Table 2.

Univariable Cox regression analyses for the volumes of interest of MTV

	Overall survival			Disease-free survival
	HR (95% CI)ª	p-value	C-index	HR (95% CI)ª	p-value	C-index
T MTV with SUV2.5 threshold	1.02 (1.01–1.03)	0.009	0.656	1.02 (1.01–1.03)	0.002	0.695
N MTV with SUV2.5 threshold	1.01 (1.003–1.027)	0.013	0.586	1.01 (1.003–1.02)	0.012	0.587
T + N with MTV SUV2.5 threshold	1.01 (1.01–1.02)	0.002	0.667	1.01 (1.01–1.02)	< 0.001	0.703
T MTV with background-level threshold	1.02 (1.01–1.04)	0.005	0.659	1.03 (1.01–1.0)	0.001	0.688
N MTV with background-level threshold	1.02 (1.004–1.04)	0.011	0.575	1.01 (1.002–1.03)	0.025	0.574
T + N MTV with background-level threshold	1.02 (1.01–1.03)	0.002	0.656	1.02 (1.01–1.03)	< 0.001	0.681

ªPer unit increment

HR hazard ratio, CI confidence interval, MTV metabolic tumor volume, C-index Harrell’s C-index, SUV standardized uptake value, T tumor, N lymph node