The Effect of Nationwide Organized Cancer Screening Programs on Gastric Cancer Mortality: A Synthetic Control Study.

BACKGROUND & AIMS: Nationwide organized gastric cancer (GC) screening programs have been running for decades in South Korea and Japan. This study conducted a quasi-experimental analysis to assess the population impact of these programs on GC mortality. METHODS: We used the flexible synthetic control method (SCM) to estimate the effect of the screening programs on age-standardized GC mortality and other upper gastrointestinal (UGI) diseases (esophageal cancer and peptic ulcer) among people aged ≥40 years. World Health Organization mortality data and country-level covariates from the World Bank and the Global Burden of Diseases study were used for the analyses. We compared postintervention trends in outcome with the counterfactual trend of the synthetic control and estimated average postintervention rate ratios (RRs) with associated 95% confidence intervals (CIs). A series of sensitivity analyses were conducted. RESULTS: The preintervention fits were acceptable for the analyses of South Korea and Japan's GC mortality but poor for Japan's other UGI disease mortality. The average postintervention RRs were 0.83 (95% CI, 0.71-0.96) for GC mortality and 0.72 (95% CI, 0.57-0.90) for other UGI disease mortality in South Korea. The RR reached 0.59 by the 15th year after the initiation of nationwide screening. For Japan, the average RRs were 0.97 (95% CI, 0.88-1.07) for GC mortality and 0.93 (95% CI, 0.68-1.28) for other UGI disease mortality. Sensitivity analysis reveals the result for Japan may potentially be biased. CONCLUSIONS: South Korea's nationwide GC screening has apparent benefits, whereas the Japanese program's effectiveness is uncertain. The experiences of South Korea and Japan could serve as a reference for other countries.

Cancer screening programs in South-east Asia and Western Pacific.

BACKGROUND: The burden of cancer can be altered by screening. The field of cancer screening is constantly evolving; from the initiation of program for new cancer types as well as exploring innovative screening strategies (e.g. new screening tests). The aim of this study was to perform a landscape analysis of existing cancer screening programs in South-East Asia and the Western Pacific. METHODS: We conducted an overview of cancer screening in the region with the goal of summarizing current designs of cancer screening programs. First, a selective narrative literature review was used as an exploration to identify countries with organized screening programs. Second, representatives of each country with an organized program were approached and asked to provide relevant information on the organizations of their national or regional cancer screening program. RESULTS: There was wide variation in the screening strategies offered in the considered region with only eight programs identified as having an organized design. The majority of these programs did not meet all the essential criteria for being organized screening. The greatest variation was observed in the starting and stopping ages. CONCLUSIONS: Essential criteria of organized screening are missed. Improving organization is crucial to ensure that the beneficial effects of screening are achieved in the long-term. It is strongly recommended to consider a regional cancer screening network.

An Approach to the Primary and Secondary Prevention of Gastric Cancer in the United States.

BACKGROUND & AIMS: Gastric cancer (GC) remains a leading cause of mortality among certain racial, ethnic, and immigrant groups in the United States (US). The majority of GCs are diagnosed at advanced stages, and overall survival remains poor. There exist no structured national strategies for GC prevention in the US. METHODS: On March 5-6, 2020 a summit of researchers, policy makers, public funders, and advocacy leaders was convened at Stanford University to address this critical healthcare disparity. After this summit, a writing group was formed to critically evaluate the effectiveness, potential benefits, and potential harms of methods of primary and secondary prevention through structured literature review. This article represents a consensus statement prepared by the writing group. RESULTS: The burden of GC is highly inequitably distributed in the US and disproportionately falls on Asian, African American, Hispanic, and American Indian/Alaskan Native populations. In randomized controlled trials, strategies of Helicobacter pylori testing and treatment have been demonstrated to reduce GC-specific mortality. In well-conducted observational and ecologic studies, strategies of endoscopic screening have been associated with reduced GC-specific mortality. Notably however, all randomized controlled trial data (for primary prevention) and the majority of observational data (for secondary prevention) are derived from non-US sources. CONCLUSIONS: There exist substantial, high-quality data supporting GC prevention derived from international studies. There is an urgent need for cancer prevention trials focused on high-risk immigrant and minority populations in the US. The authors offer recommendations on how strategies of primary and secondary prevention can be applied to the heterogeneous US population.

