Recurrence of initially localized appendiceal mucinous neoplasms after radical resection: survey analysis and literature review

Background Appendiceal mucinous neoplasm (AMN) is a rare tumor that may be successfully treated by appendectomy. However, some patients develop recurrence as pseudomyxoma peritonei. The present study investigated the recurrence rate after radial resection for AMN. Methods A survey on AMN was sent to 171 institutions, and 286 cases were analyzed. The risk of recurrence was assessed according to clinical parameters. Recurrence rates were compared with data from the literature. Results There were 250 cases in the low-grade group and 36 in the high-grade group, with perforation being detected in 50 cases. After a median follow-up period of 30 months, recurrence was detected in 17 cases, including 12 with high-grade histology and 10 with perforation. Two patients with low-grade histology and no perforation developed recurrence. Independent prognostic factors for recurrence were high-grade histology ( p = 0.0001, RR = 8.56) and perforation ( p = 0.0168, RR = 3.45). Four groups were classified by histology and perforation: group A: high-grade, perforation ( +), group B: high-grade, perforation (−), group C: low-grade, perforation ( +), group D: low-grade, perforation (−). Five-year recurrence rates in groups A, B, C, and D were 46.7, 25.9, 13.3, and 1.5%, respectively. All cases of recurrence were detected within 3 years, except for two in group B. Conclusions Recurrence in cases with low-grade histology and no perforation was rare; however, a postoperative survey for at least 3 years is required. In contrast, cases with high-grade histology or perforation need to be monitored using a similar approach to colon cancer. Prophylactic CRS + HIPEC may be considered.