Table 2 Univariate logistic regression analysis of RIS in 190 NPC patients without sinusitis before RT

Time (months post-RT for NPC)

0.012

3 months after RT

0.025

0.318

0.117 ~ 0.865

6 months after RT

0.052

0.367

0.134 ~ 1.009

9 months after RT

0.455

0.662

0.225 ~ 1.953

12 months after RT

0.296

0.551

0.181 ~ 1.684

18 months after RT

0.878

1.100

0.324 ~ 3.738

24months after RT

0.787

1.192

0.333 ~ 4.269

Age

0.703

0.914

0.578 ~ 1.447

Gender

0.141

0.701

0.437 ~ 1.125

Pathological type

0.271

0.538

0.179 ~ 1.621

T-staging

0.306

T2

0.557

1.221

0.627 ~ 2.377

T3

0.386

1.353

0.683 ~ 2.680

T4

0.380

0.689

0.300 ~ 1.584

 N-staging

0.229

N2

0.241

1.641

0.717 ~ 3.759

N3

0.982

1.008

0.497 ~ 2.044

N4

0.513

0.770

0.352 ~ 1.686

M-staging

0.114

0.526

0.237 ~ 1.167

TNM staging

0.085

II

0.591

1.439

0.381 ~ 5.432

III

0.474

1.584

0.449 ~ 5.592

IV

0.788

0.841

0.238 ~ 2.969

Smoking history

0.000

2.806

1.651 ~ 4.771

Intranasal medication

0.735

0.925

0.590 ~ 1.452

Nasal irrigation

0.178

0.253

0.034 ~ 1.873

Radiotherapy modality

0.279

1.282

0.818 ~ 2.011

Dose of primary lesions

0.491

1.263

0.650 ~ 2.452

Chemotherapy modality

0.480

Concurrent chemotherapy

0.492

0.476

0.057 ~ 3.957

Induction & concurrent chemotherapy

0.828

0.795

0.101 ~ 6.277

Induction & concurrent & adjuvant/consolidation chemotherapy

0.762

0.726

0.091 ~ 5.773

Nasal cavity/paranasal sinus invasion

0.816

1.095

0.509 ~ 2.357