Table 2 Primary study outcome and associated factors of TLN in Cox regression models

Primary analysis

Occurrence of TLN

11 (5.6)

1 (0.4)

< 0.01^#

Multi-variable analysis

Cancer type (NPC vs. non-NPC)

13.35 (1.37, 130.61)

0.03^†

Age

1.04 (0.98, 1.11)

0.16

T3/T4 stage

3.27 (0.80, 13.27)

0.10

Radiation doses

1.00 (1.00, 1.00)

0.01

Proton-beam therapy

1.67 (0.40, 6.94)

0.48

Re-irradiation

0.87 (0.04, 19.60)

0.93

Time to radiation therapy

1.00 (0.95, 1.05)

0.96