Endoclips as novel fiducial markers in trimodality bladder-preserving therapy of muscle-invasive bladder carcinoma: feasibility and patient outcomes

Hypothesis: Endoclip can be used as fiducial marker in urology. Objective: To assess the feasibility, cost effectiveness and reliability of endoclips as novel fiducial markers in precision radiotherapy, as part of a trimodality bladder-preserving treatment (TBPT) of muscle-invasive bladder carcinoma. Materials and Methods: This retrospective study was performed at Weifang People's Hospital (Weifang, China) from January 2015 to June 2018. A total of 15 patients underwent TBPT. Endoclips were applied to healthy edges of the resected bladder wall as novel fiducial markers. Radio-sensitizing chemotherapy and routine precision radiotherapy were given. The number and position of the endoclips during radiotherapy sessions were monitored. Complications and tumor recurrence were analyzed. esults: The mean age (+/- standard deviation) of the patients was 67 +/- 10 years (range 46-79). There were 3 females and 12 males. Forty-nine endoclips were applied in all patients (3.3 +/- 0.8). The tumor was completely visibly resected in all patients. The number of endoclips remained the same through the planned last radiotherapy session (3.3 +/- 0.8), i.e., none were lost. All endoclips were removed after the last radiotherapy session. The average number of follow-up months was 38.9 +/- 13.2 (range 11-52). There were no procedure-related complications at discharge or follow-up. At one-year, overall recurrence-free survival was 93.3%. Two patients had recurrences at 18 months and 10 months after TBPT, respectively, and salvage radical cystectomy was performed with no further recurrences. Another patient died due to metastasis 9 months after the completion of therapy. Conclusions: Endoclips are reliable, safe and cost-effective as novel fiducial markers in precision-radiotherapy post-TBPT.