Emerging technologies for cervical cancer screening.

Cervical cancer remains a concern worldwide, and cervical cancer screening plays an important role in reducing the burden of this disease. Although cytology is still the main strategy for cervical cancer screening, it has gradually changed to human papillomavirus testing. The specificity of human papillomavirus testing is lower than that of cytology, which leads to an increased rate of colposcopy after positive results. To decrease colposcopic examinations, an efficient triage method is needed for human papillomavirus screening. New biomarkers have been developed and evaluated for primary screening and triage of abnormal cytology or human papillomavirus-positive results. Their sensitivity and specificity were estimated and compared with those of cytology. In the present study, the following new techniques were examined: p16/Ki67 dual staining, DNA methylation, micro-ribonucleic acid, chromosomal abnormalities, Claudins and DNA ploidy. Evaluation studies of p16/Ki67 dual staining and DNA methylation were more advanced than those of other options. When p16/Ki67 dual staining was used for triage for human papillomavirus testing, the sensitivity of 2 or greater cervical intraepithelial neoplasia (CIN2+) detection was higher than that of cytology without decreased specificity. Although there are several types of DNA methylation, sensitivity and specificity were moderate for detecting CIN2+. S5 classifier is a commercialized product that consists of viral methylation, and high sensitivity with decreased specificity has been reported. Considering its combination with self-sampling, DNA methylation is a highly anticipated technique along with human papillomavirus testing for the next generation of cervical cancer screening. However, the backgrounds for cervical cancer screening differ among countries and further study is needed to identify the best available method.

Correction to: Tailored message interventions versus typical messages for increasing participation in colorectal cancer screening among a non-adherent population: A randomized controlled trial.

An amendment to this paper has been published and can be accessed via the original article.

Frequency of unsatisfactory cervical cytology smears in cancer screening of Japanese women: A systematic review and meta-analysis.

The Bethesda system (TBS) has been used for cervical cytological diagnosis in Japan since 2008. Evaluation of specimen adequacy is the most important aspect of quality assurance and for precise diagnosis in TBS. A systematic review and meta-analysis were carried out to assess the unsatisfactory specimen rate in the primary cervical cancer screening setting in Japan. Ovid Medline and Ichushi-Web databases were searched from inception through to May 2017. Prospective and retrospective studies that reported the proportion of unsatisfactory specimens in healthy asymptomatic Japanese women in a cervical cancer screening program were eligible for inclusion; 17 studies were included in the meta-analysis. The random-effects model meta-analysis calculated summary estimates of the unsatisfactory rate of 0.60% (95% confidence interval [CI], 0.18-1.96%; I2 = 99%) for conventional cytology and 0.04% (95% CI, 0.00-0.35%; I2 = 99%) for liquid-based cytology (LBC). However, comparative results between conventional and liquid-based cytology, based on four direct and nine comparative studies, showed no significant difference (summary odds ratio = 3.5 × 10-2 favoring LBC [95% CI, 6.9 × 10-4 -1.7]; I2 = 98%). In the subgroup analyses and meta-regressions, use of non-cotton devices for conventional cytology and use of a particular platform for LBC were associated with lower unsatisfactory rates. Meta-regression also suggested chronological improvement in unsatisfactory rates for both tests. In Japanese cervical cancer screening programs, conventional cytology remains prevalent. Future research needs to focus on evaluating the impact of screening programs using LBC by comparing the accuracy, performance, and cost-effectiveness with conventional cytology in the Japanese population.

Association between age factors and strategies for promoting participation in gastric and colorectal cancer screenings.

