UC Irvine

374 Background: Chemoprevention with difluoromethylornithine (DFMO) plus sulindac markedly reduces risk of recurrence in colorectal adenoma (CRA) patients. Obesity is associated with risk of CRA and colorectal cancer (CRC). This study investigates how obesity influences CRA characteristics at baseline and risk of recurrence after treatment with DFMO plus sulindac vs. placebo. METHODS: Our analysis included subjects enrolled in a phase III CRA prevention clinical trial investigating DFMO plus sulindac vs. placebo. Patients were classified by obesity (BMI > 30 kg/m(2)) status at baseline. Pearson's χ(2) statistic or Fisher's exact test and Mann-Whitney U test were used to compare baseline characteristics with regard to obesity status. Log-binomial regression analysis was used to determine the relative risk of metachronous adenoma, adenoma with advanced histology, or multiple adenomas, adjusted for covariates. RESULTS: At baseline, obesity was associated with increased adenoma number (p =0.017), size (p =0.003), advanced histology (p =0.042), high-risk adenomas (p =0.0002), and distal adenomas (p =0.038). Obesity did not modify adenoma recurrence after treatment with DFMO plus sulindac or placebo (p =0.80). CONCLUSIONS: Our results provide supporting evidence for the association of obesity with high-risk adenoma features at baseline; however, obesity does not substantially modify CRA risk reduction after treatment with DFMO plus sulindac vs. placebo. [Table: see text] [Table: see text].