Table 1:

Matched features of tumors that recurred (cases) vs. non-recurrent tumors (controls)

Variable	Categories	Case (n=50)	Control (n=50*)	P-value
Overall pathologic stage	Stage I	25	25	1.000
	Stage II	25	25
Pathologic T-stage	pT0	1	0	.483
	pT1	11	15
	pT2	32	28
	pT3	6	7
Pathologic N-stage	pN0	5	5	.977
	pN1	26	27
	pN2	19	18
Treatment	Surgery	4	4	1.000
	Surgery + RT	19	19
	Surgery + CRT	27	27
Systemic agent	Cisplatin	21	23	.848
	Cetuximab	5	3
	Carboplatin/Taxol	1	1
Smoking history	≤10 pack-years	34	33	.832
	>10 pack-years	16	17

RT=radiation therapy, CRT=chemoradiation, P-values are from Fisher-exact test. Freeman-Holton extension was used for more than two categories.

^*Comparison includes duplication of one control as a match for two cases