Celecoxib and Myrtol: A Novel Therapy for Recurrent Appendiceal Mucinous Neoplasms With Extensive Peritoneal Dissemination.

Background: Unresectable appendiceal mucinous neoplasms (AMNs) with extensive peritoneal dissemination cause significant morbidity and have limited treatment options. We evaluated a novel combination of Celecoxib and Myrtol in treating such AMNs.

Methods: Patients with recurrent AMNs with extensive peritoneal disease treated with a daily regimen of 200 mg Celecoxib and 1200 mg Myrtol Standardized were included. Progression-free survival (PFS) and overall survival (OS) were calculated, and carcinoembryonic antigen (CEA) trends were compared pretreatment and post-treatment in terms of percentage change.

Results: Thirteen patients with extensive, recurrent disease (median peritoneal carcinomatosis index of 36) were included between 2017 and 2020. The median age was 63 years (interquartile range: 55 to 67) and 7 (54%) were male. A total of 85% had undergone prior cytoreductive surgery while 15% underwent cytoreductive surgery >2 times. 54% had received multiple cycles of systemic chemotherapy before starting Celecoxib-Myrtol. After a median follow-up of 8 months, median PFS and OS were 16 months (interquartile range: 5 to 17) and 27 months, respectively. Nine (69.2%) showed improvement in CEA values 3 months after treatment compared with 3-month pretreatment CEA trends. None had adverse events attributable to Celecoxib-Myrtol.

Conclusions: Our feasibility study suggests that a regimen of Celecoxib-Myrtol is well tolerated and may prolong PFS and OS in patients with recurrent AMNs with peritoneal spread.