Table 2.

Disease–specific survival in patients with high-grade salivary gland cancers (n = 124)

Factors (Number)	Univariate model			Multivariate model #1			Multivariate model #2
	HR	95% CI	P	HR	95% CI	P	HR	95% CI	P
Age (years)	1.021	0.994–1.049	0.135
Gender (Male/Female) (95/29)	1.446	0.636–3.290	0.379
Primary site
Parotid gland (84)	1 (Ref.)
Non-parotid gland (40)	1.246	0.640–2.427	0.518
TNM categories
T3–4/T1–2 (60/64)	1.880	0.980–3.608	0.058	0.824	0.412–1.648	0.584	1.145	0.593–2.212	0.687
N1–3/N0 (61/63)	5.573	2.651–11.713	< 0.001	8.669	3.787–19.842	< 0.001	5.632	2.638–12.027	< 0.001
M1/M0 (15/109)	4.550	2.139–9.680	< 0.001				4.591	2.100–10.035	< 0.001
Pathological diagnosis
Salivary duct carcinoma (74)	1 (Ref.)
Squamous cell carcinoma, primary (13)	1.271	0.480–3.368	0.629
Adenoid cystic carcinoma, solid type (12)	1.422	0.537–3.766	0.479
Mucoepidermoid carcinoma, high-grade (9)	1.094	0.326–3.673	0.885
Adenocarcinoma, high-grade (6)	0.386	0.052–2.870	0.352
Others* (10)	1.681	0.501–5.642	0.440
Treatment modalities
Surgery (13)	1 (Ref)			1 (Ref.)
Surgery + radiation (62)	1.247	0.372–4.182	0.721	0.761	0.216–2.678	0.671
Surgery + radiation + chemotherapy (28)	0.418	0.084–2.075	0.286	0.134	0.025–0.709	0.018
Others† (21)	4.589	1.281–16.434	0.019	2.786	0.731–10.617	0.133

M1 status was significantly associated with the application of the so-called other treatment modalities (initial non-surgical, chemotherapy or palliative treatments); thus, we built two separate multivariate models using independent variables

Abbreviation:

HR Hazard ratio, CI Confidence interval

Others^*: Atypical high-grade carcinoma, high-grade carcino-sarcoma, poorly differentiated carcinoma

Others^†: Initial non-surgical local treatment (radiation or chemoradiation), chemotherapy or palliative treatment