Do older adults using NSAIDs have a reduced risk of colorectal cancer?

Background and objectives: Colorectal cancer (CRC) is primarily a disease of older adults. Although NSAIDs are thought to protect from CRC, and long-term use of NSAIDs is common in the elderly, little is known about the impact of NSAID use on CRC risk at advanced age. We specifically reviewed current evidence regarding the effects of NSAIDs on CRC risk in individuals aged >= 65 years, a rapidly growing age group. Study design: We searched all articles in PubMed published before August 2005. Studies were included if a subgroup analysis of older adults (>= 65 years of age) was performed, or if long-term use of NSAIDs for >= 5 years and CRC risk was investigated. From the selected studies, relevant information, including sample characteristics and association with CRC risk, was extracted and compared. Results: Altogether 19 studies were identified. Only four studies specifically considered NSAID use in people >= 65 years of age; of these, two showed risk reduction for CRC comparable to that seen in younger age groups or in all age groups. The most informative observational studies found decreasing relative risk of CRC with increasing duration of NSAID use, suggesting substantial risk reduction after 10-20 years of regular use. Conclusions: The available data on long-term effects of NSAID use in elderly people are sparse but predominantly indicate risk reduction for CRC comparable to that seen in younger age groups or all ages. Whether and to what degree initiating NSAID use in old age prevents CRC is essentially unknown. In light of the potential adverse effects of NSAIDs, including recent data on adverse cardiovascular outcomes, more information is needed on the minimum effective dose of NSAIDs and the duration of use required in order to evaluate individual risks and benefits in older adults.