BACKGROUND: Despite the long history of cancer screening in Japan, the participation rates in gastric and colorectal cancer screenings have not increased. Strategies for improving the participation rates have been proposed, but differences in their effects among different age groups remain unclear. METHODS: The Japanese government conducted a national survey in all municipalities in Japan in 2010 to investigate whether the implementation of promotion strategies increased participation in cancer screening. We investigated the association between age factors and strategies for promoting participation in cancer screening based on this national survey. Multiple regression analysis with generalized linear model was performed using the participation rates in gastric and colorectal cancer screenings as dependent variables, and the following strategies for promoting participation as independent variables: 1) personal invitation letters, 2) household invitation letters, 3) home visits by community nurses, 4) screenings in medical offices, and 5) free cancer screening programs. RESULTS: One thousand six hundred thirty nine municipalities for gastric cancer screening and 1666 municipalities for colorectal cancer screening were selected for the analysis. In gastric and colorectal cancer screenings, the participation rates of individuals aged 60-69 years was higher than those of other age groups. Personal and household invitation letters were effective promotion strategies for all age groups, which encouraged even older people to participate in gastric and colorectal cancer screenings. Screening in medical offices and free screenings were not effective in all age groups. Home visits were effective, but their adoption was limited to small municipalities. CONCLUSIONS: To clarify whether promotion strategies can increase the participation rate in cancer screening among different age groups, 5 strategies were assessed on the basis of a national survey. Although personal and household invitation letters were effective strategies for promoting participation in cancer screening for all age groups, these strategies equally encouraged older people to participate in gastric and colorectal cancer screenings. If resource for sending invitation letters are limited, priority should be given to individuals who are in their 50s and 60s for gastric and colorectal cancer screening.

Cancer screening guidelines and policy making: 15 years of experience in cancer screening guideline development in Japan.

Cancer deaths have remained a heavy burden in Japan, thus cancer screening has been anticipated to be a practical strategy for reducing mortality from cancers. The Basic Plan to Promote Cancer Control Program published in 2006 stated that evidence-based cancer screening is required. At the conception of national cancer screening programs, there were no cancer screening assessments. From 1998 to 2001, Hisamichi formed committees for the assessment of cancer screening and published three reports. These reports were the cornerstone in assessing primary studies of cancer screening in Japan which served as a stimulus for the development of cancer screening guidelines. Since 2003, research groups funded by the National Cancer Center have developed cancer screening guidelines based on established methods in reference to international standards. Screening guidelines for the following cancers have been published: gastric, colorectal, lung, prostate, cervical and breast cancers. Recommendations for screening are made following assessment of the balance of benefits and harms. The recommendation has been divided for population-based screening and opportunistic screening. New screening techniques with insufficient evidence have been suggested to further undergo research. The national committee has continued to appraise their evidence for cancer screening based on established guidelines and has discussed implementation problems. The screening methods for breast and gastric cancers have been revised based on cancer screening guidelines. Cancer screening guidelines have increasingly contributed to the promotion of evidence-based cancer screening for national programs. To provide appropriate cancer screening evidence, additional studies to further improve the methodology for guideline development are warranted.

Update version of the Japanese Guidelines for Gastric Cancer Screening.

