Residual tumour volumes and grey zones after external beam radiotherapy (with or without chemotherapy) in cervical cancer patients. A low-field MRI study.
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).


METHODS
T2-weighted MRI datasets of 175 patients with locally advanced cervical cancer (FIGO stage IB-IVA), who underwent combined external beam radiotherapy and brachytherapy with or without concomitant chemotherapy were available for this study. The gross tumour volume at the time of diagnosis (GTV(init)) and at the time of first brachytherapy without (GTV(res)) and with (GTV(res)+ GZ) consideration of grey zones were measured for each patient. A descriptive statistical analysis was performed and tumour regression rates without (R) and with consideration of grey zones (R(GZ)) were calculated. Further, the role of prognostic factors on GTV(init), GTV(res), GTV(res)+ GZ and tumour regression rates was investigated.


RESULTS
The median GTV(init), GTV(res), GTV(res)+ GZ in all patients were 44.4 cm(3), 8.2 cm(3), 20.3 cm(3), respectively. The median R was 78.5% and the median R(GZ) was 50.1%. The histology and FIGO staging showed a significant impact on GTV(init), GTV(res) and GTV(res)+ GZ.


CONCLUSIONS
Grey zones represent a substantial proportion of the residual tumour volume at the time of brachytherapy. Differentiation of high signal intensity mass and surrounding intermediate signal intensity grey zones may be reasonable.
Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, General Hospital of Vienna, 18-20 Währinger Gürtel, 1090, Vienna, Austria. maximilian.schmid@akhwien.at
M P
MP
Schmid
B
B
Mansmann
M
M
Federico
J C A
JC
Dimopoulous
P
P
Georg
E
E
Fidarova
W
W
Dörr
R
R
Pötter
D000230:Adenocarcinoma / Q000175:diagnosis / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D002584:Cervix Uteri / Q000473:pathology / Q000528:radiation effects; D059248:Chemoradiotherapy / Q000379:methods; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000175:diagnosis / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D011379:Prognosis; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D019233:Retreatment; D047368:Tumor Burden / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*