Recommendations on population screening for colorectal cancer in New Zealand. Members of the National Health Committee Working Party on Population Screening for Colorectal Cancer

The National Advisory Committee on Health and Disability invited a working party to make recommendations on population screening for colorectal cancer in New Zealand. Recent results from randomised controlled trials of screening with guaiac faecal occult blood tests have provided evidence that population screening could reduce mortality from colorectal cancer. However, given the modest potential level of benefit, the considerable commitment of health sector resources, and the small but real potential for harm, the working party does not recommend population screening for colorectal cancer with faecal occult blood tests in New Zealand. The working party does nto recommend pilot colorectal cancer screening programmes in New Zealand because pilot programmes cannot address the issues of concern: the modest potential benefit and the small, but real, potential for harm. The working party does not recommend faecal occult blood testing as a screening test for colorectal cancer in average-risk individuals outside a population screening programme. Those requesting screening by faecal occult blood test should be given information about the potential risks and benefits. Follow-up bowel investigations in the public health system cannot be guaranteed without an increased allocation of resources. As there is yet no evidence from randomised controlled trials that screening with flexible sigmoidoscopy, colonoscopy or double-contrast barium enema produces a reduction in colorectal cancer mortality, the working party does not recommend population screening with these modalities. Wider consultation and further consideration should be undertaken to develop appropriate advice on surveillance recommendations for groups identified to be at increased risk of colorectal cancer. These decisions should be reviewed as evidence of benefit from new types of faecal occult blood test and other screening modalities becomes available. The working party recognises that colorectal cancer is an important cause of morbidity and mortality and recommends that New Zealand participate in international research in this area.     

Population screening for colorectal cancer

Each year in the UK, around 16,000 people die from colorectal cancer. At disease presentation, around 55% of people have advanced cancer that has spread to lymph nodes, metastasised to other organs or is so locally advanced that surgery is unlikely to be curative (Dukes' stage C or D). Overall 5-year survival for colorectal cancer in the UK is around 47-51% (compared to 64% in the USA), but only 7% at most in those presenting with metastatic disease. These facts underlie the current introduction of national bowel screening programmes in the UK. Here we assess the role of screening of the general population in reducing mortality from colorectal cancer. We do not consider the screening arrangements needed for high-risk populations, including those with inflammatory bowel disease or a strong family history of colorectal cancer.     

结直肠癌高危人群筛查依从性影响因素

结直肠癌是主要恶性肿瘤之一,近几年的发病率和死亡率都在逐年上升。结直肠癌高危人群筛查是早期诊断结直肠癌的有效方法,但由于人群对筛查的依从性较差,使筛查普及受到限制。本文综述国内外结直肠癌筛查依从性影响因素的研究进展,为制定相应的筛查政策提供建议或干预措施,以提高高危人群结直肠癌筛查的依从性,从而降低结直肠癌患者的死亡率。     

Review article: the prevention of colorectal cancer

Colorectal cancer is a leading cause of cancer mortality in the industrialized world. Survival remains poor because most cases are diagnosed at an advanced stage. It is a preventable disease as colorectal cancers usually develop slowly from an identifiable precursor lesion, the adenoma. The existing strategies for colorectal cancer prevention include dietary prevention, chemoprevention and endoscopic intervention. The exact relationship between diet, particularly fibre, and colorectal cancer remains unclear, with the most recent studies suggesting that dietary fibre may not decrease colorectal cancer risk as previously thought. Non-steroidal anti-inflammatory drugs have been shown to have a protective effect against colorectal cancer, but the adverse effect profile of the non COX-2 selective drugs, particularly the risk of gastrointestinal haemorrhage, precludes their widespread use. There is increasing evidence that colorectal cancer incidence and mortality can be decreased from endoscopic polypectomy and early detection of cancer. Faecal occult blood testing in the general population ('average-risk') has been shown in randomized trials to decrease mortality from colorectal cancer by 15--33%. Long-term results of randomized trials of the effectiveness of flexible sigmoidoscopy and colonoscopy screening in the general population are awaited. Targeting high risk individuals may also be an effective and efficient way to decrease the colorectal cancer burden. As many as 15--30% of colorectal cases may be due to hereditary factors. Individuals with one or two direct relatives affected are at moderate risk for colorectal cancer (empirical lifetime mortality from colorectal cancer approximately 10%) and approximately 2--3% of cases arise in individuals harbouring highly penetrant autosomal dominant mutations, which puts them at high-risk for colorectal cancer. Surveillance colonoscopy is offered to individuals at moderate and high risk for colorectal cancer.     

