Residual tumour volumes and grey zones after external beam radiotherapy (with or without chemotherapy) in cervical cancer patients

Background Grey zones, which are defined as tissue with intermediate signal intensity in the area of primary hyperintense tumour extension, can be seen during radiation with or without chemotherapy on the T2-weighted MRI in patients with cervical cancer. The purpose of this study was to systematically measure the tumour volume at the time of diagnosis and the residual tumour volume at the time of brachytherapy without and with consideration of the grey zones and to estimate tumour regression during external beam radiotherapy (EBRT).