Quantitative analysis of mean ADC in cervix cancer patients during chemoradiotherapy
Datta, Anubhav Dubec, Michael Cree, Anthea Mistry, H. Hoskin, Peter J
Datta, Anubhav
Dubec, Michael
Cree, Anthea
Mistry, H.
Hoskin, Peter J
Citations
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Abstract
Purpose or Objective
A pilot study to evaluate changes in mean apparent
diffusion coefficient (ADC) as a quantitative imaging
biomarker during chemoradiotherapy prior to
implementation on the MR Linac (MRL).
Material and Methods
A sample of 6 patients undergoing curative-intent
concurrent chemoradiotherapy (CRT) for locally advanced
cervical cancer (LACC) were enrolled into a prospective
observational imaging study. Sagittal T2 weighted (T2W)
and diffusion weighted imaging (DWI) sequences were
obtained at three time points during external beam
radiotherapy (EBRT). These were in addition to the regular
imaging protocol. Conventional ADC maps were calculated
and co-registered to the T2W images. A radiologist
delineated the tumour volume of interest on the T2W
sequences and mean ADC values were calculated. Patients
with serial tumour volume reduction at diagnostic MR
imaging were classified as imaging-based responders using
the Response Evaluation Criteria in Solid Tumors (RECIST)
criteria1,2
Results Patients 1-5 were all responders and patient 6 was a nonresponder.
The responders demonstrate a serial increase
in mean ADC values during chemoradiotherapy with a
positive correlation (Spearman’s rs = 0.69; t=3.42;
p=0.005). CRT affects the tumour microarchitecture and
integrity of cell membranes. ADC, which measures the rate
of water mobility, increases after successful therapy
because cell density decreases and reflects cell death3.The
solitary non-responder (Patient 6) did not demonstrate this
trend with a fall in mean ADC value at the third time point.
This tumour was a high grade, poorly differentiated,
adenosquamous carcinoma which may explain the poor
response.
Conclusion
During CRT, cervical tumour mean ADC values serially
increase in those patients responding to treatment. This
pattern was not seen in the non-responding patient. This supports the role of serial functional imaging during
chemoradiation as a biomarker, and will inform our
protocols when commissioned on the MRL which has a
similar 1.5T magnet to the diagnostic MR used in this
study.
Description
Date
2020
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Datta A, Dubec M, Cree A, Mistry H, West C, Choudhury A, et al. PO-1696: Quantitative analysis of mean ADC in cervix cancer patients during chemoradiotherapy. Radiotherapy and Oncology . 2020 Nov;152:S934–5.