Prior appendectomy does not protect against subsequent development of malignant or borderline mucinous ovarian neoplasms

article i nfo Background.Duetoconcernthatmucinousmalignantorborderlineovarianneoplasms(MON)mayrepresent metastatic deposits from appendiceal primaries, gynecologic oncologists routinely perform appendectomy in these cases. However, a multidisciplinary critique of this practice is lacking. Methods. The New England Case-Control study database was utilized to compare the effect of prior appen- dectomy against known risk factors for MON. Pathology and operative reports of local cases of MON were reviewedtoestimatethefrequencyofmicroscopicmucinouslesionsintheappendix.Proteinexpressionpatterns among mucinous ovarian, colorectal, and appendiceal cancers were compared by immunohistochemistry. Results. From the New England Case-Control study, 287 cases of MON were compared against 2339 age- matched controls. Prior appendectomy did not reduce the risk of MON (OR 1.28, 95% CI 0.83-1.92, p = 0.23), while prior tubal ligation, parity, and breastfeeding were each protective against MON. Active smoking (OR 2.04, 95% CI 1.48-2.80, p b 0.001) was associated with an increased risk of MON. Among 196 mucinous adnexal