Table 1.

Incidence of distant metastases based on primary site.

Primary site	Incidence of distant metastasis	%
Tongue	19/516	3.7
Floor of the mouth	1/45	2.2
Upper gingiva	3/87	3.4
Lower gingiva	3/124	2.4
PIOC of the mandible	4/16	25.0
Buccal mucosa	6/90	6.7
Hard palate	0/9	0.0
Total	36/887	4.1

PIOC, primary intraosseous carcinoma.