Table 5.

Univariate and multivariate analysis in assessing the impact of M subcategories for patients with synchronous metastatic NPC

Variable	HR	95% CI	P
Univariate analysis
Age (≥48 years/<48 years)	1.32	1.05–1.65	0.016
Sex (female/male)	0.85	0.62–1.17	0.319
UICC T category (T3–4/T1–2)	0.93	0.79–1.22	0.930
UICC N category (N1–3/N0)	1.93	1.12–3.31	0.017
KPS (< 80/≥ 80)	1.66	1.03–2.67	0.036
BMI (<18.5/≥18.5)	1.23	0.90–1.67	0.189
Radiotherapy to primary tumor (yes/no)	0.52	0.41–0.65	<0.001
Cycles of chemotherapy (>4/≤4)	0.71	0.57–0.89	0.003
M subcategorya			<0.001
M1a	Ref
M1b	1.90	1.30–2.76	0.001
M1c	3.10	2.08–4.62	<0.001
Multivariate analysis
Age (≥48 years/<4 years)	1.24	0.99–1.56	0.065
UICC N category (N1–3/N0)	1.83	1.05–3.17	0.032
Radiotherapy to primary tumor (yes/no)	0.63	0.49–0.80	<0.001
Cycles of chemotherapy (>4/≤4)	0.63	0.50–0.79	<0.001
M subcategorya			<0.001
M1a	Ref
M1b	1.69	1.16–2.48	0.007
M1c	2.64	1.75–3.98	<0.001

KPS Karnofsky performance score; BMI body mass index; Ref reference; Other abbreviations as in Table 4.

^aOne of the 505 patients with an unspecified metastatic disease cannot be classified to any of the three subcategories.