, 80% of the population developed an AE, only 1 was classified as CTCAE ≥3. Limitation of this study was the small sample size. Conclusion: HIVEC resulted in a 2-year HG-RFS of 35% for BCG-unresponsive NMIBC patients without severe side-effects and therefore HIVEC seems to be an alternative treatment option for patients who refuse or are unfit for RC.