Screening for Stomach Diseases and Colorectal Neoplasms With the Fecal Testing

Screening for Stomach Diseases and Colorectal Neoplasms With the Fecal Testing: a Population-based Randomized Study

1. The abundant results from this trial will be helpful for assessing the feasibility of increasing stool sampling and shortening screening interval in population setting for lower and upper gastrointestinal tract lesions, their long-term effects, and the respective cost-effectiveness.
2. The study will evaluate the value of population-based screen and treatment for H. pylori infection when the HPSA is combined with the FIT.

Growing body of evidences have shown that fecal immunochemical test (FIT) outperform guaiac fecal occult blood test (gFOBT) in terms of sensitivity, neoplasm detection rate and public participation. Though direct outcome evidence is still lacking for FIT, it is anticipated to have higher colorectal cancer (CRC) mortality and incidence reduction compared with gFOBT. In Taiwan, nation-wide CRC screening program has been launched since the year of 2004 ,which provides biennial FIT screening for adults aged 50 to 69 years. Currently available data from the Bureau of Health Promotion has shown a significant stage-shift effect, an early indicator of screening effectiveness, by this screening program.

Nevertheless, the aforementioned advantages of FIT, missed neoplasms and interval cancer still exists under the current one-day stool sampling method with biennial screening interval, which might affect the effectiveness of overall screening program. Increase the number of stool samples or shortening of screening interval may be helpful for early detection of clinically significant neoplasms but it remains unclear whether such an approach may lower the screenee compliance or public participation. Moreover, its impact on the demand of confirmatory colonoscopy and cost-effectiveness of the whole screening program is still largely unknown and need to be further investigated.

In this study, we firstly aim to randomly allocate screening attendee to one of the following four arms: one-day sampling with annual screening, one-day sampling with biennial screening, two-day sampling with annual screening, and two-day sampling with biennial screening. Participation rate, positive rates of FIT, detection rate for neoplasms, positive predictive value, and long-term outcome including cancer incidence and mortality will be calculated and compared among four groups.

Secondly, in the Taiwanese population, which is a typical presentation of Asian populations, although the incidence of colorectal cancer is rapidly increasing, Helicobacter pylori-related upper gastrointestinal pathologies remain highly prevalent, which may imply that mass screening solely based on FIT could be insufficient as significant upper GI pathologies can be missed. Since the FIT does not predict upper GI pathologies, the adjunct of an「Helicobacter pylori stool-antigen test (HpSA) 」 may be a potential candidate to realize a pan-detecting assay based on stool samples in a population in which both lower and upper GI lesions are equally prevalent. Therefore, in the present study, we will also evaluate the value of simultaneous FIT and HpSA test in the community-based mass screening. We invited subjects in a randomized study to receive the FIT or the FIT plus HPSA. Those who are tested positive for HPSA will receive upper endoscopic examination and anti-H. pylori treatment. For the short-term indicators, we will evaluate the participation rate and diagnostic yield when the HPSA is added. For the long-term indicators, we will compare the incidence and mortality of gastric cancer as well as complicated peptic ulcers.

To summary, this study includes two randomized trials:

1. To make a comparison between one-day sampling with annual screening, one-day sampling with biennial screening, two-day sampling with annual screening, and two-day sampling with biennial screening using FIT;
2. To make a comparison between FIT plus HpSA and FIT alone for screening.

Finally, the cost-effectiveness analysis will be also conducted using previously established Markov model of CRC natural history and stomach diseases (such as dyspepsia, peptic ulcer disease, and gastric cancer) using the results ascertained from this trial. The primary outcomes were gastric cancer incidence and mortality rates as well as colorectal cancer incidence and mortality rates.

Inclusion Criteria:

• 50 to 69 years average-risk subjects for FIT
• 50 to 69 years subjects for HpSA

Exclusion Criteria (for the FIT-based RCT):

• Subjects who are unwilling to participate
• Subjects ineligible for colonoscopy (for the one-day vs two day FIT screening)

Exclusion Criteria (for the FIT+HPSA vs. FIT-only RCT)

• Subjects with a history of total gastrectomy
• Pregnancy
• Subjects with severe illnesses
• Subjects with prior participation in the pilot program