The effectiveness of cancer screening has been established by intervention studies, such as randomized controlled trials (RCTs) and observational studies. An optimally designed RCT can minimize various biases and present more reliable results compared with an observational study.
The progress of diagnostic technology in the medical field has exponentially accelerated with advances in the performance of semiconductor chips. RCTs require observations taken over a long period to obtain final results. As such, recommendations for cancer screening, based on assessments by RCTs, might not keep pace with the development of diagnostic applications. Furthermore, the evidence presented by an RCT is valid only under certain assumptions; therefore, extrapolating data for a different condition is difficult and likely to be inaccurate.
Under such circumstances, microsimulation could estimate data for which we do not have any confirmed evidence. However, data from reliable conventional studies, e.g. RCTs and observational studies, remain essential because microsimulations are built on evidence from studies in the real world. An accurate simulation model should be based on unbiased evidence reported by multiple optimally designed studies. Thus, a study method to assess cancer screenings, employing a microsimulation model along with conventional design, should be formulated.

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ABC classification is now performed to assess gastric cancer risk, and the stratification is based on pepsinogen levels and the Helicobacter pylori antibodies titer. In this study, we enrolled 750 individuals who underwent upper gastrointestinal endoscopy as part of a medical checkup. Serum pepsinogen levels were measured by SphereLight Wako system. Antibodies to H. pylori were also measured by both the new SphereLight Wako kit and E-plate kit. Positive rates of H. pylori antibody obtained from SphereLight Wako and E-plate kit were 28.5% and 25.2%, respectively. ABC classification by SphereLight Wako showed larger Groups B and C, and smaller Groups A and D in comparison with that by E-plate.
Disagreement of positive decision measured by SphereLight Wako and E-plate kit was accepted in 27 individuals. Positive decisions used by SphereLight Wako were observed in most cases (26/27) while those were negative by E-plate kit. Furthermore, 22 of 27 E-plate kit negative individuals were under cut-off value (3-9 U/mL).
Pepsinogen levels were also used to screen for atrophic gastritis of grade C-2 or worse (Kimura and Takemoto endoscopic classification) among individuals in Group A with the SphereLight Wako stratification. This reassessment could effectively decrease the rate of atrophic gastritis in Group A (from 5.8% to 3.0%).
In conclusion, SphereLight Wako system might contribute to the accuracy of ABC classification. The management of Group A (both negative cases for antibody and pepsinogen test method) still needs attention because atrophic gastritis cannot be completely excluded by only pepsinogen levels.

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Helicobacter pylori (H. pylori) infection has been reported as an established risk factor for atrophic gastritis and gastric cancer. Previous epidemiological studies have shown a relationship between chronic atrophic gastritis and food intake in H. pylori-infected subjects. Nevertheless, the role of dietary nutrient composition in the progression of chronic atrophic gastritis remains unclear. In this case-control study, we analyzed the compositions of various dietary nutrients and determined risk factors for the progression of chronic atrophic gastritis among H. pylori-infected subjects.
A total of 4,330 subjects aged 35-69 years participated in a baseline survey of the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study in Kyoto between June 2011 and November 2012. Among them, 1,251 subjects (435 men and 816 women) were serologically positive for H. pylori immunoglobulin G (IgG) antibody. From these subjects, this study enrolled 296 H. pylori-IgG-positive women and confirmed their nutrient intake from dietary history questionnaires. Logistic regression analysis based on tertile categories of subjects revealed that consumption of calcium (intermediate: odds ratio (OR) = 0.52, 95% CI = 0.28-0.96; high: OR = 0.52, 95% CI = 0.27-0.99; [P for trend = 0.02]) and polyunsaturated fatty acid (intermediate: OR = 0.41; 95% CI = 0.21-0.76; [P for trend = 0.05]) significantly decreased the risk of chronic atrophic gastritis after adjustment for age, smoking, alcohol consumption, taking vitamin tablets, and total energy intake. These data suggest that a specific composition of dietary nutrients may play a role in the development of chronic atrophic gastritis after H. pylori infection.

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Diagnosis of infection based on the classifications of Nakajima et al. was performed using X-ray films of patients examined after H. pylori eradication therapy. The diagnosis was uninfected in 14.5%, prior infection in 48.9%, and current infection in 36.6%. A trend toward a diagnosis of no infection was seen in patients <55 years old at the time of eradication and patients with background diseases of gastritis or duodenal ulcer or scarring. A trend toward a diagnosis of current infection was seen in patients with background diseases of gastric ulcer or scarring. The diagnosis based on X-ray examination was current or prior infection in many patients for whom a high risk of gastric cancer was suspected after eradication. Some, however, were diagnosed as uninfected and the risk was judged as low. Patients who have undergone eradication often show false-positive results when infection is diagnosed using X-ray films only. The number of patients who have undergone eradication is expected to increase in the future, and a test system in which the history of eradication is checked and results are considered accordingly appears warranted.

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We assessed whether serum levels of pepsinogen (PG) measured after eradication of H. pylori could be a marker of gastric atrophy before eradication. Serum levels of PG I/II and anti-H. pylori IgG antibody were measured before and after eradication of H. pylori in a total of 193 patients who underwent gastroscopy. Gastric atrophy was evaluated according to the Kimura-Takemoto classification. When subjects were classified by the results of the PG method, PG I and PG I/II ratios after eradication could distinguish the PG method-positives from negatives. When the cut of 36.5 ng/ml was used, the validity for the estimation of positive or negative for PG method was 74.2%. This criterion correlated well with the gastric atrophy based on Kimura-Takemoto classification. Therefore, serum PGs measured after eradication of H. pylori could reflect gastric atrophy before eradication.

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We experienced two cases of adenocarcinoma at the gastroesophageal junction shortly after a medical checkup. Following the decreased rate of Helicobacter pylori (H. pylori) infection in the younger generation and active adoption of H. pylori elimination, the incidence of adenocarcinoma at the gastroesophageal junction is thought to increase. In the new guideline for the medical checkup for gastric cancer, gastroendoscopy is recommended as one of the countermeasures/optional medical checkup, thus demand for endoscopic examination has heightened. Increasing awareness of the gastroesophageal junction as an important high-risk location for cancer as well as thorough and detailed observation without overlooking this aspect are needed.

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We described a case of the proximal jejunal cancer diagnosed with transnasal EGD. 55-year old Japanese woman visited to our department with complaining nausea and appetite loss. The plain abdominal X ray and CT showed fullness of the stomach, dilatation of the duodenum and stricture of the proximal jejunum. We performed transnasal EGD without sedation. After gastroduodenal observation, when we inserted a super stiff guide wire into the biopsy channel until 20cm distal end of the scope, we were able to advance the scope until the proximal jejunum. We pointed out the near-circumferential mass like type 2 in about 5 cm anal side from duodenojejunal junction. We diagnosed it as the jejunal adenocarcinoma with biopsy. Since it is not easy to observe the distal duodenum and the proximal jejunum with a conventional upper gastrointestinal endoscopy, we often need to use a capsule endoscopy or balloon endoscopy. However, we were able to diagnose the lesion with only transnasal EGD by a little ingenuity.

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