Effect of the non-steroidal anti-inflammatory drug sulindac on colorectal adenomas of uncolectomized familial adenomatous polyposis

Background: The aim of the present study was to elucidate the effect of sulindac on uncolectomized familial adenomatous polyposis (FAP). Methods: Seven FAP patients (SU group) without proctocolectomy were given sulindac 300 mg/day orally for 12 months. Six FAP patients without sulindac (non‐SU group) served as controls. Colorectal lesions were assessed by protrusion index (no. radiolucent areas/cm²; PI) under barium enema examination and non‐polypoid lesion were assessed under chromoscopy prior to and at the end of the observation period. In the SU group, germline adenomatous polyposis coli (APC) mutation was determined by protein truncation test. Results: In the SU group, PI decreased significantly in the distal colon (from 3.0 ± 1.1 to 1.1 ± 0.8/cm², P < 0.02) and in the proximal colon (from 3.4 ± 2.4 to 0.9 ± 1.3/cm², P < 0.02). The PI in the non‐SU group slightly but significantly increased in the distal colon (from 1.0 ± 0.8 to 1.2 ± 0.9/cm²; P < 0.05) and it remained unchanged in the proximal colon (from 0.6 ± 0.3 to 0.7 ± 0.3/cm²; P > 0.05). Chromoscopy at the end of observation identified non‐polypoid lesions in five patients in the SU group, whereas such lesions were not found in the non‐SU group (71% vs 0%, P = 0.016). Decrease in PI was not different among distal APC mutation (exons 1–9), proximal APC mutation (exons 10–15) and negative mutation. Conclusion: Sulindac reduces colorectal adenomas of protruding type in uncolectomized FAP. The effect of sulindac may be unrelated to genotype of FAP.