Long-Term Outcomes Following Positive Colorectal Screening
In many settings, less than 60% of patients receive a colonoscopy within one year of a positive FOBT (fecal occult blood test) screening for colorectal cancer (CRC). Also, despite persistently low rates of follow-up colonoscopy in older adults with positive FOBT results, the long-term outcomes of screening and follow-up practices have not been described. For example, the benefit of finding asymptomatic cancer or precancerous polyps that would have caused symptoms years later must be weighed against immediate burdens of follow-up procedures and treatments stemming from a positive screening result. This longitudinal cohort study examined outcomes following a positive screening FOBT result for 212 Veterans ages 70 years or older at four VA facilities in 2001. Both Veterans who did receive a follow-up colonoscopy and Veterans who did not were followed through 2008. Investigators used chart review in addition to VA and Medicare data to assess: procedures, colonoscopy findings, cancer diagnoses, treatment outcomes, complications, and mortality.
- Over a 7-year period, a little more than half of the older Veterans in this study received a follow-up colonoscopy after a positive FOBT.
- Among Veterans who received follow-up colonoscopy, more than 25% had significant adenomas or cancer detected, were treated, and survived for more than five years.
- Approximately 59% of Veterans who received follow-up colonoscopy had no significant findings, and 10% experienced complications from colonoscopy or cancer treatment.
- Among Veterans who did not receive follow-up colonoscopy, 57% underwent some form of follow-up other than colonoscopy (e.g., repeat FOBT or sigmoidoscopy) and 59% had more than one non-colonoscopy follow-up test. Nearly half of the non-colonoscopy group died of other causes within five years, and 3% ultimately died of colorectal cancer.
- Veterans with the best predicted life expectancy were less likely to experience net burden from screening than Veterans with the worst predicted life expectancy.
- These findings support guidelines that recommend using life expectancy to guide CRC screening decisions in older adults, and argue against one-size-fits-all interventions that simply aim to increase overall screening and follow-up rates.
- The sample size was relatively small.
- Chart review used to assess patient outcomes later in the study may have missed some complications or testing done outside of VA.
This study was partly funded by HSR&D (IIR 04-427), and Dr. Kistler was supported by the VA Quality Scholars Program. Dr. Walter is part of HSR&D’s Program to Improve Care for Veterans with Complex Comorbid Conditions in San Francisco, CA.
Kistler C, Kirby K, Lee D, Casadei M, and Walter L. Long-Term Outcomes Following Positive Fecal Occult Blood Test (FOBT) Results in Older Adults: Benefits and Burdens. Archives of Internal Medicine May 9, 2011;e-pub ahead of print.