Table 5.

Comparison of primary tumour and nodal ADC_mean and ADC_min values for vROI, aROI, rROI between participants with and without 2 year DFS : HPV OPC and other HNSCC

Variable	No 2 year DFS ADC (10−6 mm2/s)		2 year DFS ADC (10−6 mm2/s)		p-value
Other HNSCC	n		n
Lymph node vROI ADCmean	4	1071 ± 263	10	1063 [1091,1358]	0.73
Lymph node vROI ADCmin	4	923 ± 169	10	846 ± 206	0.77
Lymph node aROI ADCmean	4	1082 ± 289	10	1101 [962, 1375]	0.76
Lymph node aROI ADCmin	4	934 ± 174	10	814 [668, 926]	0.71
Lymph node rROI ADCmean	4	990 [888, 1059]	10	955 ± 182	0.70
Lymph node rROI ADCmin	4	919 ± 168	10	808 ± 167	0.85
Primary tumour vROI ADCmean	6	1128 ± 181	13	1018 ± 183	0.81
Primary tumour vROI ADCmin	6	823 ± 203	13	789 ± 162	0.76
Primary tumour aROI ADCmean	6	1138 ± 179	13	978 ± 190	0.76
Primary tumour aROI ADCmin	6	849 ± 193	13	776 ± 184	0.74
Primary tumour rROI ADCmean	6	1122 ± 224	13	863 [779, 996]	0.81
Primary tumour rROI ADCmin	6	836 ± 216	13	778 ± 182	0.66

Variable	No 2 year DFS ADC (10−6 mm2/s)		2 year DFS ADC (10−6 mm2/s)		p-value
HPV OPC	n		n
Lymph node vROI ADCmean	4	938 [872, 1098]	41	1002 [898, 1142]	0.50
Lymph node vROI ADCmin	4	679 ± 99	41	814 ± 208	0.21
Lymph node aROI ADCmean	4	962 [839, 1052]	41	989 [875, 1150]	0.50
Lymph node aROI ADCmin	4	761 [607, 820]	41	799[659, 900]	0.40
Lymph node rROI ADCmean	4	888 ± 114	41	943 ± 142	0.45
Lymph node rROI ADCmin	4	803 ± 187	41	740 ± 136	0.33
Primary tumour vROI ADCmean	4	912 ± 80	34	960 ± 134	0.49
Primary tumour vROI ADCmin	4	862 ± 235	34	740 ± 136	0.56
Primary tumour aROI ADCmean	4	863 ± 74	34	918 ± 137	0.45
Primary tumour aROI ADCmin	4	691 ± 97	34	725 ± 157	0.68
Primary tumour rROI ADCmean	4	793 [737, 904]	34	806 [760, 939]	0.68
Primary tumour rROI ADCmin	4	673 ± 112	34	735 ± 171	0.49

ADC, apparent diffusion coefficient; DFS, diesease free survival; HNSCC, head and neck squamous cell carcinoma; LRFS, locoregional and disease-free survival; OPC, oropharyngeal cancer; ROI, region of interest.

Summary statistics: number (percentage), mean ± standard deviation when normally distributed and median [inter-quartile range] when not normally distributed