Spotlight on follow-up colonoscopy

One recent study identified four barriers to follow-up colonoscopy after a positive fecal-based test result, while another found that a delay of six months or more between a positive result and follow-up colonoscopy was associated with an increased risk of colorectal cancer.


Two recent studies assessed reasons for lack of follow-up colonoscopy after a positive fecal-based test result and the association between time to follow-up colonoscopy and risk of colorectal cancer.

In the first study, researchers interviewed 30 patients with positive fecal occult blood test (FOBT) results and 30 primary care clinicians (including 10 matched patient-clinician pairs) in Ontario, Canada, from August through December 2015. Eligible patients were identified through administrative databases and were ages 50 to 74 years with a six- to 12-month-old positive FOBT, no follow-up colonoscopy, and no prior colorectal cancer diagnosis or colectomy. Eligible primary care clinicians had one or more rostered patients with a positive FOBT but no follow-up colonoscopy. Results were published online on October 25 by the American Journal of Gastroenterology.

Overall, the researchers found four reasons for lack of follow-up colonoscopy and three action plans that were made to address the positive FOBT. They found no differences when they compared reasons reported by clinicians versus those reported by patients, although more clinicians (n=10) reported unclear or unknown reasons than patients (n=1).

In order from most common to least common, the reasons given for lack of follow-up colonoscopy were as follows: 1) The patient and/or clinician believed the FOBT result was a false positive (n=28; 11 clinicians and 17 patients), 2) The patient experienced fear, anxiety, or uneasiness about colonoscopy, sometimes among other reasons (n=12; five clinicians and seven patients), 3) There was a breakdown in communication of positive FOBT results or of colonoscopy appointments (n=5; two clinicians and three patients), and 4) The patient had other health issues causing postponement or refusal of colonoscopy (n=4; two clinicians and two patients).

The action plans to follow up on the positive FOBT, in order of frequency, were: 1) Repeat the FOBT and, in some cases, monitor for colorectal cancer symptoms (n=31; 13 clinicians and 18 patients), 2) Deliberately decide not to follow up on the positive FOBT (n=13; eight clinicians and five patients), and 3) Administer a colonoscopy or an alternative lower-bowel investigation (n=10; four clinicians and six patients). Two clinicians reported an unintentional lack of follow-up action plan.

Limitations of the study include the exclusion of non-English-speaking patients and the focus on the guaiac FOBT as opposed to the newer fecal immunochemical test (FIT), the study authors noted. “Using a combination of education and policy interventions along with trained program navigators may help overcome the barriers identified in this study,” they wrote.

The second study highlighted the importance of timely follow-up colonoscopy after a positive FIT. Researchers collected data from 39,346 patients ages 50 to 69 years who participated in the Taiwanese Nationwide Screening Program from 2004 through 2012 and completed a colonoscopy more than one month after a positive FIT. They used logistic regression models to examine the association between time to follow-up colonoscopy and risks of any colorectal cancer and advanced-stage colorectal cancer. Results were published online on Oct. 31 by Clinical Gastroenterology and Hepatology.

Overall, 2,003 patients had a colorectal cancer diagnosis, and 445 had advanced-stage disease. Compared with colonoscopy within one to three months, risks were significantly higher when colonoscopy was delayed by more than six months for any colorectal cancer (adjusted odds ratio, 1.31; 95% CI, 1.04 to 1.64) and for advanced-stage disease (adjusted odds ratio, 2.09; 95% CI, 1.43 to 3.06). Risks were even higher with more than 12 months of delay for any colorectal cancer (adjusted odds ratio, 2.17; 95% CI, 1.44 to 3.26) and for advanced-stage disease (adjusted odds ratio, 2.84; 95% CI, 1.43 to 5.64) compared with a delay between one to three months. There was no significant difference in risks between follow-up colonoscopy within one to three months and follow-up colonoscopy within three to six months.

The study authors noted limitations, such as unmeasured confounders (e.g., smoking status) and the potential for contamination from symptomatic patients. “Results of this nationwide study have important implications regarding how to maximize the benefit generated from a FIT-based screening program in order to reduce the enormous burden of [colorectal cancer],” they concluded.