国内外大肠癌筛查现状及无创筛查方法进展

摘要： 大肠癌是严重威胁人类健康的恶性肿瘤之一, 其全球发病率和死亡率分居第3位和第2位。开展大肠癌筛查工作对大肠癌早发现、 早治疗具有重要意义。德国等经济发达国家上世纪七十年代就开始大肠癌筛查以降低其发生率和死亡率。我国也于1977年在部分大肠癌高发地区开展筛查工作, 近年在天津、 上海等大城市也开展了大肠癌筛查工作。笔者对国际和国内大肠癌筛查的现状进行综述, 探讨大肠癌筛查工作对降低大肠癌发病率和死亡率的意义, 并总结大肠癌筛查方法对筛查工作的影响。通过分析, 笔者认为国家健康计划、 科普宣传、 医保覆盖、 有效的监督机制以及合适的筛查方法是影响大肠癌筛查工作开展的重要因素。     

Screening, prevention and socioeconomic costs associated with the treatment of colorectal cancer

Colorectal cancer (CRC), the third most prevalent cancer worldwide, imposes a significant economic and humanistic burden on patients and society. One study conservatively estimated the annual expenditures for colorectal cancer to be approximately dollars US 5.3 billion in 2000, including both direct and indirect costs. However, other investigators estimated inpatient costs alone incurred in the US in 1994 to be around dollars US 5.14 billion. Therefore, the economic burden of colorectal cancer in the US could be projected to be somewhere in the range of dollars US 5.5-6.5 billion by considering that inpatient costs approximate 80% of total direct costs. No worldwide data have been published, but assuming that the US represents 25-40% of total expenditures in oncology, as seen for breast and lung cancers, a rough estimate for colorectal cancer would be in the range of dollars US 14-22 billion. Screening helps increase patient survival by diagnosing colorectal cancer early. The ideal method among the four tests most used (faecal occult blood test, flexible sigmoidoscopy, colonoscopy and double contrast barium enema) has not been identified. Economic studies of colorectal cancer screening are complex because of the many variables involved, as well as the fact that the outcomes must be followed for many years, and the lack of consensus on screening guidelines. Intuitively, modelling colorectal cancer is one way to overcome these hurdles; published modelling studies predict colorectal cancer screening programs to be within the threshold of dollars US 40000 per life-year saved. The faecal occult blood test appears to be the only clearly effective test, both from a clinical and an economic viewpoint. Important limitations are the invasiveness and inconvenience of the screening procedures, except faecal occult blood test. Patients' comfort and satisfaction are essential in improving compliance with screening recommendations, which appears to be low even in the US (35% of the general population aged over 40 years and 60% of the high-risk population), the country with the highest awareness and compliance in the world. Since colorectal cancer is generally a disease of the elderly, its economic burden is expected to grow in the near future, mainly due to population aging. Potential avenues to pursue in order to contain or reduce the economic burden of colorectal cancer would be the design and implementation of efficient screening programmes, the improvement of patient awareness and compliance with screening guidelines, the development of appropriate prevention programs (i.e. primary and secondary), and earlier diagnosis.     

大肠癌筛查研究进展

大肠癌筛查可以有效提高大肠癌患者的生存率和降低死亡率,文章通过近年来大肠癌筛查研究的文献复习、对大肠癌筛查方法的选择、筛查对象的确定及大肠癌社区筛查模式进行了综述。     

Prevention and management of colorectal cancer in women

OBJECTIVE: To review prevention and management strategies for colorectal cancer, with an emphasis on studies pertaining to women. DATA SOURCES: Articles published from January 1990 through February 2001 identified through a MEDLINE search using the term colorectal cancer and the additional terms screening, prevention, and treatment. Additional references were identified from the bibliographies of the retrieved articles. DATA SYNTHESIS: Colorectal cancer is the third most common non-skin cancer in women, after breast and lung cancers. Many women underestimate their risk of colorectal cancer, which may lead them to underuse screening measures that have been proven to reduce disease morbidity and mortality. For average-risk women and men > or = 50 years of age, pharmacists should recommend regular screening for early detection and prevention of colorectal cancer. In its earliest, most curable stages, colorectal cancer is often asymptomatic. However, patients who report signs and symptoms, such as blood in the stool, abdominal pain, changes in bowel habits, unexplained weight loss, or iron deficiency anemia, should be referred for medical evaluation. The use of chemopreventive agents for colorectal cancer, such as nonsteroidal anti-inflammatory drugs, hormone replacement therapy, and dietary calcium, holds significant promise, but further studies are needed before these agents can be recommended for cancer prevention in the general population. Surgical resection is the primary treatment modality for colorectal cancer, and adjuvant chemotherapy is recommended in patients with stage III disease and some high-risk patients with stage II disease. Pharmacists should be aware that women are more susceptible to dose-related toxicity effects of fluorouracil and leucovorin combination chemotherapy, the first-line regimen for adjuvant chemotherapy. CONCLUSION: Although often perceived as a disease that primarily affects men, colorectal cancer is an equally important health concern for women. By providing education and counseling, pharmacists can help raise women's awareness of this disease and encourage them to take steps to significantly reduce their risk.     

