The fecal immunochemical test is commonly used for colorectal cancer screening and positive test results require follow-up colonoscopy.
However, follow-up intervals vary, which may result in neoplastic progression.
Dr Douglas Corley and colleagues evaluated time to colonoscopy after a positive fecal immunochemical test result, and its association with risk of colorectal cancer and advanced-stage disease at diagnosis.
The research team performed a retrospective cohort study within Kaiser Permanente Northern and Southern California.
Participants were 70,124 patients aged 50 through 70 years eligible for colorectal cancer screening with a positive fecal immunochemical test result who had a follow-up colonoscopy.
|Risks were higher for examinations at 10 to 12 months for any colorectal cancer|
|Journal of the American Medical Association|
The team evaluated days to colonoscopy after a positive fecal immunochemical test result.
The researchers' main outcomes included risk of any colorectal cancer and advanced-stage disease.
Of the 70,124 patients with positive fecal immunochemical test results, the team identified 2191 cases of any colorectal cancer, and 601 cases of advanced-stage disease diagnosed.
The research team found that, compared with colonoscopy follow-up within 8 to 30 days, there were no significant differences between follow-up at 2 months, 3 months, 4 to 6 months, or 7 to 9 months for risk of any colorectal cancer or advanced-stage disease.
The team observed that risks were significantly higher for examinations at 10 to 12 months for any colorectal cancer, and advanced-stage disease, and more than 12 months for any colorectal cancer, and advanced-stage disease.
Dr Corley's team comments, "Among patients with a positive fecal immunochemical test result, compared with follow-up colonoscopy at 8 to 30 days, follow-up after 10 months was associated with a higher risk of colorectal cancer and more advanced-stage disease at the time of diagnosis."
"Further research is needed to assess whether this relationship is causal."