Challenges in Applying RECIST 1.1 in Advanced Ovarian Cancer

Background:It is essential to evaluate tumor burden by measuring its response or progression using established standards like RECIST 1.1, which is applicable to various organs., however its application in ovarian cancer (OC) are more challenging. Objective: To assess application of RECIST 1.1 criteria in advanced stage ovarian cancer (AOC) patients receiving NACT. Methods: This retrospective study had been performed on 100 female patients with pathologically confirmedAOC (FIGO stages III and stage IV) who had debulking surgery after receiving NACT, aged from 37 to 80 years old. Each patient underwent follow up CECT scans to evaluated tumor response to NACT prior to interval debulking surgery by RECIST 1.1 after selection of target lesions and non-target lesions. Results: There was a high percentage of ascites, peritoneal and omental involvement, which are considered by RECIST 1.1 to be non-measurable lesions. Non-target lesions were prevalent in a significant percentage of cases with advanced stage OC in contrast to target lesions, which were less than non-target lesions. Conclusions: Application of RECIST 1.1 to assess response to neoadjuvant-chemotherapy (NAC) in patient with advanced stage ovarian cancer relies mainly on non-target lesion.