Table 2.

Association between selected characteristics and Ki-ras mutation prevalence

CharacteristicsKi-ras mutations, no. (%)No Ki-ras mutations, no.Unadjusted OR (95% CI)Adjusted OR (95% CI)*P
Age (y)
    ≤6025 (10)2251.001.00<0.0001
    61-6727 (13.6)1971.23 (0.69-2.20)1.26 (0.68-2.31)
    68-7231 (14.7)1801.55 (0.88-2.72)1.29 (0.71-2.35)
    >7249 (23.0)1642.69 (1.60-4.53)2.62 (1.50-4.55)
Gender
    Female44 (15.1)2481.000.64
    Male88 (14.5)5180.96 (0.65-1.42)0.90 (0.59-1.38)
Family history
    No112 (15.0)6331.001.000.45
    Yes20 (13.1)1330.85 (0.51-1.42)0.80 (0.45-1.42)
Previous polyp
    No84 (16.4)4271.001.000.11
    Yes32 (10.5)2740.59 (0.38-0.92)0.68 (0.42-1.10)
No. of adenomas at baseline
    171 (13.9)4401.001.000.65
    230 (14.6)1761.06 (0.67-1.68)0.95 (0.57-1.57)
    >231 (17.1)1501.28 (0.81-2.03)1.16 (0.70-1.92)
Adenoma location
    Distal colon60 (13.7)3771.001.000.03
    Proximal colon32 (10.9)2610.77 (0.49-1.22)0.87 (0.52-1.46)
    Rectum19 (22.6)651.84 (1.03-3.28)2.05 (1.09-3.88)
Size (cm)
    <156 (10.2)4911.001.000.33
    ≥175 (21.5)2742.40 (1.65-3.50)1.24 (0.80-1.93)
Dysplasia
    Low grade74 (11.0)6011.001.000.07
    High grade53 (25.2)1572.74 (1.85-4.07)1.53 (0.97-2.41)
Histology
    Tubular53 (8.1)6041.001.00<0.0001
    Tubulovillous66 (31.7)1425.30 (3.53-7.94)4.19 (2.62-6.68)
    Villous12 (40.0)187.60 (3.47-16.62)5.45 (2.28-13.03)
Advanced adenomas§
    No28 (6.5)4011.001.00<0.0001
    Yes104 (28.2)3654.08 (2.63-6.34)3.96 (2.54-6.18)
  • * Advanced adenoma ORs were adjusted for age; all other factors were adjusted for age, adenoma size, histology, and HGD.

  • History of colorectal cancer in one or more first-degree relatives.

  • Self-reported history of a polyp prior to baseline adenoma.

  • § Includes one or more of the following characteristics: tubulovillous or villous histology, ≥1 cm in size, or HGD.