ADC predicts persistent cervical lymph node disease following curative (chemo)radiotherapy
Salah, Amal Jain, Yatin Bonington, Suzanne C France, A. Buckley, D. Eccles, Cynthia L McPartlin, Andrew J
Salah, Amal
Jain, Yatin
Bonington, Suzanne C
France, A.
Buckley, D.
Eccles, Cynthia L
McPartlin, Andrew J
Citations
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Abstract
Purpose or Objective
The value of diffusion weighted (DW)-MRI post (chemo)radiotherapy ((C)RT) to assess disease response in
malignant cervical lymph nodes (LN) is incompletely understood. We assess the correlation between apparent
diffusion coefficient (ADC) of cervical LN post (C)RT and subsequent neck dissection histopathology.
Materials and Methods
Patients treated with (C)RT for head and neck squamous cell carcinoma at a single institution with post-treatment MRI followed by surgical neck dissection from January 2017 - January 2020 were identified for this
retrospective study. MRI scans were acquired at 1.5 T or 3 T on one of three scanners (Siemens Aera, Siemens
Skyra, and GE Signa), and included structural sequences and DW-MRI with automatically generated ADC maps.
The DW-MRI sequence parameters were comparable on all three scanners (b-values = 50 and 800 s/mm²).
However, due to the limited field of view of the sequence, and the prioritisation of imaging primary disease,
some of the DW-MRI scans did not include the full extent of neck nodes. Two experienced readers drew
regions of interest (ROI) on the ADC maps over all identifiable cervical LN with a diameter greater than 5 mm,
blinded to histopathological diagnoses, using the picture archiving and communication system (PACS). Mean
and minimum ADC values (ADCmean and ADCmin) of each node were measured on the PACS workstation (by
assessing the ADC of all pixels within the ROI) and matched to histopathological findings following neck
dissection. An un-paired t-test was used to compare ADC values for benign and malignant cervical lymph
nodes, with P < 0.05 considered statistically significant. Threshold ADC values for the detection of cervical LN
malignancies were calculated using receiver operating characteristic (ROC) analysis.
Results
31 cervical LN were identified in 18 patients. However, the ADCmin for two of the LN was 0 mm²/s, which may
imply a failure in the ADC estimation, hence those two LN were excluded from analysis. For the remaining 29
nodes (14 malignant and 15 benign as confirmed on histology), there was no statistically significant difference
between ADCmean for malignant (1.17 ± 0.36 x 10¯³ mm²/s) vs. benign (1.40 ± 0.53 x 10¯³ mm²/s) nodes (p = 0.18). A statistically significant difference was seen between ADCmin for malignant (0.42 ± 0.30 x 10¯³ mm²/s)
vs. benign (0.72 ± 0.37 x 10¯³ mm²/s) nodes (p = 0.02). The ROC analysis indicated that an ADCmean threshold <
1.49 x 10¯³ mm²/s detected disease with 86% sensitivity, 33% specificity, and 59% accuracy. Whilst an ADCmin
threshold < 0.69 x 10¯³ mm²/s had 86% sensitivity, 60% specificity, and 72% accuracy Conclusion
ADCmin shows value in predicting persistent lymph node malignancy post-(C)RT in primary head and neck
cancer and appears more discriminatory than ADCmean. Further prospective studies in a larger sample size are
warranted.
Description
Date
2021
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Salah A, Jain Y, Bonington S, France A, Buckley D, Eccles C, et al. ADC predicts persistent cervical lymph node disease following curative (chemo)radiotherapy. Radiotherapy and Oncology. 2021;161:S69-S70.