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Table 2 Comparing FAP versus AFAP upper gastrointestinal phenotypes

From: Variables affecting penetrance of gastric and duodenal phenotype in familial adenomatous polyposis patients

Characteristics Total (n = 150) FAP (n = 79) AFAP (n = 71) p-value1
Number duodenal polyps:
 Median (25th–75th percentile) 7 (1–18) 17 (8–33) 4 (0–7) < 0.0001*
Sum diameter duodenal polyps:
 Median (25th–75th percentile) 15.5 (5–43) 32 (15–75) 7 (0–15) < 0.0001*
 Number with zero duodenal polyps 27 (18.0%) 6 (7.6%) 21 (29.6%) 0.0005
Spigelman classification: 0 27 (18.0%) 6 (7.6%) 21 (29.6%) < 0.0001*
 I 19 (12.7%) 3 (3.8%) 16 (22.5%)
30 (42.3%)
 II 81 (54%) 51 (64.6%)
 III 22 (14.7%) 18 (22.8%) 4 (5.6%)
 IV 1 (0.7%) 1 (1.3%) 0 (0%)
Number of ampullas with adenoma involvement:
 Yes 20 (13.3%) 15 (19%) 5 (7%) 0.0659
 No 97 (64.7%) 50 (63.3%) 47 (66.2%)
 Missing 33 (22%) 14 (17.7%) 19 (26.8%)
Sum diameter duodenal polyps ≥10 mm 65% (n = 97) 82% (n = 67) 44% (n = 30) < 0.0001*
Number gastric polyps:     
Median (25th–75th percentile) 72.5 (15–200) 50 (15–150) 100 (1–200) 0.6703
Patients with > 10 gastric polyps 78.0% (117) 81.0% (64) 74.7% (53) 0.3474
  1. 1Continuous variables compared with Wilcoxon rank sum test (number and sum diameter of polyps). Median and 25th–75th percentile describe the distribution of the variable within the Total, FAP and AFAP groups. Categorical values compared with chi-square test (sum diameter duodenal polyps > 10, patients > 10 gastric polyps).
  2. *When smokers or recent NSAID usage was excluded, there was no change in significant associations with FAP vs AFAP