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

OBJECTIVE: To evaluate the relationship of Wilms' tumor (WT) volume to weight, and evaluate computed tomography (CT) scan-derived final pathologic specimen weight estimation models.

METHODS: We 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.

RESULTS: Fifty-two patients were identified. WT volume and weight were not equivalent (p = 0.0410). WT density was 1.3091 g/cm(3). 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).

CONCLUSION: Pathologic 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.