Double immunochemical screening test (hemoglobin and albumin) for the detection of occult intestinal bleeding

[Controversial issues in colorectal screening in Hungary: conflict of clinical and public health viewpoints]

In Hungary, mortality rates from colorectal cancer are dramatically high, therefore the reduction by population screening as a public health measure is considered as one of the priorities of National Public Health Program. In the beginning, a human-specific immunological test was applied in the "model programs", as a screening tool, to detect the occult blood in the stool; compliance was 32% in average. However, the objectives of the model programs have not been achieved, because, among other reasons, a debate on the method of choice and the strategy to follow have divided the professional public opinion. In this study the debated issues are critically discussed, being convinced that, at present, population screening seems to be the most promising way to alleviate the burden of colorectal cancer.

Use of multiple reaction monitoring for multiplex analysis of colorectal cancer-associated proteins in human feces

Colorectal cancer (CRC) is the second most common cause of cancer-related deaths worldwide with an annual incidence of almost a million cases and an annual mortality around 500,000. The fecal occult blood test is currently the first line method for CRC screening, but has unacceptably low sensitivity and specificity. Improved screening tests are therefore urgently required for early-stage CRC screening when therapy is most likely to be effective. We describe a discovery-based proteomics hypothesis using orthogonal multi-dimensional fractionation (1-D SDS-PAGE, RP-HPLC, size exclusion chromatography) to mine deep into the fecal proteome for the initial discovery process, which generated a library containing 108 human fecal proteins with the associated peptide and MS/MS data. These data were then used to develop and optimize a multiplex multiple reaction monitoring assay for 40 non-redundant human proteins present in the feces. To show proof of principal for clinical analysis, multiplex screening of these 40 proteins was carried out on fecal samples from eight CRC patient and seven normal volunteers. We identified 24 proteins consistently found in all samples and nine proteins found only in the CRC patients, showing the potential of this approach for the analysis of potential CRC biomarkers. Absolute quantitation using C-terminal isotopically labeled synthetic peptides corresponding to hemoglobin and carcinoembryonic antigen 5 was also performed.

The disease burden of colorectal cancer in Hungary

The aim of the paper is to give an overview of the epidemiology, treatment pattern and quality, as well as policy issues and disease burden of colorectal cancer (CRC) in Hungary. Colorectal cancer is the second most common cause of cancer-related death in both males and females in Hungary. The Hungarian Cancer Registry collects data on the epidemiological characteristics of CRC. Two pilot programmes (1997/1998 and 2003/2004) were conducted for population-based screening of CRC using both immunological and guaiac faecal occult blood testing (FOBT). The National Health Insurance Fund Administration (NHIFA) spends altogether <euro> 38.9 million a year on the treatment of CRC. It is hoped that the introduction of an accepted and cost-effective screening programme for CRC can reduce the high CRC burden in Hungary.

Colorectal cancer screening policy in Hungary

We read with great interest the excellent paper of Gutiérrez-Ibarluzea et al. on the review of current policies of screening for colorectal cancer in European countries (12).Colorectal cancer screening has been a hot topic in health technology assessment and medical decision making (13;15;18). The study by Gutiérrez-Ibarluzea and colleagues focused mainly on the “old” fifteen member states of the European Union; however, colorectal cancer represents a large epidemiological (3;11) and economic (4) burden for the society and the healthcare financing agency in Eastern European countries. We would like to highlight some important aspect of colorectal cancer screening in Hungary.

[The state of the colorectal screening in Hungary: lessons of the pilot programs]

In Hungary, colorectal cancer is the second most common malignant disease. Due to its natural history, colorectal cancer is particularly suitable for screening. At present, epidemiological evidences of the effectiveness of detection of the symptomless colorectal cancer and its precursors are only available for the demonstration of fecal occult blood, endoscopic methods are also in use. For mass screening, fecal occult blood tests are recommended. Guaiac-type chemical methods are widely criticized because of the lack of specificity. Out of the emerging technologies, immunochemical methods based on the antigenicity of blood proteins (hemoglobin) seem to be the most suitable. In the model programmes organized in the frame of the National Public Health Programme, an immunochemical method using two blood proteins (hemoglobin and albumin) have been used. The compliance was not more than 30-45%. About one-third of those with positive blood test refused colonoscopy. The programmes revealed a great number of adenomatous polyps and early cancers, and in the way, the effectiveness of the method has been proved. The model programmes are still continued. Before the continuous and gradual extension of colorectal screening, the validity of the specific method needs to be tested and proved in order to be recognized as a routine procedure for screening. There is a need to test the feasibility of total colonoscopy, however, to this effect the colonoscopic capacity in the country has to be further developed.

Early detection for colorectal cancer: new aspects in fecal occult blood screening

The authors report on promising diagnostic methods of occult intestinal bleeding and discusses the potential new strategy of early detection of colorectal carcinomas in respect to old and new diagnostic measures available. Because of the limited sensitivity and specificity of classical methods used for the demonstration of occult fecal blood, the authors recommend the introduction of new techniques and markers in screening practice. It is presumed that new discoveries in molecular biology will improve the accuracy of early colorectal cancer prevention. Their implementation into routine screening, however, will not take place in the near future. Until their realization, improved screening efficacy is expected from the use of more specific and sensitive blood tests.

Laboratory study on occult gastrointestinal bleedings: differential diagnostic method for the parallel study of intact and fragmented hemoglobin

The authors produced various degradation products of human hemoglobin. With the aid of immune sera raised against native hemoglobin and their fragments, we examined the antigenicity of the intact molecule and fragments as well as the specificity and reactivity of the immune sera used. Since conventional guaiac-type reactions make no distinction between the different hemoglobin molecules and the methods described in recent years' publications only with immune sera raised against native intact hemoglobin, the demonstration of occult fecal blood has not reached the desired rate of efficacy in clinical practice. The authors recommend the introduction of a simple differential diagnostic methods suitable for the parallel examination of intact and fragmented hemoglobin.