Value of apparent diffusion coefficient (ADC) in evaluating response of carcinoma of the cervix treated with chemoradiotherapy
Abstract
Objective. To determine whether the apparent diffusion coefficient (ADC) value obtained by diffusion-weighted magnetic resonance imaging
(DW-MRI) can be used as a reliable detector of response of carcinoma of the cervix treated with chemoradiotherapy, compared with conventional
T2-weighted MRI.
Design. A prospective cohort study was performed.
Setting. Department of Oncology, Universitas-National Hospital Complex, Bloemfontein.
Subjects. Seventeen women with advanced cervical cancer, FIGO staging IIB - IVB, were selected for chemoradiation.
Outcome measures. Patients underwent pelvic MRI before therapy, 14 days after onset of therapy, and in the last week of treatment (5th/6th
week). Axial and sagittal conventional T2 was followed by DW-MRI in the axial plane from which a tumour region of interest (ROI) was manually drawn to calculate ADC values using b-values of 500 and 1 000 s/mm2.
Results. ADC values for cervical carcinoma increased after treatment with chemoradiation. The most significant observation was seen 14 days
after treatment was started. The mean ADC value increased with 20% (b=500 s/mm2) and 24% (b=1 000 s/mm2) (statistically significant, p<0.05) compared with a decrease in tumour size of only 8%, which was not statistically significant (p=0.075). Responders showed a larger change in ADC values than non-responders.
Conclusion. The study showed considerable promise in the ability of ADC to identify early tumour response to therapy. DW-MRI is a non-invasive
functional imaging technique that may in future change management in oncology by early identification of non-responders, hence avoiding
unnecessary treatment.
(DW-MRI) can be used as a reliable detector of response of carcinoma of the cervix treated with chemoradiotherapy, compared with conventional
T2-weighted MRI.
Design. A prospective cohort study was performed.
Setting. Department of Oncology, Universitas-National Hospital Complex, Bloemfontein.
Subjects. Seventeen women with advanced cervical cancer, FIGO staging IIB - IVB, were selected for chemoradiation.
Outcome measures. Patients underwent pelvic MRI before therapy, 14 days after onset of therapy, and in the last week of treatment (5th/6th
week). Axial and sagittal conventional T2 was followed by DW-MRI in the axial plane from which a tumour region of interest (ROI) was manually drawn to calculate ADC values using b-values of 500 and 1 000 s/mm2.
Results. ADC values for cervical carcinoma increased after treatment with chemoradiation. The most significant observation was seen 14 days
after treatment was started. The mean ADC value increased with 20% (b=500 s/mm2) and 24% (b=1 000 s/mm2) (statistically significant, p<0.05) compared with a decrease in tumour size of only 8%, which was not statistically significant (p=0.075). Responders showed a larger change in ADC values than non-responders.
Conclusion. The study showed considerable promise in the ability of ADC to identify early tumour response to therapy. DW-MRI is a non-invasive
functional imaging technique that may in future change management in oncology by early identification of non-responders, hence avoiding
unnecessary treatment.
