This article is more than 5 years old. Information may no longer be current.

Fecal immunochemical test may be viable screening option for colorectal cancer

Fecal immunochemical testing for colorectal cancer demonstrated high overall diagnostic accuracy indicating it as a viable, safe, simple, low-cost, comfortable alternative screening method for patients at increased risk for colorectal cancer, according to research published in JAMA Internal Medicine.

“Colorectal cancer (CRC) is the third-most common type of cancer in men and the second most common in women worldwide ... Recommendations for increased-risk individuals ... support only use of colonoscopy. Such a strategy is associated with higher cost, lower adherence and higher risk for rare, but serious, complications,” Anastasia Katsoula, MD, MSc, from the Aristotle University of Thessaloniki in Greece, and colleagues wrote.

“It has recently been suggested that fecal immunochemical testing (FIT) could be used for population-based screening owing to its high accuracy and adherence ... However, the potential role of FIT for screening of individuals at increased risk for CRC has not yet been fully elucidated,” they added.

Katsoula and colleagues performed a systematic review and meta-analysis of 12 studies to determine the diagnostic accuracy of FIT for screening of CRC or advanced neoplasia (AN) in high-risk asymptomatic patients with a familial or personal history of CRC (n = 6,204). They used hierarchical models to synthesize data. Seven studies had a high or unclear risk of bias.

FIT for CRC demonstrated an average sensitivity of 93% (95% CI, 53%-99%) and average specificity of 91% (95%CI, 89%-92%), resulting in a positive likelihood ratio (LR+) of 10.30 (CI 7.7-13.9) and a negative likelihood ratio (LR) of 0.08 (95% CI, 0.01-0.75). FIT for AN showed an average sensitivity of 48% (95% CI, 39%-57%) and average specificity of 93% (95% CI, 91%-94%), resulting in an LR+ of 6.55 (95% CI, 5-8.5) and an LR of 0.57 (95% CI, 0.48-0.67). FIT cutoff values between 15- and 25-g/g feces resulted in the best combination of sensitivity (93%) and specificity (94%) for the diagnosis of CRC and provided the highest LR+ (15.1) and lowest LR (0.07). Quantitative and one-sample FIT performed adequately; however, there was insufficient data on other FIT brands and multiple samples.

“FIT has high overall diagnostic accuracy for CRC in increased risk individuals,” Katsoula and colleagues concluded. “The accuracy for advanced neoplasia however is moderate, and so further study of annual FIT to assess increased performance is warranted. Heterogeneity and small sample sizes undermine the quality and validity of these findings. Further research with rigorous diagnostic accuracy studies and randomized clinical trials is warranted to assess the full effectiveness of FIT implementation as a means to promote more individualized and more flexible alternative screening options in patients at higher risk of CRC based on their own values and preferences.”

In an invited commentary, Grigorios I. Leontiadis, MD, PhD, from McMaster University in Canada, wrote that the study by Katsoula and colleagues is “timely and important” because an inexpensive, safe, acceptable, easy to use triage test is needed for screening CRC, yet their results are ultimately inconclusive because of the overall low quality of evidence.

However, he added, “it would be premature to conclusively dismiss FIT as a triage test for this population. There is a need for further well-designed and well-reported diagnostic accuracy studies on FIT for this population. If future higher-quality studies provide a body of moderate or high-quality evidence for acceptable diagnostic accuracy of FIT both for CRC and advanced neoplasia in this population, then — and only then — we will be justified to design and conduct efficacy RCTs with long-term clinical outcomes. Meanwhile, colonoscopy should be offered to the majority of individuals with higher-than-average risk of CRC, with triage tests reserved for those who, after a detailed discussion of the benefits and risk of each strategy, will not consent to having a colonoscopy unless they have a positive triage test result.” – by Alaina Tedesco

Disclosures: Katsoula and colleagues and Leontiadis report no relevant financial disclosures