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, according to a study published by JAMA.

The fecal immunochemical test (FIT) is commonly used for colorectal cancer screening and positive test results need to be followed by a complete colon examination, typically with colonoscopy; however, recommendations for how quickly to complete follow-up differ and lack a strong evidence base. Douglas A. Corley, M.D., Ph.D., of Kaiser Permanente Northern California, Oakland, and colleagues conducted a study that included patients with a positive FIT result who had a follow-up colonoscopy.

Of the 70,124 patients with positive FIT results (median age, 61 years; men, 53 percent), there were 2,191 cases of any colorectal cancer and 601 cases of advanced-stage disease diagnosed. The researchers found that there was no significant increase in risk of overall colorectal cancer or advanced colorectal cancer associated with colonoscopy follow-up within 10 months compared with 8 to 30 days. There was a higher risk of stage II colorectal cancer at 7 to 9 months; of any colorectal cancer, advanced-stage disease, and stage II and IV colorectal cancer at 10 to 12 months; and of advanced adenomas, any colorectal cancer, advanced-stage disease, and stages II-IV colorectal cancer at more than 12 months.

"Further research is needed to assess whether this relationship is causal," the authors write.