Table 1

Levels of IGF-I,a IGFBP-3 and IGF-I/IGFBP-3 molar ratio in SPT patients and controls

All P values are two-sided, and associations are considered statistically significant at P < 0.05.

VariablesControls (n = 173)SPTs
Total (n = 80)Smoking-relatedb (n = 58)
Age (yr)
 Median (range)66 (39–85)66.5 (38–82)66.5 (38–81)
P valuec0.4930.866
Gender
 Male34 (19.7%)16 (20.0%)12 (20.7%)
 Female139 (80.4%)64 (80.0%)46 (79.3%)
P valued0.9490.864
Smoking status
 Never24 (13.9%)6 (7.5%)4 (6.9%)
 Former100 (57.8%)37 (46.3%)26 (44.8%)
 Current49 (28.3%)37 (46.3%)28 (48.3%)
P valued0.0150.016
Treatment regimen
 Placebo88 (50.9%)46 (57.5%)35 (60.3%)
 13 cRA85 (49.1%)34 (42.5%)23 (39.7%)
P valued0.3260.211
IGF-I ng/ml
 Median (range)93.61 (17.19–352.33)134.85 (20.14–422.27)137.97 (20.14–422.27)
P valuec0.0010.002
IGFBP-3 ng/ml
 Median (range)2405.8 (256.8–6421.6)2969.6 (708.6–5538.6)2999.2 (708.6–5538.6)
P valuec0.0190.004
IGF-I/IGFBP-3 molar ratio
 Median (range)0.15 (0.02–0.83)0.17 (0.02–1.09)0.16 (0.02–1.09)
P Valuec0.0440.224
  • a IGF-I, insulin-like growth factor-I; IGFBP-3, IGF-binding protein-3; SPT, second primary tumors; 13 cRA, 13-cis-retinoic acid.

  • b Smoking-related SPTs include larynx, oral cavity, pharynx, lung, and bladder tumors.

  • c Kruskal-Wallis test was used to calculate the P value.

  • d χ2 test was used to calculate the P value.