BACKGROUND: Although the incidence and mortality of gastric cancer have gradually decreased, its burden remains in East Asian countries. Gastric cancer screening has been performed in Japan since 1983, and the introduction of new screening techniques has been eagerly anticipated. OBJECTIVE: To promote evidence-based screening, the Japanese guidelines for gastric cancer screening have been revised based on the new studies. METHODS: The guidelines for gastric cancer screening have been developed according to a previously established method. To assess evidence regarding the effectiveness of the screening methods, a systematic review was conducted based on an analytic framework including clinical questions aiming at reducing mortality from gastric cancer. The following methods were assessed for gastric cancer screening: upper gastrointestinal series (radiographic screening), gastrointestinal endoscopy (endoscopic screening), Helicobacter pylori antibody test and serum pepsinogen tests. Based on the balance of the benefits and harms of each screening method, recommendations for population-based and opportunistic screenings were formulated. FINDINGS: After the Japanese guidelines for gastric cancer screening were published in 2005, several observational studies on radiographic and endoscopic screenings have been reported. Three case-control studies have evaluated mortality reduction from gastric cancer by endoscopic screening. Notably, evidence of the H. pylori antibody and serum pepsinogen tests was insufficient. Although false-positive results, false-negative results, and complications were observed in endoscopic and radiographic screenings, the complication rates were higher in endoscopic screening than in radiographic screening. Overdiagnosis was not estimated directly in both methods. RECOMMENDATIONS: Radiographic and endoscopic screenings for gastric cancer are recommended for population-based and opportunistic screenings. The H. pylori antibody and serum pepsinogen tests are not recommended for population-based screening because of insufficient evidence.

Potential capacity of endoscopic screening for gastric cancer in Japan.

In 2016, the Japanese government decided to introduce endoscopic screening for gastric cancer as a national program. To provide endoscopic screening nationwide, we estimated the proportion of increase in the number of endoscopic examinations with the introduction of endoscopic screening, based on a national survey. The total number of endoscopic examinations has increased, particularly in clinics. Based on the national survey, the total number of participants in gastric cancer screening was 3 784 967. If 30% of the participants are switched from radiographic screening to endoscopic screening, approximately 1 million additional endoscopic examinations are needed. In Japan, the participation rates in gastric cancer screening and the number of hospitals and clinics offering upper gastrointestinal endoscopy vary among the 47 prefectures. If the participation rates are high and the numbers of hospitals and clinics are small, the proportion of increase becomes larger. Based on the same assumption, 50% of big cities can provide endoscopic screening with a 5% increase in the total number of endoscopic examinations. However, 16.7% of the medical districts are available for endoscopic screening within a 5% increase in the total number of endoscopic examinations. Despite the Japanese government's decision to introduce endoscopic screening for gastric cancer nationwide, its immediate introduction remains difficult because of insufficient medical resources in rural areas. This implies that endoscopic screening will be initially introduced to big cities. To promote endoscopic screening for gastric cancer nationwide, the disparity of medical resources must first be resolved.

Optimal interval of endoscopic screening based on stage distributions of detected gastric cancers.

BACKGROUND: Although Korea and Japan have a national gastric cancer screening program, their screening intervals are different. The optimal screening interval of endoscopic screening in Japan was investigated based on the stage distributions of screen-detected gastric cancers. METHODS: Patients with gastric cancer detected by endoscopic and radiographic screenings were selected from the Niigata City Medical Association database. The stage distributions of the detected gastric cancers were compared among patients with different screening histories in both groups. Gastric cancer specific survival rates were analyzed using the Kaplan-Meier method with the log-rank test. RESULTS: There were 1585 and 462 subjects in the endoscopic and radiographic screening groups, respectively. In the endoscopic screening group, the stage IV proportion was lower in patients with screening history 1 and 2 years before diagnosis than in patients without screening history. Stage IV development was significantly related to the absence of screening history (p < 0.001); however, there were no differences between patients who had endoscopic screening history 2 and 3 years before diagnosis. The survival rates were not significantly different between patients with endoscopic screening 1 and 2 years previously (p = 0.7763). The survival rates were significantly higher in patients with endoscopic screening history 1 and 2 years before diagnosis than in patients without screening history (p < 0.001), and in patients with endoscopic screaming 3 years before diagnosis (P < 0.0069). CONCLUSION: The endoscopic screening interval for gastric cancer can be expanded to at least 2 years based on the stage distributions of detected cancers and the patient survival rates.

Receiver operating characteristic analysis of prediction for gastric cancer development using serum pepsinogen and Helicobacter pylori antibody tests.

