BACKGROUND. Bidimensional tumor measurements are used routinely as surrogat
es for tumor volume. The purpose this study was to determine whether there
is any added benefit in bidimensional or tridimensional measurements over a
unidimensional measurement.
METHODS. Sixty-nine colorectal hepatic metastases on 19 computed tomography
scans (1-8 lesions per scan) from 9 patients were analyzed. Five patients
contributed 2-4 scans each (mean, 3 scans). The standard Volume of these le
sions was determined by the "summation of areas" technique. The maximum axi
al dimension, the product of the greatest axial dimensions, and several vol
ume estimates (based on the volumes of a sphere, an ellipsoid, and a cube)
each were correlated with the standard volume.
RESULTS. The maximum axial dimension and the product of the greatest axial
dimensions correlated equally with tumor volume (correlation coefficient =
0.93). Surrogate measures based on the equations for a sphere and an ellips
oid underestimated tumor volume, whereas the equation for a cube overestima
ted volume.
CONCLUSIONS. When reporting tumor size, there is no significant added benef
it in reporting bidimensional or tridimensional measurements over the maxim
um axial dimension. (C) 2001 American Cancer Society.