Rate of Appendiceal Metastasis with Non-Serous Epithelial Ovarian Cancer in Manitoba

OBJECTIVE: This study sought to evaluate the rate of appendiceal involvement in non-serous mucinous and endometrioid-associated epithelial ovarian cancers. METHODS: The Manitoba Cancer Registry and CancerCare database were used to find all women with non-serous epithelial ovarian, fallopian tube, or primary peritoneal cancer between 1995 and 2011. All patients with an appendectomy were then identified, and their final pathology findings were reviewed. Women who did not receive treatment or lacked follow-up were excluded. RESULTS: We identified 338 patients from 1995-2011 with no prior appendectomy. Of these, 16.6% received an appendectomy, and 22.8% were clinically evaluated. Most cases within this cohort were mucinous (62%) and stage 1 (63%). Four appendiceal metastases were identified (7.2%), and one half appeared clinically normal at the time of surgery (3.6%). Within the mucinous histologic type, 32.7% of patients received an appendectomy, with a metastatic rate of 5.7%. Of the 127 endometrioid cases, only 10 patients received an appendectomy, and 2 were found to have metastases. No metastases were found in the 85 patients in the clear cell cohort, only 5 of whom received an appendectomy. CONCLUSION: Routine appendectomy or clinical assessment of the appendix is valuable for all non-serous ovarian cancers. The rate of involvement for endometriosis-associated ovarian cancers may be significantly higher than expected, and further studies need to be conducted.