Table 3. Predicted probability of nodal metastasis when depth is dichotomised as <4mm and 4+mm.

Size of the Tumour (T)		Buccal mucosa			Tongue
		POI 2	POI 3	POI 4	POI 2	POI 3	POI 4
T1	depth <4mm	0.01	0.02	0.05	0.03	0.05	0.11
	depth 4+ mm	0.02	0.03	0.07	0.04	0.07	0.15
T2	depth <4mm	0.04	0.06	0.13	0.08	0.13	0.27
	depth 4+ mm	0.05	0.08	0.18	0.12	0.18	0.34
T3	depth <4mm	0.12	0.18	0.34	0.24	0.34	0.55
	depth 4+ mm	0.16	0.24	0.43	0.31	0.43	0.64
T4	depth <4mm	0.14	0.21	0.39	0.28	0.39	0.60
	depth 4+ mm	0.19	0.28	0.48	0.36	0.48	0.69

POI- pattern of invasion, T- size of the tumour. Colour codes: white = probability is <0.10 (low risk), yellow = probability between 0.10 and 0.17 (minor risk), blue = probability between 0.18 and 0.24 (moderate risk), pink = probability between 0.25 and 0.34 (high risk), red = probability 0.35 or higher (severe risk).