Table 2 Disease-specific survival analysis of the prognostic significance of single cell invasion, nuclear diameter and clinicopathologic characteristics of early oral tongue cancer (n = 311 patients)

Age

≤ 60 years

Reference

Reference

> 60 years

1.867 (1.096–3.182), P = 0.022

2.158 (1.233–3.775), P = 0.007

Gender

Male

Reference

Reference

Female

1.215 (0.740–1.992), P = 0.441

1.244 (0.738–2.095), P = 0.412

Stage

T1N0M0

Reference

Reference

T2N0M0

1.484 (0.866–2.542), P = 0.151

1.442 (0.822–2.530), P = 0.202

Differentiation (Grade)

Grade I

Reference

Reference

Grade II

1.681 (0.919–3.074), P = 0.092

2.094 (1.138–3.851), P = 0.018

Grade III

1.580 (0.790–3.159), P = 0.196

2.044 (0.996–4.196), P = 0.051

Perineural invasion

None

Reference

Reference

Yes

1.269 (0.645–2.495), P = 0.490

0.816 (0.403–1.653), P = 0.572

Depth of invasion

5 mm or less

Reference

Reference

More than 5 mm

3.042 (1.802–5.137), P < 0.001

3.056 (1.779–5.250), P < 0.001

Single cell invasion

Absent

Reference

Reference

Present

2.025 (1.217–3.368), P = 0.007

2.089 (1.224–3.566), P = 0.007

Nuclear diameter

Small

Reference

Reference

Large

1.979 (1.190–3.292), P = 0.009

2.070 (1.216–3.523), P = 0.007