Table 3 Univariate and multivariable competing risk model regression analyses of CSS in oral cavity squamous cell carcinoma

Age at diagnosis

 18–39

Reference

Reference

 40–49

1.04 (0.91–1.18)

0.590

0.98 (0.86–1.12)

0.800

 50–59

1.17 (1.04–1.32)

0.011

1.06 (0.94–1.20)

0.360

 60–69

1.37 (1.21–1.55)

< 0.001

1.21 (1.07–1.38)

0.002

 70 + 

2.05 (1.82–2.32)

< 0.001

1.85 (1.63–2.10)

< 0.001

Sex

 Female

Reference

Reference

 Male

0.84 (0.81–0.88)

< 0.001

0.85 (0.81–0.89)

< 0.001

Marital status

 Married

Reference

Reference

 Unmarried

1.71 (1.65–1.78)

< 0.001

1.33 (1.27–1.38)

< 0.001

Race

 White

Reference

Reference

 Black

1.86 (1.76–1.97)

 < 0.001

1.29 (1.20–1.38)

< 0.001

 Asian or Pacific Islander

1.08 (0.99–1.18)

0.072

1.18 (1.08–1.29)

< 0.001

 American Indian/Alaska Native

1.11 (0.86–1.42)

0.430

1.06 (0.82–1.36)

0.650

Location

 Floor of mouth

Reference

Reference

 Other mouth

0.64 (0.60–0.69)

< 0.001

0.60 (0.55–0.64)

< 0.001

 Tongue

0.72 (0.68–0.77)

< 0.001

0.76 (0.71–0.82)

< 0.001

Size

 < 1

Reference

Reference

 < 2

1.65 (1.45–1.88)

< 0.001

1.51 (1.33–1.72)

< 0.001

 < 3

2.49 (2.20–2.82)

< 0.001

1.83 (1.57–2.12)

< 0.001

 < 4

3.21 (2.84–3.64)

< 0.001

2.11 (1.80–2.47)

< 0.001

 < 5

4.56 (4.02–5.17)

< 0.001

2.59 (2.20–3.05)

< 0.001

 ≥ 5

7.37 (6.51–8.34)

< 0.001

3.39 (2.87–4.00)

< 0.001

 Unknown

4.46 (3.94–5.06)

< 0.001

2.73 (2.29–3.25)

< 0.001

Treatment

 No/unknown

Reference

Reference

 Surgery

0.163 (0.15–0.18)

< 0.001

0.33 (0.29–0.37)

< 0.001

 Radiation

0.441 (0.40–0.49)

< 0.001

0.53 (0.47–0.59)

< 0.001

 Chemotherapy + XRT

0.28 (0.26–0.30)

< 0.001

0.33 (0.30–0.36)

< 0.001

 Surgery + XRT

0.23 (0.21–0.25)

< 0.001

0.35 (0.32–0.39)

< 0.001

 Triple therapy

0.23 (0.21–0.25)

< 0.001

0.34 (0.31–0.38)

< 0.001

 Others

0.74 (0.66–0.83)

< 0.001

0.65 (0.57–0.75)

< 0.001

Grade

 Well-differentiated

Reference

Reference

 Moderately differentiated

1.28 (1.21–1.36)

< 0.001

1.08 (1.01–1.16)

0.023

 Poorly differentiated

1.05 (0.99–1.12)

0.130

0.86 (0.80–0.93)

< 0.001

 Undifferentiated

0.87 (0.69–1.11)

0.260

0.69 (0.54–0.88)

0.003

T classification

 T1

Reference

Reference

 T2

1.80 (1.70–1.92)

< 0.001

1.17 (1.06–1.30)

0.002

 T3

3.09 (2.89–3.30)

< 0.001

1.29 (1.15–1.45)

< 0.001

 T4

4.48 (4.23–4.75)

< 0.001

1.94 (1.74–2.16)

< 0.001

 Unknown

2.18 (2.01–2.36)

< 0.001

0.85 (0.73–0.98)

0.025

N classification

 N0

Reference

Reference

 N1

1.52 (1.43–1.60)

< 0.001

1.48 (1.39–1.58)

< 0.001

 N2

1.63 (1.55–1.70)

< 0.001

1.56 (1.47–1.65)

< 0.001

 N3

2.34 (2.14–2.57)

< 0.001

2.06 (1.84–2.31)

< 0.001

 Unknown

2.87 (2.46–3.35)

< 0.001

1.50 (1.26–1.79)

< 0.001

M classification

 M0

Reference

Reference

 M1

4.39 (4.05–4.76)

< 0.001

2.62 (2.36–2.90)

< 0.001

 Unknown

2.60 (2.11–3.22)

< 0.001

1.47 (1.12–1.93)

0.006