From: Incidence of pneumonia and risk factors among patients with head and neck cancer undergoing radiotherapy
Treatment
n
Cases
OR*
(95% CI)
  RT alone
6397
336
1.00
(reference)
  Neck lymph node dissection plus RT
1915
72
0.75
(0.58~0.98)
  CCRT alone
5961
303
1.12
(0.95~1.32)
  Neck lymph node dissection plus CCRT
1274
51
0.88
(0.65~1.20)