Ondrej Majek

Bio: Ondrej Majek is an academic researcher from Masaryk University. The author has contributed to research in topics: Population & Colonoscopy. The author has an hindex of 11, co-authored 27 publications receiving 484 citations. Previous affiliations of Ondrej Majek include Charles University in Prague.

Mammographic screening programmes in Europe: organization, coverage and participation

Abstract: Objectives To summarize participation and coverage rates in population mammographic screening programmes for breast cancer in Europe. Methods We used the European Network for Information on Cancer (EUNICE), a web-based data warehouse (EUNICE Breast Cancer Screening Monitoring, EBCSM) for breast cancer screening, to obtain information on programme characteristics, coverage and participation from its initial application in 10 national and 16 regional programmes in 18 European countries. Results The total population targeted by the screening programme services covered in the report comprised 26.9 million women predominantly aged 50-69. Most of the collected data relates to 2005, 2006 and/or 2007. The average participation rate across all programmes was 53.4% (range 19.4-88.9% of personally invited); or 66.4% excluding Poland, a large programme that initiated personal invitations in 2007. Thirteen of the 26 programmes achieved the European Union benchmark of acceptable participation (.70%), nine achieved the desirable level (.75%). Despite considerable invitation coverage across all programmes (79.3%, range 50.9-115.2%) only 48.2% (range 28.4-92.1%) of the target population were actually screened. The overall invitation and examination coverage excluding Poland was 70.9% and 50.3%, respectively. Conclusions The results demonstrate the feasibility of European-wide screening monitoring using the EBCSM data warehouse, although further efforts to refine the system and to harmonize standards and data collection practices will be required, to fully integrate all European countries. The more than three- fold difference in the examination coverage should be taken into account in the evaluation of service screening programmes.

Oral contraceptives and risk of ovarian and breast cancers in BRCA mutation carriers: a meta-analysis

Abstract: Prophylactic salpingo-oophorectomy is currently the only effective strategy available for decreasing ovarian cancer risk in BRCA1/2 mutation carriers. Significantly decreased risk of ovarian cancer associated with the use of combined oral contraceptives (COCs) was shown in the general population, which could be an alternative approach for those who do not accept risk-reducing surgery. Cohort, case-control and case-case studies published in English up to December 2009 reporting the association of ovarian or breast cancer risk with the use of COCs and presenting BRCA status were selected for meta-analysis. Meta-analysis of three case-control studies showed a significant risk reduction of ovarian cancer in BRCA1/2 mutation carriers who were associated with any past COC use (odds ratio [OR]: 0.57; 95% CI: 0.47-0.70; p < 0.001) and significant trend by duration of COC use (OR: 0.95; 95% CI: 0.93-0.97; p < 0.001). No significant increase in breast cancer risk associated with COC use has been found in case-control studies in BRCA1 (OR: 1.08; p = 0.250), in BRCA2 (OR: 1.03; p = 0.788) mutation carriers or in case-case studies in BRCA1/2 carriers (OR: 0.80; p = 0.147). Significantly increased risk of breast cancer was only shown on a subset of cohort studies in BRCA1 mutation carriers (OR: 1.48; 95% CI: 1.14-1.92). In conclusion, meta-analysis confirmed significantly decreased ovarian cancer risk in BRCA1/2 mutation carriers associated with the use of COCs comparable to the relative extent shown in the general population. Data on the risk of breast cancer associated with COC use in BRCA mutation carriers are heterogeneous and results are inconsistent. COCs can be considered as an alternative strategy in the chemoprevention of ovarian cancer in BRCA1 mutation carriers who do not accept prophylactic salpingo-oophorectomy above the age of 30 years.

Colorectal cancer screening: 20 years of development and recent progress

Abstract: Colorectal cancer (CRC) is the second most common cancer in Europe and its incidence is steadily increasing. This trend could be reversed through timely secondary prevention (screening). In the last twenty years, CRC screening programs across Europe have experienced considerable improvements (fecal occult blood testing; transition from opportunistic to population based program settings). The Czech Republic is a typical example of a country with a long history of nationwide CRC screening programs in the face of very high CRC incidence and mortality rates. Each year, approximately 8000 people are diagnosed with CRC and some 4000 die from this malignancy. Twenty years ago, the first pilot studies on CRC screening led to the introduction of the opportunistic Czech National Colorectal Cancer Screening Program in 2000. Originally, this program was based on the guaiac fecal occult blood test (FOBT) offered by general practitioners, followed by colonoscopy in cases of FOBT positivity. The program has continuously evolved, namely with the implementation of immunochemical FOBTs and screening colonoscopy, as well as the involvement of gynecologists. Since the establishment of the Czech CRC Screening Registry in 2006, 2405850 FOBTs have been performed and 104565 preventive colonoscopies recorded within the screening program. The overall program expanded to cover 25.0% of the target population by 2011. However, stagnation in the annual number of performed FOBTs lately has led to switching to the option of a population-based program with personal invitation, which is currently being prepared.

Complex Reporting of the COVID-19 Epidemic in the Czech Republic: Use of an Interactive Web-Based App in Practice.

