TABLE III.

Prognostic factors for locoregional control, distant disease-free survival, disease-free survival, and overall survival, as reported in the literature

Reference	Country	Pts (n)	Median follow-up (months)	Cohort characteristics (%)		Factors that significantlya,b predict ...
				Stage I/II vs. stage III/IV	5-Year overall survival	Disease-free survival	Overall survival
Fordice et al., 199110	U.S.A.	160	78	Unreported	Unreported	—	N stage Symptoms Histology Perineural invasion
Bhayani et al., 200127	U.S.A.	60	198	Unreported	Unreported	—	—
Marcinow et al., 201013	U.S.A.	87	98	53 vs. 47	Unreported	Perineural invasion Positive margin	TNM stage Site of origin Lymphovascular invasion
Balamucki et al., 201232	U.S.A.	120	103.2	41 vs. 59	68	—	T stage Perineural invasion
Shen et al., 201230	China	101	78.1	Unreported	91.7	T stage Treatment received	—
Choi et al., 201333	South Korea	88	57.1	53 vs. 47	89.7	Tumour grade N stage Adjuvant RT Diabetes mellitus	Age Diabetes mellitus
Monteiro et al., 201329	Portugal	114	90	53 vs. 47	60.5	Sex Perineural invasion	Age TNM stage Histology Perineural invasion
Van Weert et al., 20134	Netherlands	105	78.1	54 vs. 46	68	Histology T stage N stage Margin status	Histology T stage N stage Margin status
Zhang et al., 201311	China	218	63.6	59 vs. 41	Unreported	T-stage N-stage	—
Present work	Canada	60	32	60 vs. 40	64.5	TNM stage T stage N stage Treatment received Margin status	Age N stage Treatment received Margin status

^aOne-sidedp values less than 0.05 were deemed significant in all studies. Univariate and multivariate analyses were both considered.

^bHistology = solid vs. non-solid (cribriform, tubular).