Table 3. Calculation of the risk score and the C-N model for progression-free survival of the LSCC patients.

Characteristic	N = ln HR	Score
N stage
N0		0
N1	0.673	2
N2	1.108	3
CISD2 High vs Low	1.199	3
Low risk group		0
Middle risk group		2–3
High risk group		5–6

Abbreviations: LSCC, laryngeal Squamous cell carcinoma (LSCC); CISD2, CDGSH iron sulfur domain2; C-N model, CISD2 plus N stage model; HR, Hazard ratio