Many countries, regions and institutions around the world have successively formulated guidelines and specifications for colorectal cancer (CRC) screening, and determined the starting and ending ages and methods of CRC screening. However, the level of economic development and the allocation of medical resources in different countries are different, and the screening strategies of each guideline have more obvious differences.
US Preventive Services Task Force (USPSTF) screening guidelines:
In 2021, the USPSTF updated its CRC screening guidelines formulated in 2016 after a lapse of 5 years, pointing out that 45 to 75 years old have an average risk (no history of CRC, adenomatous polyps, inflammatory bowel disease, no family history) Asymptomatic people should participate in the CRC screening; whether the 76-85 year-old people participate in the screening should be determined according to their health status, whether they have participated in the screening before and their personal wishes; people who have not been screened before are more likely to get from participating at this time Benefit; it is not recommended to participate in the screening for people over 86 years old.
Selectable screening items include:
(1) Perform high-sensitivity gFOBT once a year;
(2) FIT is carried out once a year;
(3) Perform multi-target fecal FIT-DNA once every 1 to 3 years;
(4) Perform colonoscopy once every 10 years;
(5) CT colonography is performed once every 5 years;
(6) Perform soft sigmoidoscopy once every 5 years;
(7) Perform soft sigmoidoscopy once every 10 years + FIT once a year.
The guideline does not indicate a single preferred screening measure, but proposes a variety of alternative screening methods, which can be selected according to the patient's individual situation, which helps to improve patient compliance. Similarly, in view of the current situation of my country's urban-rural and regional differences, screening strategies can be selected according to local economic development levels.
American College of Gastroenterology (ACG) Screening Guidelines
ACG updated its screening guidelines issued in 2017 in 2021. The guideline strongly recommends CRC screening for the average risk population of 50 to 75 years old, and it is recommended to screen the average risk population of 45 to 49 years old to reduce the incidence of advanced adenoma, CRC, and the mortality rate of CRC; and 75 People over the age of the year are determined according to individual circumstances.
Screening method
Colonoscopy every 10 years or FIT once a year is the preferred method; those who cannot accept the preferred method can choose to have a sigmoid colonoscopy every 5 to 10 years and a multi-target stool FIT every 3 years -DNA examination, CT colonography every 5 years, or capsule endoscopy every 5 years.
Septin9 is not recommended for CRC screening. Among the various screening methods, the guide suggests that colonoscopy and FIT are the more preferred methods; at the same time, capsule endoscopy is an alternative method. The guidelines provide additional conditional recommendations for those with a family history.
If one first-degree relative is diagnosed with CRC or advanced polyps before the age of 60, or if two or more first-degree relatives are diagnosed with CRC or advanced polyps at any age, it is recommended to be at least 40 years old or relatives Before 10 years of age (whichever is earlier), colonoscopy is selected for CRC screening, and then every 5 years thereafter.
If a first-degree relative is diagnosed with CRC or advanced polyps after 60 years of age, it is recommended to start screening before 40 years of age or 10 years before the minimum age of the relative, and then resume the general screening procedures. For those with a heavier burden of familial CRC (the number of affected relatives and/or the younger age), genetic evaluation is recommended. In terms of chemoprevention, the guidelines conditionally recommend low-dose aspirin for individuals 50-69 years old, cardiovascular disease risk ≥10% in the next 10 years, low bleeding risk, and willing to take aspirin for at least 10 years to reduce the risk of CRC; however, it also points out , Taking aspirin is not a substitute for CRC screening. In addition, the guideline also regulates endoscopy operations, requiring all endoscopists participating in CRC screening to have a cecal arrival rate (CIR)> 95%, adenoma detection rate (ADR) ≥ 25%, and a withdrawal time (WT )>6 min.
Regarding how to improve the population’s compliance with CRC screening, the guidelines also give recommendations: adopt organized screening instead of opportunistic screening; provide guidance and reminders to patients, and clinicians (primary care providers or General practitioners) conduct academic interventions, use clinical decision support tools, etc. These strategies to improve the compliance of CRC screening also provide a good reference for the construction of my country's future screening system.
