430 Preoperative measurement of tumor volume in early cervical cancer. is it reliable

Introduction/Background Maximum diameter-based tumour measurement is the standard method to asses tumour size and staging pre and postoperatively. Traditionally, clinically estimation of tumour size was the preferred preoperative measuring tool. Nowadays, thanks to the availability of advanced imaging techniques, preoperative staging could be done more precisely. Several studies have analysed the correlation between the tumour size measured with MRI and ultrasound and final pathology findings. In this study we analyse not only the correlation of diameter-based tumour size, but also the correlation of tumour volume estimation. Methodology A secondary analysis of the SUCCOR study was performed (European patients with FIGO 2009 stage IB1 cervical cancer that underwent radical hysterectomy from January 1st, 2013 to December 31st, 2014). Patients with previous conization were excluded. Patients with at least 3 different tumour measurements both in MRI or ultrasound and in the final pathology report were included. The 3 diameters measured to calculate the volume were defined as: craniocaudal diameter (dcc); anteroposterior diameter (dap) and the largest lateral diameter (dl). Tumour volume estimation was calculated using the ellipsoid formula (V = dcc x dap x dl x π/6). Intraclass Correlation Coefficient (ICC) was applied to study the correlation of diameter-based tumour size and tumour volume estimation between MRI and pathology report and Ultrasound and pathology report. Results 693 patients were included in the final analysis of SUCCOR study. 137 of them had both preoperative MRI with 3 different measures (Anteroposterior, Craniocaudal and largest lateral diameter) and pathology report. 81 patients had the 3 diameters measured preoperatively by ultrasound. When performing a preoperative MRI, the ICC between MRI and final pathology for maximum diameter size was 0.71 (0.61–0.78) and for tumour volume 0.53 (0.38–0.64). Preoperative ultrasound compared to final pathology report showed a ICC of 0–87 (0.8–0.91) for maximum diameter size and 0.64 (0.4–0.78) for tumour volume measurement. Conclusion Maximum diameter size showed a good correlation (ICC=0.75–0.9) with the pathology report when measured preoperatively by ultrasound and a moderate correlation (ICC=0.5–0.75) when measured by MRI. For tumour volume measurement both ultrasound and MRI showed a moderate correlation with the final pathology report. Disclosures All authors contributed to writing the manuscript and read and approved the final manuscript. The authors declare no conflict of interest.