Second primary malignancy risk after radiotherapy in rectal cancer survivors

Table 3 Cox regression of second primary malignancy

	Univariate Cox regression		Multi-variate Cox regression
	Hazard ratio (95%CI)	P value	Hazard ratio (95%CI)	P value
Sex(M)	1.57 (1.40-1.75)a	< 0.001	1.47 (1.32-1.65)a	< 0.001
Diagnosis age (1 yr increment)	1.02 (1.01-1.02)a	< 0.001	1.02 (1.01-1.02)a	< 0.001
Diagnosis year	1.06 (1.04-1.08)a	< 0.001	1.06 (1.04-1.08)a	< 0.001
Chemotherapy	0.95 (0.86-1.06)	0.371	0.97 (0.87-1.08)	0.562
DM	1.11 (0.99-1.23)	0.062	1.14 (1.02-1.28)a	0.027
Hypertension	1.01 (0.90-1.13)	0.849	0.86 (0.75-0.97)a	0.017
Liver cirrhosis	2.47 (2.10-2.90)a	< 0.001	2.40 (2.03-2.82)a	< 0.001
Rheumatologic disease	0.78 (0.62-0.99)a	0.038	0.81 (0.64-1.03)	0.080
End stage renal disease	1.01 (0.89-1.16)	0.828	0.91 (0.80-1.05)	0.192
COPD	1.33 (1.20-1.48)a	< 0.001	1.19 (1.06-1.33)a	0.003
Dyslipidemia	0.87 (0.78-0.96)a	0.008	0.85 (0.76-0.95)a	0.006
Radiotherapy1	1.04 (0.90-1.19)	0.625	1.05 (0.91-1.21)	0.494
Long course RT1	1.25 (0.97-1.62)	0.090	1.28 (0.98-1.67)2	0.071
Short course RT1	1.01 (0.56-1.83)	0.976	0.91 (0.50-1.64)2	0.742
Post-OP RT1	0.98 (0.84-1.15)	0.801	1.01 (0.86-1.18)2	0.941

¹Indicates surgery-only as reference;

²Indicates calculated separately with “Radiotherapy” using same model.

^aP < 0.05. DM: Diabetes mellitus; COPD: Chronic obstructive pulmonary disease; Post-OP: Postoperative.