From screening criteria to colorectal cancer screening: what can New Zealand learn from other countries?

New Zealand is currently exploring how population-based colorectal cancer (CRC) screening will be implemented. The United Kingdom (UK), Australia, France, Italy, Spain, Finland, Denmark, the Netherlands, and Switzerland have conducted or are currently conducting pilot/feasibility studies. The UK, Australia, Finland, Canada, France and Italy are all in the early stages of implementing population-based CRC screening programmes. Most of these countries have lower CRC mortality rates than New Zealand. New Zealand is in a good position to learn from this overseas experience. Some of the key areas that will require careful consideration include; the best use of a population register to identify and invite eligible participants; the type of screening test to be used; ensuring adequate colonoscopy capacity; efficient and effective information systems; the management of high-risk groups; and how to ensure that all population groups benefit from screening.     

Cost-effective policies for cervical cancer screening. An international review

Screening programmes for cervical cancer have been credited with reducing the incidence of and mortality from cervical cancer. The main components of these screening programmes are: (i) their level of organisation; (ii) the age at which women begin screening; (iii) the age at which women discontinue screening; (iv) the interval between repeat screens; (v) the frequency at which the programmes provide screening; and (vi) the response to an abnormal screening test. However, not all screening programmes are equally efficient and differences in programme components can result in big differences in their cost effectiveness. Studies that employ cost-effectiveness analysis (CEA) to examine the efficiency of different programme components can inform the development of cost-effective programmes. This article presents findings of an international review of cost-effectiveness studies of cervical cancer screening. These studies consistently find that certain types of programmes are more cost effective than others. Programmes that are centrally organised and implemented by the public sector are reported to be more cost effective than those that use public funds for screening at other medical visits (convenience screening), or those that provide guidelines for healthcare professionals and the public to promote spontaneous discretionary screening. There is also substantial agreement about the cost effectiveness of other programme components. When multiple screenings are possible, studies report that they should generally begin at age 25 to 35 years and end at age 65 to 70 years, although it is important that older women have 3 normal Papanicolaou (Pap) smears before the discontinuation of screening. The interval for repeat screens that is reported to provide the best balance between cost and life-years saved is between 3 and 5 years. However, when a choice must be made between screening more women fewer times, or screening fewer women more times, most studies indicate that it is more cost effective to prioritize resources to obtain at least one screening for each woman. The screening of previously unscreened and high-risk populations has been shown to be especially cost effective. Despite this agreement, many studies report that models of the cost effectiveness of screening for cervical cancer are sensitive to a number of parameters. Changes in the attendance rate of the programme, the quality of the Pap smear, and the cost of the Pap smear can markedly change the cost effectiveness of a screening programme. Finally, this review discusses different perspectives of social choice analysis (e.g. CEA and cost-benefit analysis), when the objective is to prevent cervical cancer and the options are to screen, detect and treat, to reduce behavioural risk factors, and/or to pursue promising biological research.     

Review article: balancing the ideal versus the practical-considerations of colorectal cancer prevention and screening

Colorectal cancer is responsible for over 500 000 deaths annually world-wide. Death from colorectal cancer is preventable, primarily through early diagnosis of disease that has not metastasized. The disease itself may be prevented by the detection and removal of colorectal adenomas, from which more than 95% of colorectal cancers arise. Currently there are several screening methods for the disease. These include faecal occult blood tests, sigmoidoscopy, barium enema and colonscopy as well as emerging methods of virtual colonoscopy and faecal DNA testing. While direct and indirect evidence support the efficacy of these tests they differ from each other in their sensitivity, specificity, cost, and safety. Various professional organizations in different geographical regions of the world have published recommendations on which screening methods to use and when in patients at average- or high-risk. The challenge in reducing the incidence and mortality of this disease lies in increasing accessibility to and compliance with screening and delivery within a quality assured programme.     

