Table 3. Univariate analysis of association between genotypes and RR, TTP, and OS.

Genotype	No. (%)	RR (%)	P-valuea	OR (95% CI)	P-value	TTP (months) (95% CI)	P-valuea	HR (95% CI)	P-value	OS (months) (95% CI)	P-valuea	HR (95% CI)	P-value
CYP2A6			0.008				0.021				0.004
W/W	28 (26)	66.7		1 (reference)		7.2 (2.7–11.7)		1 (reference)		23.2 (16.3–30.1)		1 (reference)
W/V other than *1/*4	48 (44)	58.3		0.699 (0.262–1.873)	0.478	6.1 (4.6–7.6)		1.168 (0.689–1.978)	0.565	15.4 (12.0–18.8)		1.759 (0.884–3.500)	0.108
V/V or *1/*4	32 (30)	32.3		0.238 (0.079–0.714)	0.010	3.5 (2.3–4.7)		2.059 (1.130–3.751)	0.018	12.0 (8.2–15.8)		2.836 (1.350–5.957)	0.006
ERCC1 8525C>T			0.657				0.200				0.530
C/C	64 (59)	54.0		1 (reference)		6.7 (5.5–7.9)		1 (reference)		17.9 (11.2–24.6)		1 (reference)
T/C	37 (34)	52.8		0.953 (0.420–2.164)	0.909	4.8 (3.1–6.5)		1.144 (0.732–1.788)	0.556	15.5 (13.3–17.7)		0.940 (0.556–1.587)	0.816
T/T	7 (6)	42.9		0.640 (0.132–3.096)	0.579	3.6 (3.2–4.0)		1.916 (0.810–4.532)	0.139	6.6 (6.0–7.2)		1.918 (0.748–4.919)	0.175
ERCC1 19442C>A			0.048				0.012				0.109
A/A	8 (7)	87.5		1 (reference)		7.9 (4.9–10.9)		1 (reference)		24.3 (5.2–43.4)		1 (reference)
C/A	38 (35)	55.3		0.176 (0.020–1.577)	0.121	7.6 (5.6–9.6)		1.804 (0.691–4.710)	0.228	18.1 (13.9–22.3)		1.829 (0.608–5.504)	0.283
C/C	62 (57)	46.7		0.125 (0.014–1.080)	0.059	4.4 (3.2–5.6)		2.648 (1.050–6.675)	0.039	13.5 (11.0–16.0)		2.242 (0.793–6.338)	0.128
XRCC1 1196G>A			0.947				0.489				0.683
G/G	49 (45)	51.1		1 (reference)		6.0 (4.3–7.7)		1 (reference)		15.1 (10.8–19.4)		1 (reference)
G/A	38 (35)	57.9		1.317 (0.557–3.115)	0.530	6.1 (3.8–8.4)		0.863 (0.546–1.364)	0.528	15.4 (11.9–18.9)		1.137 (0.681–1.897)	0.623
A/A	21 (19)	47.6		0.871 (0.311–2.439)	0.793	4.8 (1.9–7.7)		0.829 (0.431–1.597)	0.576	NR		0.532 (0.159–1.776)	0.305
No. of risk genotypes of CYP2A6 and ERCC1 19442C>Ab			0.004				0.0005				0.007
0	33 (31)	63.6		1 (reference)		7.6 (6.0–9.2)		1 (reference)		21.2 (16.1–26.3)		1 (reference)
1	56 (52)	58.2		0.795 (0.327–1.934)	0.613	5.0 (3.0–7.0)		1.391 (0.856–2.261)	0.182	15.0 (11.8–18.2)		1.432 (0.782–2.619)	0.245
2	19 (18)	16.7		0.114 (0.027–0.477)	0.003	3.2 (2.4–4.0)		3.693 (1.924–7.088)	0.00008	7.7 (0–15.7)		3.067 (1.424–6.604)	0.004

Abbreviations: HR=Hazards ratio; OR=odds ratio; OS=overall survival; RR=response rate; TTP=time to progression; V=variant allele that abolishes or reduces CYP2A6 activity (*4, *7, *9, and *10); W=wild-type allele of CYP2A6 (*1).

^aTrend test.

^bAt-risk genotypes: V/V or 1/*4 for CYP2A6 and C/C for ERCC1 19442C>A.