Correlation between CT-estimated tumor volume, pathologic tumor volume, and final pathologic specimen weight in children with Wilms' tumor

ObjectiveTo evaluate the relationship of Wilms' tumor (WT) volume to weight, and evaluate computed tomography (CT) scan-derived final pathologic specimen weight estimation models.MethodsWe retrospectively reviewed WT patients from 2003 to 2011 who had a pre-operative CT scan, final pathologic specimen weight, and tumor dimensions. A partial nephrectomy tumor cohort (n = 12) was used derive WT density. A radical nephrectomy cohort (n = 45) was used to develop a simplified estimation equation of final pathologic specimen weight, and analysis of all known estimation models was performed.ResultsFifty-two patients were identified. WT volume and weight were not equivalent (p = 0.0410). WT density was 1.3091 g/cm3. WT volume and final pathologic specimen weight were not significant (p = 0.0007). Our model (p = 0.9983) and CT estimated ellipsoidal volume (p = 0.0741) were able to estimate final pathologic specimen weight in all tumors. However, CT-estimated ellipsoidal volume failed to estimate final pathologic specimen weight in specimens < 250 g (p = 0.0066).ConclusionPathologic WT volume is not equivalent to final pathologic specimen weight. Final pathologic specimen weight can be estimated from a pre-operative CT scan, which suggests that it may be used to improve pre-operative surgical planning and to reduce treatment morbidity.