A molecular rationale for the how, when and why of colorectal cancer screening

Colorectal cancer remains a leading cause of cancer-related mortality in the United States. Recently, colorectal cancer screening and colorectal cancer prevention have gained national attention. In response, the American Gastroenterological Association, the American College of Gastroenterology and the Agency for Healthcare Policy and Research have published recommendations for colorectal cancer screening and surveillance in patients with sporadic as well as hereditary forms of colorectal cancer. This review will focus on the basic molecular differences underlying the formation of carcinoma in patients with sporadic colorectal cancer, and the heritable syndromes of familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer (HNPCC), and juvenile polyposis (JPS). By appreciating the molecular mechanisms underlying these four types of polyp cancer syndromes, the differences in clinical time course for progression from polyp to carcinoma and in current screening recommendations for patients with sporadic adenomas, FAP, HNPCC and JPS can be better understood.     

郑州市某社区居民对大肠癌筛查的看法及认知情况的调查研究

目的 调查郑州市某社区居民对大肠癌筛查的看法及认知情况.方法 以郑州市某社区居民为对象进行调查,了解其对大肠癌筛查看法、不愿意进行筛查原因、疾病认知情况等.结果 对242户居民发放问卷并全部回收,均认为大肠癌筛查项目非常重要.但44户(18.2％)居民拒绝进行筛查,参与筛查居民有17名(7.0％)大便隐血试验阳性,有7名(41.2％)拒绝进一步行肠镜检查.认知方面,88.4％(214/242)不了解大肠癌高发病率与病死率现状;85.9％(208/242)不明确大肠癌危险因素;仅9.9％(24/242)会对大肠癌危险因素进行规避.结论 郑州市某社区居民对大肠癌认知度较低,虽认为大肠癌筛查的开展必要,但受时间等因素影响筛查率低,可通过一定干预措施提高大肠癌筛查率,以防控大肠癌.     

Should we be screening for colorectal cancer?

Mass population screening for asymptomatic neoplastic disease is now national policy in the UK for breast cancer and has been established for many years in the early diagnosis of carcinoma of the cervix. Cancer screening is based on the concept that treatment is more effective when the disease is localised and aims to detect it when it is at a less advanced clinico-pathological stage prior to the development of symptoms. Because colorectal cancer develops in benign adenomatous polyps which are often amenable to endoscopic resection, screening may both reduce the incidence of the disease as well as improving outcome from it. Flexible sigmoidoscopy screening focuses mainly on the detection of potentially malignant adenomas, their endoscopic removal producing a decrease in colorectal cancer incidence. It is a promising approach but conclusive data on effectiveness from a Medical Research Council-sponsored multicentre randomised controlled trial will not be available before 2006. Faecal occult blood testing aims to preferentially detect early stage invasive disease. Three randomised controlled trials of faecal occult blood screening show that the disease can be detected earlier in its development leading to reduced mortality from the disease--and that this is achieved at reasonable cost. The Department of Health is currently giving consideration to its national implementation.     

Mammographic screening for breast cancer: prospects for New Zealand

The Cancer Society and the Department of Health invited a working group to make recommendations on screening by mammography. Mammography offers the best opportunity for preventing deaths from breast cancer. Randomised trials suggest that mortality can be reduced by about 30% in women over 50; the value of routine mammography in younger women is still uncertain. Apart from financial costs, the main drawback of mammography is that many women receive unnecessary investigation because of false-positive results. Careful design and monitoring of programmes is essential to ensure that the benefits of screening outweigh the disadvantages. In New Zealand there is a shortage of radiologists, pathologists, and clinicians who are skilled in the specialised techniques required for the screening of asymptomatic women. Decisions about routine screening should be delayed until pilot programmes have been established, with assessment of their effectiveness, economic efficiency, and social acceptability. Recommendations for the design of such programmes are made.     

Review article: colorectal carcinoma and inflammatory bowel disease

The risk of colorectal cancer for any patient with ulcerative colitis is estimated to be 2% after 10 years, 8% after 20 years and 18% after 30 years of disease. The relative risk of colorectal cancer in Crohn's colitis is approximately 5.6 and should raise the same concerns as in ulcerative colitis. Risk factors for colorectal cancer include disease duration, early onset, extensive disease, primary sclerosing cholangitis and a family history of sporadic colorectal cancer. All patients should have a review colonoscopy 8-10 years after diagnosis to establish the extent of the disease. Surveillance should begin 8-10 years after disease onset for pancolitis and 15-20 years after disease onset for left-sided disease. Regular surveillance is recommended, with a screening interval every 3 years in the second decade of disease and annually by the fourth decade. Random biopsies should be taken at regular intervals with attention paid to dysplasia-associated lesions or masses, irregular plaques, villiform elevations, ulcers and strictures. Dysplasia is recognized as a premalignant condition, but the likelihood of progression to cancer is difficult to predict. High-grade dysplasia, confirmed by two expert gastrointestinal pathologists, is a strong indication for colectomy, as is low-grade dysplasia, although the diagnosis of low-grade dysplasia is unreliable. Surveillance programmes indicate that the overall 5-year survival rate is higher in surveyed patients, although patients still present with Dukes C cancers or disseminated malignancy. Surveillance has huge socioeconomic implications. As surveillance is not 100% effective, alternative ways of reducing the cancer risk with chemopreventive agents, such as aminosalicylates, are being considered.     

