Is it necessary to perform routine appendectomy for mucinous ovarian neoplasms? A retrospective study and meta-analysis.

OBJECTIVES: To evaluate whether routine appendectomy is necessary in all patients with mucinous borderline ovarian tumor (mBOT) or mucinous ovarian cancer (MOC) who undergo gynecologic surgery.

METHODS: The database of Qilu Hospital was searched for women who underwent appendectomy in a primary surgery for an ovarian tumor between June 2005 and June 2015 and whose final diagnosis was mBOT, MOC or primary appendiceal tumor. A retrospective review was performed, as well as a meta-analysis of the literature to further validate the findings.

RESULTS: Seventy-one patients, 29 with mBOT and 42 with malignant mucinous tumors (including 40 with primary MOC and 2 with appendiceal mucinous adenocarcinoma), underwent appendectomy at the time of primary surgery. Among those with mBOT, two (6.9%) appendices were grossly abnormal and pathologically diagnosed with appendiceal implantation by mBOT. In the 42 patients with malignant disease, five (12%) appendices had a grossly abnormal appearance, one (2.4%) was diagnosed with an appendiceal metastasis from MOC and two (4.7%) were primary appendiceal adenocarcinoma. For grossly normal appendices, only one (2.4%) was confirmed to have microscopic metastasis from MOC. The meta-analysis included a total of 914 mBOT and MOC cases with appendectomies, including our current cases. The estimated rate of overall appendiceal pathology is 4.97%, and the pooled odds ratio (OR) showed statistical differences between MOC and mBOT (MOC vs. mBOT, OR=2.15, P<0.05). The estimated malignant pathology rate in macroscopically normal vs. abnormal appendices is 1.4% and 59%, respectively, with an estimated OR up to 97.5 (95% CI 28.1-338.5, P<0.05).

CONCLUSION: There is not sufficient evidence to support a routine appendectomy for patients with a grossly normal appendix in mBOT and MOC. A careful intra-operative exploration of the appendix is crucial, but appendectomy is only warranted when the appendix is abnormal.