554P - Tumor assessments according to recist versus volumetry: impact on early changes in tumor size in metastatic colorectal cancer (mCRC)

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Colon Cancer
Rectal Cancer
Presenter Rüdiger Laubender
Authors R. Laubender1, U. Sartorius2, M. Schlichting3, S. Stintzing4, A. Graser5, V. Heinemann6
  • 1University Of Munich, Institute of Medical Informatics, Biostatistics, and Epidemiology, 81377 - Munich/DE
  • 2Global Clinical Development Unit Oncology, Merck KGaA, Darmstadt/DE
  • 3Biostatistics, Merck KGaA, Darmstadt/DE
  • 4Hämatologie Und Onkologie, Klinikum Grosshadern, University of Munich, Munich/DE
  • 5Klinikum Grosshadern, University of Munich, Munich/DE
  • 6Dept. Of Medicine Iii, Klinikum Grosshadern, University of Munich, Munich/DE

Abstract

Background

We previously proposed an algorithm for reconstructing the true volume of a tumor lesion by using the longest diameter (LD) and the longest orthogonal diameter (LOD). The following analyses aimed to replicate these findings and evaluate the agreement between RECIST-based tumor assessments (TA) and volumetry in the quantification of early changes in tumor size.

Material and methods

mCRC patients (pts) treated with FOLFIRI-based therapy at the University Hospital of Munich underwent routine staging using contrast-enhanced CT scans. At least 2 hepatic target lesions per pt were defined by 2 raters at baseline and assessed every 8 weeks using semi-automated volumetry (Siemens Syngo Via Oncology) and manual measurement of the LD (RECIST 1.1) and the LOD. Agreement between the tumor volume algorithm and volumetry for each rater and the corresponding inter rater agreement (IA) were investigated using Bland-Altman (BA) plots. Agreement between the RECIST-based and volumetry-based relative changes was quantified by intraclass correlation (ICC) where 1.0 would indicate perfect agreement.

Results

222 target lesions from 25 pts were measured at 99 TAs. BA plots indicated that the volume algorithm showed negligible constant bias for both raters (rater 1, 0.09 with p = 0.25, and rater 2 -0.05 with p = 0.41). IA with regard to the volumetry showed a smaller constant bias (-0.16 with p = 0.17) compared with the volume algorithm (-0.31 with p = 0.04). The relative change in tumor size between baseline and first TA was investigated. The ICCs for RECIST-based versus volumetry-based relative changes for the 2 raters were 0.79 and 0.62. Application to mCRC patients from the CRYSTAL (n = 1198) and OPUS (n = 337) studies showed the ICCs for RECIST-based versus volume algorithm-based relative changes to be 0.60 and 0.77.

Conclusions

The algorithm for estimating the tumor volume was validated as demonstrated by the negligible bias and the BA plots. The moderate ICCs for early changes in tumor size in the 25 Munich pts and those from the CRYSTAL and OPUS studies indicate clear differences between RECIST- and volume-based TAs and suggest that RECIST underestimates both tumor shrinkage and tumor growth.

Disclosure

R. Laubender: RPL receives travel support and research funding by Merck KGaA.

U. Sartorius: The author is an employee of Merck KGaA.

M. Schlichting: The author is an employee of Merck KGaA.

S. Stintzing: The author receives: Honoraria and travel support from Merck Serono and Roche AG Honoraria from Amgen GmbH.

A. Graser: The author declares that he is a member of the Siemens speakers' bureau and that he receives grant money from Bayer Pharma.

V. Heinemann: The author declares: Honoraria (lectures) from Merck, Roche, Sanofi Honoraria (Ad Boards) from Merck, Roche, Sanofi Research support from Merck, Roche, Sanofi.