Identification of new lesion with disease progression in Ovarian cancer per RECIST 1.1.

Abstract

e18058 Background: Metastasis is the leading cause of ovarian cancer (OC) related death with more than 70% of OC patients diagnosed with metastasis with five-year survival rates below 45%. OC cells mainly metastasize within the peritoneal cavity at presentation and throughout the course of the disease in 85% of the patients which involves exfoliation from the primary tumor, followed by survival and transport in the peritoneal fluid and finally metastatic colonization of the organs within the peritoneal cavity. There is a tendency of conventional imaging to underestimate the frequency of peritoneal spread. The purpose of the study was to obtain the frequency of organ involvement in OC metastasis and identify the most common route of OC metastasis. Methods: Retrospective study and analysis of two randomized double-blind trials was performed in patients with OC. Data was analyzed from these studies using blinded independent central review using RECIST 1.1 involving a total of 895 subjects, 528 and 367 respectively. A double read with adjudication by independent radiologists was performed for each scan based on the RECIST 1.1 criteria. Baseline tumor burden was assessed for all subjects using RECIST 1.1 criteria. At follow-up visits, data was specifically analyzed for New lesions. The readers had to select New lesion location from a pre-defined location list from a drop-down menu. Data was tabulated with frequency of subjects with New lesion per each location. Results: With both studies combined involving 895 subjects, total subjects with new metastasis observed in decreasing order for various organs were peritoneum/omentum (406), lymph nodes (315), ascites (207), liver (94), pleural effusion (65), pelvis (52) & lung (56). Other less common locations for new metastasis was abdominal wall, pleural deposits, spleen, brain, retroperitoneum and adrenal. We also looked at the possibility of disagreement between 2 readers in identifying such lesions leading to progression as below. Conclusions: It can be concluded that subjects with ovarian cancer tend to develop metastasis leading to progression per RECIST 1.1 in peritoneum / omentum, lymph nodes, liver and lung. Due to significant variability in identification of such discrete, ill-defined and/or small nature of lesions, targeted awareness and training should be incorporated to improve clinical outcome. [Table: see text]