BACKGROUND: Chronic Helicobacter pylori infection plays a central role in the development of gastric cancer as shown by biological and epidemiological studies. The H. pylori antibody and serum pepsinogen (PG) tests have been anticipated to predict gastric cancer development. METHODS: We determined the predictive sensitivity and specificity of gastric cancer development using these tests. Receiver operating characteristic analysis was performed, and areas under the curve were estimated. The predictive sensitivity and specificity of gastric cancer development were compared among single tests and combined methods using serum pepsinogen and H. pylori antibody tests. RESULTS: From a large-scale population-based cohort of over 100,000 subjects followed between 1990 and 2004, 497 gastric cancer subjects and 497 matched healthy controls were chosen. The predictive sensitivity and specificity were low in all single tests and combination methods. The highest predictive sensitivity and specificity were obtained for the serum PG I/II ratio. The optimal PG I/II cut-off values were 2.5 and 3.0. At a PG I/II cut-off value of 3.0, the sensitivity was 86.9% and the specificity was 39.8%. Even if three biomarkers were combined, the sensitivity was 97.2% and the specificity was 21.1% when the cut-off values were 3.0 for PG I/II, 70 ng/mL for PG I, and 10.0 U/mL for H. pylori antibody. CONCLUSIONS: The predictive accuracy of gastric cancer development was low with the serum pepsinogen and H. pylori antibody tests even if these tests were combined. To adopt these biomarkers for gastric cancer screening, a high specificity is required. When these tests are adopted for gastric cancer screening, they should be carefully interpreted with a clear understanding of their limitations.

Quality assurance manual of endoscopic screening for gastric cancer in Japanese communities.

The Japanese government introduced endoscopic screening for gastric cancer in 2015 as a public policy based on the Japanese guidelines on gastric cancer screening. To provide appropriate endoscopic screening for gastric cancer in Japanese communities, we developed a quality assurance manual of endoscopic screening and recommend 10 strategies with their brief descriptions as follows: (i) Formulation of a committee responsible for implementing and managing endoscopic screening, and for deciding the suitable implementation methods in consideration of the local context; (ii) Development of an interpretation system that leads to a final judgement to standardize endoscopic examination and improve its accuracy; (iii) Preparation of management and reporting systems for adverse effects by the committee for safety management; (iv) Obtaining informed consent before operation following adequate explanations regarding the benefits and harms of endoscopic screening; (v) Avoidance of frequent screenings to reduce false-positive results and overdiagnosis. As a reference, the target age group is ≥50 years, and the screening interval is 2 years; (vi) Keeping the biopsy rate within 10% as post-biopsy bleeding may occur. Before endoscopic screening, any history of antithrombotic drug usage should be checked; (vii) Nonadministration of sedation in endoscopic screening for safety management; (viii) Adherence to proper endoscopic cleaning and disinfection to reduce infection; (ix) Use of a checklist to achieve optimal program preparation when municipal governments introduce endoscopic screening; (x) Identification of the aims and roles by referring to a checklist if primary care physicians decide to participate in endoscopic screening.

The Japanese Guidelines for Breast Cancer Screening.

OBJECTIVE: The incidence of breast cancer has progressively increased, making it the leading cause of cancer deaths in Japan. Breast cancer accounts for 20.4% of all new cancers with a reported age-standardized rate of 63.6 per 100 000 women. METHODS: The Japanese guidelines for breast cancer screening were developed based on a previously established method. The efficacies of mammography with and without clinical breast examination, clinical breast examination and ultrasonography with and without mammography were evaluated. Based on the balance of the benefits and harms, recommendations for population-based and opportunistic screenings were formulated. RESULTS: Five randomized controlled trials of mammographic screening without clinical breast examination were identified for mortality reduction from breast cancer. The overall relative risk for women aged 40-74 years was 0.75 (95% CI: 0.67-0.83). Three randomized controlled trials of mammographic screening with clinical breast examination served as eligible evidence for mortality reduction from breast cancer. The overall relative risk for women aged 40-64 years was 0.87 (95% confidence interval: 0.77-0.98). The major harms of mammographic screening were radiation exposure, false-positive cases and overdiagnosis. Although two case-control studies evaluating mortality reduction from breast cancer were found for clinical breast examination, there was no study assessing the effectiveness of ultrasonography for breast cancer screening. CONCLUSIONS: Mammographic screening without clinical breast examination for women aged 40-74 years and with clinical breast examination for women aged 40-64 years is recommended for population-based and opportunistic screenings. Clinical breast examination and ultrasonography are not recommended for population-based screening because of insufficient evidence regarding their effectiveness.