National Health and Medical Research Council (NHMRC) Screening Guidelines
In the guidelines issued by NHMRC in 2017, it is recommended that asymptomatic people aged 50-74 years old have an average risk of FIT once every two years, once the result is positive, the colonoscopy should be improved as soon as possible.
The guidelines also propose some other strategies to improve the effectiveness of screening, such as FIT every year between the ages of 50 and 74; 1 colonoscopy at the age of 50 and then 1 FIT every 2 years; at the age of 55, 65, and 75 One colonoscopy was performed respectively; FIT was performed once every two years between the ages of 50 and 74, and those with negative results were performed soft sigmoidoscopy at the age of 50 or 54, 64, 74.
The screening strategy finalized by the guidelines strikes the best balance between benefit, damage and cost-effectiveness under the current conditions in Australia. The guidelines also pointed out that for those with a family history of CRC in the first and second degree relatives, the starting age for FIT every 2 years should be advanced in varying degrees according to the number and age of the sick relatives. In addition, it is necessary to increase the Colonoscopy once every 5 years.
Canadian Preventive Health Care Task Force (CTFPHC) Screening Guidelines
The CRC screening recommendations issued by CTFPHC in 2016 define those who are not at high risk of CRC as those who do not have the following conditions:
(1) CRC or polyps, inflammatory bowel disease;
(2) Signs or symptoms of CRC;
(3) CRC history of one or more first-degree relatives;
(4) CRC-related genetic syndromes.
This guideline strongly recommends CRC screening for people aged 60-74, and it is weakly recommended for people aged 50-59. It is no longer recommended for people over 75 or based on individual conditions. The specific screening method is recommended to perform gFOBT or FIT once every 2 years, or perform soft sigmoidoscopy once every 10 years. Considering the additional medical resources consumed by colonoscopy and the risk of complications, it is not recommended to directly use it as a screening method.
"Guidelines for Screening and Early Diagnosis and Treatment of Colorectal Cancer in China (2020, Beijing)"
In 2020, the National Cancer Center China Colorectal Cancer Screening and Early Diagnosis and Treatment Guidelines Development Expert Group formulated the "Chinese Colorectal Cancer Screening and Early Diagnosis and Early Treatment Guidelines (2020, Beijing)", which is the first evidence-based medical evidence in my country Rather than the consensus opinion of experts on CRC screening guidelines, the evidence retrieval incorporates local research results, which is more suitable for my country's national conditions and is more conducive to standardizing CRC screening programs and early diagnosis and treatment techniques in my country's clinical practice.
The guidelines define those who do not have the following risk factors as general risk groups:
(1) First-degree relatives have a history of CRC;
(2) I have a history of CRC/intestinal adenoma/8~10 years of long-term unhealed inflammatory bowel disease;
(3) I have a positive FOBT.
Taking into account that the incidence of CRC in the Chinese population has increased since the age of 40, the guidelines recommend that the general risk population receive CRC risk assessment from the age of 40. Those who are assessed as low- and medium-risk receive CRC screening at the age of 50 to 75, and those who are assessed as high-risk should be screened for CRC in advance to 40 years old. Unfortunately, limited by the lack of evidence for high-level evidence-based medicine, the guide only lists the risk factors for sporadic CRC and summarizes common CRC risk assessment models, but does not make clear recommendations for the assessment criteria of high-risk groups.
In short, CRC screening and prevention is not only a medical problem, but also a social problem that relies on policy support and is resolved by the participation of all sectors of society. The Chinese government attaches great importance to people’s livelihood and pays attention to cancer prevention and control. With the gradual implementation of the guidelines proposed in the "Healthy China Action (2019-2030)", the screening and prevention of CRC in my country will surely move from point to point, step by step, and scientifically. Effectively gradually promote and implement, form a stable and continuous organized screening program, and ultimately achieve the goal of real benefiting the people, saving national medical and health expenditures, and improving the level of public health and clinical medical research.