Colorectal polyps in the elderly: what should be done?

Colorectal cancer is an important cause of morbidity and mortality among Western nations, and is more common in the elderly than in younger individuals. With the general acceptance of the adenoma-carcinoma sequence, the current consideration is that colorectal cancer is preventable if all adenomas are removed before they have the chance to progress to cancer. To that end, physicians should now advocate screening for colorectal cancer and through this effort a large number of patients with adenomatous polyps will be discovered. It is important to understand the strategy in dealing with this growing population of patients with adenomas. After an initial polypectomy, patients with adenomas should be entered into a surveillance program to detect and remove recurrent adenomas. Recommended surveillance intervals are shorter for patients with a family history of colorectal cancer, those with multiple adenomas (>2), large adenomas (> or = 1cm), or those whose adenomas have high-grade dysplasia, villous architecture, or that are cancerous. Effective chemoprevention would be a potential method of lengthening colonoscopic surveillance intervals. Unfortunately, no treatment has been found to be effective enough to alter our current surveillance practice. The only recommendation that can be made at this time for those patients with a history of colonic adenomas is to add 3 g/day of calcium carbonate to their diet, though its effect on adenoma recurrence is modest.     

上海市金山工业区结直肠癌筛查结果分析

目的：分析社区居民结直肠癌筛查结果,以降低结直肠癌的发病率和死亡率。方法：2013年5月—2015年8月对金山工业区辖区内50~74岁社区常住人群采用问卷危险度评估和大便潜血试验（FOBT）进行初步筛查,对初筛阳性者进一步作结肠镜检查。结果：7647人参与了结直肠癌筛查,参与率为52.51%,初筛阳性1512人,阳性率19.77%,其中600人接受结肠镜检查,240例检出病变,病变检出率为40.00%,其中结直肠癌7例（1.17%）,息肉153例（25.50%）,肠炎74例（12.33%）,其他肠道病变6例（1.00%）。结论：结直肠癌筛查对结直肠癌的早发现、早诊断、早治疗具有重要意义。     

Review article: chemoprevention of colorectal cancer

Colorectal cancer is a disease with a high mortality at present, due to the late stage at which many cases present. Attention is therefore focusing on preventative strategies for colorectal cancer given that polyps appear to be identifiable and treatable precursor lesions of this disease. Endoscopic polypectomy has been shown to reduce the incidence of colorectal cancer and there is a good case for endoscopic screening of the general population. However, this will require a large amount of manpower and resources and its success will also depend on the overall compliance of the population. Epidemiological studies have shown that individuals reporting a regular intake of aspirin and other non-steroidal anti-inflammatory drugs have a reduced risk of developing colorectal polyps and cancer. Similarly, a number of natural substances, such as calcium and folate, when supplemented regularly in the diet, have also been linked to a possible decreased incidence of colorectal cancer. This has led to the concept of using such agents to reduce the number of cases of colorectal cancer. In this article, we review the current evidence for the use of these and other agents for the chemoprevention of colorectal cancer, together with theories as to their possible mechanisms of action.     

某社区2013年大肠癌筛查实践

目的:对某社区2013年1月~2013年12月居民大肠癌筛查情况进行分析。方法:采用免疫法粪便潜血FOBT检测以及问卷调查对某社区居民进行筛查,通过初筛和精筛两个步骤来完成大肠癌的筛查,对结果进行分析。结果:823例患者属于高危人群,其阳性率为22.85%;粪便潜血FOBT检测223例患者呈现为阳性,阳性率为6.19%,经过上述两项初次筛查其结果表现为综合分析,最终明确2551人列入到高危人群,其高危阳性率为70.82%;1500例患者接受了电子结肠镜检查,受检率为58.80%,发现息肉、息肉样增生近1000例,发现直、结肠癌40例,中重度异型增生等癌前病变110例,肠镜检查率为76.67%。在40~49岁年龄组中其大肠病变的检出率为30.21%,年龄≥70岁中大肠病变的检出率最高,达到了58.37%。男性患者肠镜检出率达到了56.37%,而女性患者明显较低,只有37.65%。结论:某社区居民大肠癌的发病率相对来说较高,并且年龄越大发病率越高,男性发病率高于女性,应加大宣传力度,提高防治意识。