Predictor X_i

Coefficient b_i

Hazard Ratio

p-value

Stage IIIB

0.57

1.78

0.016

Chemotherapy Use

−0.79

0.46

0.039

Age before RT

0.04

1.04/1 year

0.012

V55Gy

0.0430

1.044/1% of volume

0.034