Preoperative Prediction of Malignancy and Surgical Treatment Strategy for Appendiceal Tumors: Multicenter Review of 51 Consecutive Cases

Purpose: A diagnostic and treatment strategy for appendiceal tumors (ATs) has not been established. We aimed to evaluate our treatment strategy for ATs including laparoscopic surgery (LS) and to identify preoperative malignancy predictors. Methods: : A total of 51 patients were retrospectively reviewed. Data including tumor markers and imaging findings were compared between carcinoma and non-carcinoma patients. Validity of planned operation was evaluated based on pathological diagnosis. Results: : Twenty-five patients were diagnosed with carcinoma, 13 with low-grade mucinous neoplasm, and 13 with other diseases. Symptoms were more commonly present in carcinoma patients than in non-carcinoma patients (68.0% vs. 23.1%, p =0.001). Elevated CEA and CA19-9 were more frequently observed in carcinoma patients than in non-carcinoma patients ( p <0.01 and p =0.04, respectively). Five carcinoma patients had malignancy on biopsy, compared with zero non-carcinoma patients. Significant differences were noted in the percentages of carcinoma and non-carcinoma patients with solid enhanced mass (41.7% vs. 0%, p <0.001) and tumor wall irregularity (16.7% vs. 0%, p =0.03) on imaging. Although the sensitivity was not high, the specificity and positive predictive value of these findings were 100%. Forty-two patients (82.4%) underwent LS as minimally invasive exploratory tool and/or radical operation, of whom 2 were converted to open surgery for invasion of adjacent organ. None of the patients had intraoperative complications or postoperative mortality. Conclusion: Clinical symptoms, elevated tumor markers, and worrisome features of solid enhanced mass and tumor wall irregularity on imaging can be malignancy predictors. For management of AT patients, LS is feasible and useful for diagnosis and treatment.