Evaluation of Volume of Nasopharyngeal Cancers by the Cavalieri Principle

Abstract

Prediction of tumor volume using the Cavalieri method may be helpful in management of therapy and evaluation of<br />treatment results. The aim of this study was to adapt the Cavalieri stereological method to magnetic resonance imaging<br />for determining volume of nasopharyngeal cancers and assess changes after treatment using the Cavalieri method.<br />Serial MRI images in the sagittal plane were obtained from a total of 33 patients with nasopharyngeal carcinomas<br />(11 with stage T2, 11 with stage T3, and 11 with stage T4 lesions). The images were analyzed retrospectively before<br />and two months following the cessation of radiochemotherapy for comparison. Average tumor volumes before and after<br />treatment in patients with stage T2 were 21. 5±10.5 cm3 and 2.82±3.43 cm3, respectively (p=0.000). The respective<br />figures were 35.1±19.0 cm3 and 6.27±7.82 cm3 (p=0.000) for stage T3 cases, and 62.8±27.8 cm3 and 11. 6±11.9 cm3<br />(p=0.000) for stage T4. Post-treatment tumor volumes were statistically reduced when compared to pre-treatment<br />volumes in all stages.