Background Observational studies have supported the practice of offering minimally invasive interval debulking surgery after neoadjuvant chemotherapy for well-selected patients with advanced epithelial ovarian cancer. However, there are no prospective randomized data comparing the oncologic efficacy of minimally invasive and open interval debulking surgery in epithelial ovarian cancer.

Primary objective The primary objective of this study is to examine whether minimally invasive surgery is non-inferior to laparotomy in terms of disease-free survival in women with advanced stage epithelial ovarian cancer that responded to three or four cycles of neoadjuvant chemotherapy.

Study hypothesis We hypothesize that in patients who had a complete or partial response to neoadjuvant chemotherapy, minimally invasive interval debulking surgery is not inferior to laparotomy.

Trial design The Laparoscopic cytoreduction After Neoadjuvant ChEmotherapy (LANCE) trial is an international, prospective, randomized, multicenter, non-inferiority phase III trial to compare minimally invasive surgery vs laparotomy in women with advanced stage high-grade epithelial ovarian cancer that had a complete or partial response to three or four cycles of neoadjuvant chemotherapy and normalization of CA-125. The first 100 participants will be enrolled into a pilot lead-in to determine feasibility. The study will be considered feasible and will continue to Phase III under the following conditions: the accrual rate reaches at least 80% of the target rate after all pilot sites are open; the crossover rate in the minimally invasive group is less than 25%; and the difference of complete gross resection between the minimally invasive and open group is less than 20%. If the study is determined to be feasible, all remaining participants will be enrolled into the Phase III stage.

Major inclusion/exclusion criteria Patients with stage IIIC or IV high-grade epithelial ovarian, primary peritoneal or fallopian tube carcinoma who had a complete or partial response to three or four cycles of neoadjuvant chemotherapy based on imaging and normalization of CA-125 will be enrolled. Patients with evidence of tumor not amenable to minimally invasive resection on pre-operative imaging will be excluded.

Primary endpoint The primary endpoint is non-inferiority of disease-free survival in minimally invasive vs laparotomic interval debulking surgery.

Sample size To demonstrate non-inferiority with a margin of 33% in the hazard ratio (HR=1.33), 549 patients will be randomized.