In consideration of the prevalence of Helicobacter pylori (Hp) infection, we introduced medical interview items on Hp with X-ray screening for gastric cancer. Among 1457 individuals who underwent X-ray screening for gastric cancer in Yamatotakada City in Nara prefecture between April and July 2011, 196 (13.4%) had a history of Hp testing and 92 (6.3%) had a history of Hp eradication based on the interviews. A comparison of medical interview results and X-ray findings of Hp infection showed that 51 of the 196 individuals (26.0%) had a discrepancy between the results. Considering the cases of incorrect memory among individuals, false-negative and false-positive serology results, and spontaneous eradication, X-ray findings may play a complementary role in confirming Hp infection. We plan to continue our investigation in order to determine optimal approaches for X-ray screening of gastric cancer in consideration of Hp infection.

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A quantitative immunochemical fecal occult blood test used for colon cancer screening aims to estimate the probability of colon cancer, and increase clinical confidence in the diagnosis. This study prepared a brief clinical prediction model to estimate an individual’s post-test probability of disease for those who tested positive in colon cancer screening conducted in Fukuoka City using a screening form for medical examinees and the quantitative fecal hemoglobin (Hb) concentration, and objectively identified that an increasing number of clinical predictors elevates the disease probability of colon cancer. Using the positive fecal occult blood test (two-day method) results at a concentration of >= 500 ng/ml for both days, no past medical examinations, the highest quantitative fecal Hb concentration of >= 1,000 ng/ml, blood feces, and >= 60 years old as clinical indicators, the probability of the disease was increased about 10-fold compared to a positive predictive value of 5.9%. The marked level of clinical confidence is expected to promote physicians’ activities to recommend and help motivate examinees to undergo a complete examination.

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The fecal occult blood test (FOBT) has been widely used as the main screening test for colorectal cancer (CRC). However, the efficacy of the FOBT is limited due to lower sensitivity for proximal CRC, as degradation of hemoglobin (Hb) in the colon is affected by the transit time of the stool. The hemoglobin-haptoglobin (Hb/Hp) complex is more stable than Hb alone in feces. Therefore, we performed a retrospective study, comprising 73 patients with CRC, 19 patients with colorectal adenoma, and 82 control subjects, to compare the performance of the Hb/Hp complex test with the FOBT. Hb/Hp complex and FOB were measured by BioNexia^® Hb/Hp complex (DIMA, Goettingen, Germany) and Magstream^® HemSP^® (Eiken Chemical, Tokyo), respectively. The specificity of the Hb/Hp complex test was significantly lower than the FOBT (65.9% vs. 97.6%, P < 0.001), whereas the sensitivity was significantly higher (83.6% [Hb/Hp complex] vs. 60.3% [FOBT]; P < 0.001). In addition, the sensitivity of the Hb/Hp complex test tended to be higher than the FOBT for proximal cancer, but was not significantly different. These results indicate that a cutoff value may be required for the Hb/Hp complex test to optimize and improve the specificity of the test.

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In order to drastically improve the detailed examination rate for strategic colorectal cancer examination in Japan, it is necessary to introduce CT colonography (CTC) as a detailed examination method for colorectal cancer examination, in addition to colonoscopy (CS) which is the conventional detailed examination method. In our study, a cleansing enema/contrast solution (3% Nif-C) was prepared by adding 60 ml of a water-soluble iodine-based contrast agent (Gastrografin^®) and water to an oral cleansing enema agent (Niflec^®) in solid (powder) form to a final amount of 2000 ml. The solution was compared with a Niflec solution. In terms of patient’s acceptability, more than half of the examined patients answered “easier to drink than the Niflec solution” or “as easy to drink as the Niflec solution.” Also, the Nif-C solution was comparable or superior to the Niflec solution in terms of cleansing enema effects. Regarding imaging effects essential for CTC, the CT level was found to be 200 HU or greater for any large intestine region upon CTC using the Nif-C solution. Thus, practically sufficient imaging effects were achieved. In conclusion, CTC with pretreatment involving a cleansing enema with oral administration of 3% Nif-C is superior to CS in terms of patient’s acceptability. In addition, at least in view of the overseas reports on CTC, there is no particular problem in terms of diagnostic accuracy. Thus, CTC is expected to resolve various problems related to colorectal cancer examination in Japan.

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