Tailored message interventions versus typical messages for increasing participation in colorectal cancer screening among a non-adherent population: A randomized controlled trial.

BACKGROUND: The purpose of this study was to examine the effectiveness and cost-efficiency of a tailored message intervention compared with a non-tailored message intervention for increasing colorectal cancer (CRC) screening rates among a non-adherent population, in a community-based client reminder program. METHODS: After a baseline survey for psychological segmentation, 2140 eligible individuals were randomly assigned either to a group with a tailored matched-message condition (N = 356), a group with a non-tailored unmatched-message condition (N = 355), or to two control groups, one using a typical message with a professional design (N = 717) and one without a professional design (N = 712). The main outcome measure was attendance rates in a community-organized CRC screening program within five months of receiving a print reminder. RESULTS: There was a significant difference in fecal occult blood test (FOBT) attendance rates at follow-up assessments between the tailored matched-message condition (14.0 %) and the control (9.9 %; OR = 1.48, p = 0.026), while there was no significant difference between the unmatched-message condition (11.0 %) and the control (OR = 1.12, p = 0.558), and between the matched-message condition and the unmatched-message condition (OR = 1.32, p = 0.219). The cost of a one-person increase in FOBT screening was 3,740 JPY for the tailored matched-message condition, while it was 2,747 JPY for the control. CONCLUSIONS: A tailored-message intervention for segmented individuals designed to increase CRC screening rates in a community-based client reminder program was significantly effective compared to a usual reminder, but not more effective than an unmatched message in a randomized controlled trial, and was not sufficiently effective to highlight its value from a cost perspective. Therefore, the tailored intervention including target segmentation needs to be improved for future implementation in a CRC screening program for a non-adherent population. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000004384 . Date of Registration: March 2011.

Mortality reduction from gastric cancer by endoscopic and radiographic screening.

To evaluate mortality reduction from gastric cancer by endoscopic screening, we undertook a population-based cohort study in which both radiographic and endoscopic screenings for gastric cancer have been carried out. The subjects were selected from the participants of gastric cancer screening in two cities in Japan, Tottori and Yonago, from 2007 to 2008. The subjects were defined as participants aged 40-79 years who had no gastric cancer screening in the previous year. Follow-up of mortality was continued from the date of the first screening to the date of death or up to December 31, 2013. A Cox proportional hazards model was used to estimate the relative risk (RR) of gastric cancer incidence, gastric cancer death, all cancer deaths except gastric cancer death, and all-causes death except gastric cancer death. The number of subjects selected for endoscopic screening was 9950 and that for radiographic screening was 4324. The subjects screened by endoscopy showed a 67% reduction of gastric cancer compared with the subjects screened by radiography (adjusted RR by sex, age group, and resident city = 0.327; 95% confidence interval [CI], 0.118-0.908). The adjusted RR of endoscopic screening was 0.968 (95%CI, 0.675-1.387) for all cancer deaths except gastric cancer death, and 0.929 (95%CI, 0.740-1.168) for all-causes death except gastric cancer death. This study indicates that endoscopic screening can reduce gastric cancer mortality by 67% compared with radiographic screening. This is consistent with previous studies showing that endoscopic screening reduces gastric cancer mortality.

A meta-analysis of mammographic screening with and without clinical breast examination.

