Table 4 Predictors of grade 2+ xerostomia at 6 months by univariate and multivariate logistic regression

Contralateral SMG dose (Gy)

1.07 (1.05-1.11)

<0.0001

1.07 (1.02-1.11)

0.002

Contralateral parotid dose (Gy)

1.10 (1.02-1.21)

0.03

0.92 (0.81-1.04)

0.19

T4 tumor

5.63 (2.21-15.31)

0.0004

3.90 (1.10-14.95)

0.04

Bilateral nodal disease

6.07 (2.26-17.85)

0.0005

2.67 (0.62-12.01)

0.19

Base of tongue primary

1.94 (0.84-4.55)

0.12

2.30 (0.71-7.95)

0.17

Concurrent systemic therapy

5.88 (1.01-111.52)

0.10

2.51 (0.33-53.76)

0.44

Age at treatment

1.03 (0.98-1.08)

0.31

1.02 (0.96-1.09)

0.56