Are Serum Salicylate Levels Associated with Risk of Colorectal Adenomas?

Abstract

Purpose: Colorectal adenomas are pre-invasive neoplasms that are important targets for chemoprevention. Intake of aspirin is associated with reduction in risk of colorectal adenoma and carcinoma. Some plants contain salicylates, and individuals not taking aspirin may have measurable salicylate levels. It has been proposed that the salicylates in plants may have chemopreventive effects. However, the association between serum salicylate level and recurrence of adenoma has not been studied, particularly in subjects not taking aspirin. Methods: We measured serum salicylate levels in participants of a randomized controlled trial with calcium supplementation. The endpoint was recurrence of adenomas at 4 years. Results: As expected, serum salicylate levels were higher among individuals that reported regular use of aspirin. In generalized regression models, there was no association between serum SA and risk of adenoma or advanced adenoma over the next three years in crude or adjusted models (RR per standard deviation = 1.00 (95% CI 0.97- 1.03) and 1.04 (95% CI 1.00- 1.08) for all adenomas and advanced adenomas. There was no interaction between calcium supplementation and serum SA levels on risk of adenoma or advanced adenoma (p for interaction 0.78 and 0.87 for all adenomas and advanced adenomas respectively). Conclusion: Serum salicylate levels are not associated with risk of recurrence of adenomas and do not appear to modify the effect of calcium supplementation in preventing recurrent colorectal adenomas.