Abstract: Background: The beginning of the coronavirus disease (COVID-19) epidemic dates back to December 31, 2019, when the first cases were reported in the People’s Republic of China. In the Czech Republic, the first three cases of infection with the novel coronavirus were confirmed on March 1, 2020. The joint effort of state authorities and researchers gave rise to a unique team, which combines methodical knowledge of real-world processes with the know-how needed for effective processing, analysis, and online visualization of data. Objective: Due to an urgent need for a tool that presents important reports based on valid data sources, a team of government experts and researchers focused on the design and development of a web app intended to provide a regularly updated overview of COVID-19 epidemiology in the Czech Republic to the general population. Methods: The cross-industry standard process for data mining model was chosen for the complex solution of analytical processing and visualization of data that provides validated information on the COVID-19 epidemic across the Czech Republic. Great emphasis was put on the understanding and a correct implementation of all six steps (business understanding, data understanding, data preparation, modelling, evaluation, and deployment) needed in the process, including the infrastructure of a nationwide information system; the methodological setting of communication channels between all involved stakeholders; and data collection, processing, analysis, validation, and visualization. Results: The web-based overview of the current spread of COVID-19 in the Czech Republic has been developed as an online platform providing a set of outputs in the form of tables, graphs, and maps intended for the general public. On March 12, 2020, the first version of the web portal, containing fourteen overviews divided into five topical sections, was released. The web portal’s primary objective is to publish a well-arranged visualization and clear explanation of basic information consisting of the overall numbers of performed tests, confirmed cases of COVID-19, COVID-19-related deaths, the daily and cumulative overviews of people with a positive COVID-19 case, performed tests, location and country of infection of people with a positive COVID-19 case, hospitalizations of patients with COVID-19, and distribution of personal protective equipment. Conclusions: The online interactive overview of the current spread of COVID-19 in the Czech Republic was launched on March 11, 2020, and has immediately become the primary communication channel employed by the health care sector to present the current situation regarding the COVID-19 epidemic. This complex reporting of the COVID-19 epidemic in the Czech Republic also shows an effective way to interconnect knowledge held by various specialists, such as regional and national methodology experts (who report positive cases of the disease on a daily basis), with knowledge held by developers of central registries, analysts, developers of web apps, and leaders in the health care sector.

Prognostic Value of Scores Based on Malnutrition or Systemic Inflammatory Response in Patients With Metastatic or Recurrent Gastric Cancer

Abstract: Cancer patients are frequently affected by malnutrition and weight loss, which affects their prognosis, length of hospital stay, health care costs, quality of life and survival. Our aim was to assess the prognostic value of different scores based on malnutrition or systemic inflammatory response in 91 metastatic or recurrent gastric cancer patients considered for palliative chemotherapy at the Masaryk Memorial Cancer Institute. We investigated their overall survival according to the following measures: Onodera's Prognostic Nutritional Index (OPNI), Glasgow Prognostic Score (GPS), nutritional risk indicator (NRI), Cancer Cachexia Study Group (CCSG), as previously defined, and a simple preadmission weight loss. The OPNI, GPS, and CCSG provided very significant prognostic values for survival (log-rank test P value < 0.001). For example, the median survival for patients with GPS 0 was 12.3 mo [95% confidence interval (CI): 7.7-16.7], whereas the median survival for patients with GPS 2 was only 2.9 mo (95% CI: 1.9-4.8). A significantly worse survival of malnourished patients was also suggested by a multivariate model. The values of GPS, OPNI, and CCSG represent useful tools for the evaluation of patients' prognosis and should be part of a routine evaluation of patients to provide a timely nutrition support.

International evaluation of an AI system for breast cancer screening.

Abstract: Screening mammography aims to identify breast cancer at earlier stages of the disease, when treatment can be more successful1. Despite the existence of screening programmes worldwide, the interpretation of mammograms is affected by high rates of false positives and false negatives2. Here we present an artificial intelligence (AI) system that is capable of surpassing human experts in breast cancer prediction. To assess its performance in the clinical setting, we curated a large representative dataset from the UK and a large enriched dataset from the USA. We show an absolute reduction of 5.7% and 1.2% (USA and UK) in false positives and 9.4% and 2.7% in false negatives. We provide evidence of the ability of the system to generalize from the UK to the USA. In an independent study of six radiologists, the AI system outperformed all of the human readers: the area under the receiver operating characteristic curve (AUC-ROC) for the AI system was greater than the AUC-ROC for the average radiologist by an absolute margin of 11.5%. We ran a simulation in which the AI system participated in the double-reading process that is used in the UK, and found that the AI system maintained non-inferior performance and reduced the workload of the second reader by 88%. This robust assessment of the AI system paves the way for clinical trials to improve the accuracy and efficiency of breast cancer screening. An artificial intelligence (AI) system performs as well as or better than radiologists at detecting breast cancer from mammograms, and using a combination of AI and human inputs could help to improve screening efficiency.

Screening for Breast Cancer: U.S. Preventive Services Task Force Recommendation Statement

Abstract: This guideline from the USPSTF is based on current evidence on mammography, digital breast tomography, and supplemental screening for breast cancer. The recommendations apply to asymptomatic women ...

Colorectal cancer screening: a global overview of existing programmes

Abstract: Colorectal cancer (CRC) ranks third among the most commonly diagnosed cancers worldwide, with wide geographical variation in incidence and mortality across the world. Despite proof that screening can decrease CRC incidence and mortality, CRC screening is only offered to a small proportion of the target population worldwide. Throughout the world there are widespread differences in CRC screening implementation status and strategy. Differences can be attributed to geographical variation in CRC incidence, economic resources, healthcare structure and infrastructure to support screening such as the ability to identify the target population at risk and cancer registry availability. This review highlights issues to consider when implementing a CRC screening programme and gives a worldwide overview of CRC burden and the current status of screening programmes, with focus on international differences.