Assessment of Volumetric versus Manual Measurement in Disseminated Testicular Cancer; No Difference in Assessment between Non-Radiologists and Genitourinary Radiologist

BACKGROUND The aim of this study was to assess the feasibility and reproducibility of semi-automatic volumetric measurement of retroperitoneal lymph node metastases in testicular cancer (TC) patients treated with chemotherapy versus the standardized manual measurements based on RECIST criteria. METHODS 21 TC patients with retroperitoneal lymph node metastases of testicular cancer were studied with a CT scan of chest and abdomen before and after cisplatin based chemotherapy. Three readers, a surgical resident, a radiological technician and a radiologist, assessed tumor response independently using computerized volumetric analysis with Vitrea software® and manual measurement according to RECIST criteria (version 1.1). Intra- and inter-rater variability were evaluated with intra class correlations and Bland-Altman analysis. RESULTS Assessment of intra observer and inter observer variance proved non-significant in both measurement modalities. In particularly all intraclass correlation (ICC) values for the volumetric analysis were > .99 per observer and between observers. There was minimal bias in agreement for manual as well as volumetric analysis. CONCLUSION In this study volumetric measurement using Vitrea software® appears to be a reliable, reproducible method to measure initial tumor volume of retroperitoneal lymph node metastases of testicular cancer after chemotherapy. Both measurement methods can be performed by experienced non-radiologists as well.