Management of Primary Retroperitoneal Mucinous Tumors: A Retrospective Meta-Analysis.

OBJECTIVE: Primary retroperitoneal mucinous tumors (PRMTs) are rare epithelial neoplasms arising in the retroperitoneal space whose pathogenesis is poorly understood. To date, only single-case reports and small case series on diagnosis and management of these tumors exist. The aim of this first-time meta-analysis was to provide more reliable data to inform the management of PRMTs.

METHODS: Database searches were conducted to identify case reports and case series between the years of 1975 and 2015. Two cases of patients treated at our institution were also included. Diagnostic, radiographic, surgical, and follow-up data were gathered. Regression modeling was used to identify factors aiding preoperative diagnosis and affecting treatment. Survival analysis including Cox regression modeling was performed to provide insights into treatment effects on the prognosis of female patients with PRMTs.

RESULTS: One hundred forty-four cases of PRMTs were included in this analysis. Eighty-nine percent occurred in women. Most of the PRMTs were found to be malignant (53%). No preoperative factors predicting tumor dignity were identified by multiple regression analysis. Five-year disease specific survival of patients with benign and borderline tumors was excellent, reaching 100%, whereas it was only 68% for patients with malignant disease. Adjuvant surgical treatments including hysterectomy, salpingoophorectomy, and lymph node dissection were not associated with a statistically significant survival advantage. However, there was a nonsignificant association of hysterectomy with improved survival (hazard ratio, 0.42; 95% confidence interval, 0.09-2.07; P = 0.285). Adjuvant chemotherapy was associated with reduced survival (hazard ratio 3.791; 95% confidence interval, 1.509-9.526; P = 0.0046).

CONCLUSIONS: A reliable diagnosis of a PRMT can only be made by pathological examination of the tumor. Surgical excision is thus necessary to facilitate diagnosis while it also remains the mainstay of treatment. There is no conclusive evidence supporting the role of adjuvant surgical procedures or chemotherapy.