A comparison of pathological methods of measuring lung cancer volume

To determine which of several pathological methods of measuring lung cancer volume compared most favourably with the gold standard.

Three pathological methods were used on 54 resected lung cancers: (1) measuring the maximum dimension and assuming a spherical shape; (2) measuring three dimensions and assuming an ellipsoidal shape; and (3) deriving the volume from the area of tumour on sequential 1 cm slices using a photocopier and an image analysis system. The gold standard was obtained from the area of whole mount tumour sections on sequential 0.1 cm slices of eight cancers.

Volumes derived from 1 cm lung slices gave results closest to our gold standard but assuming tumours were ellipsoidal was only a slightly less accurate and less time consuming method. Assuming cancers were spherical resulted in gross overestimation of the tumour volumes.

For practical purposes, it is reasonable to measure three dimensions of a lung tumour at sectioning and calculate the volume using the formula for an ellipsoid (V = 4/3 pi d.e.f, where d, e and f are the semi-axes).