A case of pseudomyxoma peritonei successfully treated with trifluridine/tipiracil (TAS-102) and bevacizumab after palliative debulking surgery.

Pseudomyxoma peritonei is a rare disease with a reported prevalence of about 1-3 per million people annually. Cytoreductive surgery and perioperative hyperthermic intraperitoneal chemotherapy are considered as treatment options improving disease control or long-term survival. However, for patients with incomplete cytoreduction or debulking surgery, outcomes are significantly poorer compared with patients who have obtained complete or optimal cytoreduction. In cases of high-grade pseudomyxoma peritonei that are considered inoperable and/or unresectable, combination chemotherapy regimen with a neo-angiogenesis inhibitor such as bevacizumab is recommended. In this report, a 62-year-old Japanese man presented with abdominal distention. Examination of ascites demonstrated a jelly-like consistency and peritoneal pseudomyxoma was suspected. To relieve progressive symptoms, palliative debulking surgery with total colectomy was performed. Postoperative pathology confirmed high-grade appendiceal mucinous neoplasm with high-grade pseudomyxoma peritonei. In our case, combination chemotherapy with trifluridine/tipiracil (TAS-102) and bevacizumab was initiated after palliative debulking surgery. As a result, carcinoembryonic antigen level was kept stable and the volume of ascites remained almost the same as at the beginning of treatment for more than 2 years. In conclusion, combination chemotherapy comprising TAS-102 and bevacizumab in patients with palliative debulking could be a useful option for patients with high-grade mucinous appendiceal neoplasm and high-grade pseudomyxoma peritonei.