INTRODUCTION
Epithelial ovarian carcinoma (EOC) has an annual incidence of 11.0 and a mortality rate of 7.3 cases per 100.000 women within the Netherlands1. Approximately 30% of the EOC patients present with clinically early-stage (i.e., FIGO stage I-II) disease at initial evaluation2. The treatment plan of clinically early-stage EOC is determined by comprehensive surgical staging, enabling valid prognosis estimates and, more importantly, determines adjuvant treatment.
The ten-year follow-up data from the European Organisation for Research and Treatment of Cancer – Adjuvant ChemoTherapy in Ovarian Neoplasm (EORTC-ACTION) – trial demonstrated complete staging surgery was significantly associated with a superior recurrence-free and overall survival. Adjuvant chemotherapy appeared only beneficial in clinically early-stage EOC patients with possible unidentified residual disease due to absent or incomplete staging surgery3,4.
As recommended by the International Federation of Gynecology and Obstetrics (FIGO), a comprehensive staging surgery should include a hysterectomy, bilateral salpingo-oophorectomy, cytology of ascites or peritoneal washings, peritoneal biopsies, infracolic omentectomy, and pelvic- and para-aortic lymphadenectomy5,6. Although the clinical relevance of surgical staging has been unequivocally proven based on multiple trials, the variation in upstaging rates in literature hinders the adequate selection of patients who will benefit from adjuvant chemotherapy. Up to one-third of these clinically early-stage EOC patients are reported to be upstaged following staging surgery. However, exact upstaging rates vary widely between individual studies, mainly due to case-mix differences7,8.
With this systematic review and meta-analysis, we aim to determine the upstaging rate after comprehensive surgical staging, and its components, in patients with clinically early-stage EOC. The influence of clinical factors, such as histological type, differentiation grade, and lymph node assessment method, will be studied. Furthermore, we aim to clarify the difference between finding metastatic disease and its contribution in the upstaging rate in patients.