Mammographic screening with clinical breast examination has been recommended in Japan since 2000. Although mammographic screening without clinical breast examination has not been recommended, its introduction is anticipated. The efficacies of mammographic screening with and without clinical breast examination were evaluated based on the results of randomized controlled trials. PubMed and other databases for studies published between 1985 and 2014 were searched. The study design was limited to randomized controlled trials to evaluate mortality reduction from breast cancer. Five studies were eligible for meta-analysis of mammographic screening without clinical breast examination. The relative risk for women aged 40-74 years was 0.75 (95% confidence interval, 0.67-0.83). Three studies evaluated the efficacy of mammographic screening with clinical breast examination. The relative risk for women aged 40-64 years was 0.87 (95% confidence interval, 0.77-0.98). The number needed to invite was always lower in mammographic screening without clinical breast examination than in mammographic screening with clinical breast examination. In both screening methods, the number needed to invite was higher in women aged 40-49 years than in women aged 50-70 years. These results suggest that mammographic screening without clinical breast examination can afford higher benefits to women aged 50 years and over. Although evidence of the efficacy of mammographic screening without clinical breast examination was confirmed based on the results of the randomized controlled trials, a Japanese study is needed to resolve local problems.

Cancer screening programs in Japan: Progress and challenges.

National screening programs for gastric, colorectal, lung, breast, and cervical cancers are offered in Japan. The initial introduction of cancer screening programs was decided based on experts' opinions. Since 2003, the research groups funded by the National Cancer Center have published screening guidelines for gastric, colorectal, lung, prostate, cervical, and breast cancers. Although such guidelines have increasingly contributed to promoting evidence-based screening, it is still insufficient. Cancer screenings have mainly been provided in communities and workplaces. Compared with the average of OECD countries, participation rates in breast and cervical cancer screening are lower. Participation rates cannot be accurately calculated due to a lack of comprehensive cancer screening registries at the national level. Alternatively, estimates are derived from questionnaire surveys conducted on randomly selected samples from the national population. The quality assurance system has been limited to community-based screening and was not adapted to workplace screening until 2018. While there is a long history of cancer screening, the complex program delivery system might be a barrier to increasing the participation rate. Continued efforts are necessary to offer evidence-based cancer screening and establish an effective quality assurance system.

Sensitivity of endoscopic screening for gastric cancer by the incidence method.

Although radiographic screening for gastric cancer has been conducted in Japan, it is anticipated that endoscopy will become a new screening method because of its high detection rate. The sensitivities of endoscopic and radiographic screening were calculated by the detection method and the incidence method based on the results of community-based screening in Japan. There were 56,676 screenings for gastric cancer using endoscopy and radiography from April 2002 to March 2007 in Yonago, Japan. The target age group was from 40 to 79 years. Screen-detected and interval cancers were investigated based on a screening database linked to the Tottori Cancer Registry. All gastric cancers diagnosed within 1 year after a negative screen were considered interval cancers. Based on the screening history, these were divided into prevalence screening and incidence screening. Prevalence screenings included 7,388 for endoscopic screening and 5,410 for radiographic screening, whereas incidence screenings included 18,021 for endoscopic screening and 11,417 for radiographic screening. The sensitivity of prevalence screening calculated by the incidence method was 0.886 (95% confidence interval [CI] = 0.698-0.976) for endoscopic screening and 0.831 (95% CI = 0.586-0.964) for radiographic screening; however, the difference was not significant (p = 0.626). The sensitivity of incidence screening calculated by the incidence method was 0.954 (95% CI = 0.842-0.994) for endoscopic screening and 0.855 (95% CI = 0.637-0.970) for radiographic screening (p = 0.177). Endoscopic screening for gastric cancer had a higher sensitivity than radiographic screening by the incidence method in both screening rounds. However, further study is needed to evaluate mortality reduction and to estimate overdiagnosis with endoscopic screening for gastric cancer.