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Table 2 Univariable and Multivariable Cox Regression Analysis of Predictors for Local Failure

From: Outcomes of stereotactic body radiotherapy 60 Gy in 8 fractions when prioritizing organs at risk for central and ultracentral lung tumors

Variables

Univariable Analysis

Multivariable Analysis

HR (95.0% CI)

p-value

HR (95.0% CI)

p-value

Age at SBRT completiond

0.996 (0.938–1.057)

0.889

  

Gender

 Male

Reference

   

 Female

1.483 (0.389–5.662)

0.564

  

ECOG performance status

 0–1

Reference

   

 2–3

1.157 (0.329–4.069)

0.820

  

Age-adjusted Charlson comorbidity index d

1.003 (0.726–1.387)

0.983

  

COPD

 No COPD

Reference

   

 GOLD stage 1–2

1.198 (0.318–4.510)

0.789

  

 GOLD stage 3–4

0.785 (0.140–4.409)

0.783

  

Smoking status

 Active smoker

Reference

   

 Past smoker

0.688 (0.184–2.575)

0.579

  

 Never smoker

0.598 (0.109–3.292)

0.555

  

Tumor location

 Central

Reference

   

 Ultracentral

0.757 (0.217–2.642)

0.663

  

Tumor type

 Primary lung tumor

Reference

   

 Metastasis

0.759 (0.163–3.536)

0.726

  

ITV volume (cc) d

1.049 (1.025–1.074)

< 0.001

1.047 (1.020–1.076)

0.001

ITV Dmin a, d

1.009 (0.974–1.046)

0.607

  

ITV Dmax a, d

1.059 (0.969–1.158)

0.205

  

ITV Dmean a d

1.025 (0.950–1.106)

0.527

  

ITV V 60 Gy b, d

1.037 (0.953–1.128)

0.396

  

ITV D 99% a, d

1.003 (0.965–1.043)

0.876

  

ITV D 1% a, d

1.044 (0.956–1.141)

0.333

  

ITV volume receiving < 60 Gy (cc) d

1.063 (0.894–1.264)

0.488

  

PTV volume (cc) d, e

1.029 (1.014–1.044)

< 0.001

  

PTV Dmin a, d

1.003 (0.968–1.040)

0.863

  

PTV Dmax a, d

1.053 (0.961–1.154)

0.266

  

PTV Dmean a, d

1.037 (0.934–1.151)

0.492

  

PTV V 60 Gy c, d

1.010 (0.968–1.055)

0.633

  

PTV D 99% a, d

1.006 (0.960–1.054)

0.795

  

PTV D 1% a, d

1.042 (0.950–1.143)

0.378

  

PTV volume receiving < 60 Gy (cc) d

1.044 (1.008–1.081)

0.017

1.006 (0.956–1.058)

0.819

  1. Abbreviations: HR hazard ratio, CI confidence interval, SBRT stereotactic body radiotherapy, COPD chronic obstructive pulmonary disease, GOLD global initiative for chronic obstructive lung disease, ITV internal target volume, Dmin minimum point dose, Dmax maximum point dose, Dmean mean dose, V 60 Gy volume receiving at least 60 Gy, D 99% maximum dose covering 99% of the volume, D 1% maximum dose covering 1% of the volume, PTV planning target volume
  2. aPercentage (%) of the prescription dose of 60 Gy
  3. bPercentage (%) of the total ITV volume
  4. cPercentage (%) of the total PTV volume
  5. dAnalysis done using continuous variables
  6. ePTV volume (cc) was not included in the multivariable analysis due to collinearity with ITV volume (cc)