Table 3.

Estimated model coefficients for Mayo Clinic and TREAT models

	Mayo Coefficienta	TREAT Coefficienta	TREAT Odds Ratio (95%CI)	p-value
Constant	−6.827	−4.715
Age(per year)	0.0391	0.0533	1.05(1.03, 1.08)	<0.001
BMI	-	−0.0262	0.97(0.93, 1.02)	0.24
Gender-Male	-	−0.0547	0.95(0.55, 1.64)	0.84
Pack-years	-	a	b	0.02
Smoking History (yes/no)	0.792	-	-	-
Lesion Size(per mm)	0.127	0.0577	1.06(1.04, 1.08)	<0.001
Spiculated lesion edge	1.041	0.277	1.32(0.73, 2.40)	0.26
Lesion location–upper lobe	0.784	−0.015	1.02(0.58, 1.78)	0.99
Lesion Growth
No lesion growth	-	Reference	Reference	-
Insufficient data	-	0.259	1.29(0.56, 2.79)	0.59
Growth observed	-	1.160	3.18(1.58, 6.39)	0.003
Previous cancer	1.339	0.639	1.89(1.05, 3.42)	0.03
Predicted FEV1	-	-0.013	0.99(0.97, 1.00)	0.07
Any pre-opsymptoms	-	-0.461	0.63(0.33, 1.20)	0.16
FDG-PET Avid	-	1.834	6.26(2.78, 14.1)	<0.001

^aProbability {lung cancer=1} =e^x/(1+e^x); where X= −4.715 + 0.0533*(Age) – 0.0262*(BMI) − 0.0547*(Gender: Male) + 0.02338*(Pack-years) – − 0.000003* ${(\text{Pack-years})}_{+}^3+0.000006*{(\text{Pack-years}-36)}_{+}^3+0.000003*{(\text{Pack-years}-80)}_{+}^3+0.0577*$ (Lesion Size) + 0.277*(Speculated lesion) + 0.015*(Lesion location) + 0.259*{Lesion Growth: Insufficient data} + 1.160*{Lesion Growth: Growth observed} + 0.639*(Previous cancer) – 0.013*(Predicted FEV₁) – 0.461*(Any symptoms) + 1.834*(FDG-PED Avid) and {c}=1 if subject is in categoryc, 0 otherwise; ${(\text{Pack-years}-\mathrm{x})}_{+}^3={(\text{Pack-year}-\mathrm{x})}^3\text{if}{(\text{Pack-years}-\mathrm{x})}^3>0$, 0 otherwise.

^bPack-years is modeled as a restricted cubic spline and therefore odds ratios are not directly interpretable.