Background : Detection of diseases via exhaled breath remains an attractive idea despite persisting gaps in understanding the origin of volatile organic compounds (VOCs) and their relationship with the disease of interest. Data on factors potentially influencing the results of breath analysis remain rather sparse and often controversial. In this study, we aimed to investigate the associations of common VOCs in exhaled breath of average-risk individuals with socio-demographic and lifestyle factors, medical conditions as well as diet. Methods : Alveolar breath samples of 1447 men and women were collected in the morning after fasting and were analyzed using gas-chromatography linked with mass-spectrometry. Study participants were 40–64 years old, cancer-free, with overall good health status. The associations between selected VOCs and various factors determined from the questionnaire data were assessed using two-part-Wilcoxon test and Jonckheere–Terpstra trend test. Results : Fifteen VOCs where each of them was detected in at least 80% of the study population were included in this analysis. Statistically significant associations with various VOCs were demonstrated for gender and consumption of certain foods, such as coffee, leeks and garlic, while smoking was not associated with any of the analyzed compounds. Conclusion : Factors potentially modifying the composition of exhaled breath, such as dietary factors, deserve careful attention in the design and analysis of studies accessing the use of VOCs as diagnostic markers.

Colorectal cancer (CRC) is a leading cause of cancer morbidity and mortality. Dysbiosis in the gut microbiota may be associated with CRC. This systematic review focuses on differences in gut microbial community between people diagnosed with CRC or adenoma and healthy individuals using fecal samples, emphasizing non-invasive fecal microbiome models for CRC early diagnosis. Nineteen studies were identified in a systematic literature search of Pubmed, Web of Science and ScienceDirect. Several bacteria were reported to differ in abundance between CRC and adenoma cases and healthy controls, with Fusobacterium the most common. Fecal multi-bacterial predictive models used to distinguish CRC patients from healthy controls had reported areas under the receiver operating curve (AUCs) in external validation populations of 0.68–0.77. Though advanced sequencing techniques could in the future complement current non-invasive methods for CRC early detection, more studies with high statistical power, comparable and reproducible methods and external validation of predictive models are needed.

PROBASE is a population‐based, randomized trial of 46 495 German men recruited at age 45 to compare effects of risk‐adapted prostate cancer (PCa) screening starting either immediately at age 45, or at a deferred age of 50 years. Based on prostate‐specific antigen (PSA) levels, men are classified into risk groups with different screening intervals: low‐risk (3 ng/ml, recommendation for immediate biopsy). Over the first 6 years of study participation, attendance rates to scheduled screening visits varied from 70.5% to 79.4%, depending on the study arm and risk group allocation, in addition 11.2% to 25.4% of men reported self‐initiated PSA tests outside the PROBASE protocol. 38.5% of participants had a history of digital rectal examination or PSA testing prior to recruitment to PROBASE, frequently associated with family history of PCa. These men showed higher rates (33% to 57%, depending on subgroups) of self‐initiated PSA testing in‐between PROBASE screening rounds. In the high‐risk groups (both arms), the biopsy acceptance rate was 64% overall, but was higher among men with screening PSA ≥4 ng/ml (>71%) and with PIRADS ≥3 findings upon multiparameter magnetic resonance imaging (mpMRI) (>72%), compared with men with PSA ≥3 to 4 ng/ml (57%) or PIRADS score ≤ 2 (59%). Overall, PROBASE shows good acceptance of a risk‐adapted PCa screening strategy in Germany. Implementation of such a strategy should be accompanied by a well‐structured communication, to explain not only the benefits but also the harms of PSA screening.

The aim of this study is to report key performance estimates from the ten years of a population-based prostate cancer screening programme in Lithuania. Retrospective analysis of screening activities recorded in 2006–2015 among men aged 50–74 years was performed. We estimated screening coverage, cancer detection rate, compliance to biopsy, and positive predictive values in each screening round inside and outside the target population. In the first 10 years of screening, 16,061 prostate cancer cases were registered within the screening programme, 10,202 were observed among screened men but reported outside the screening programme, and 1455 prostate cancers were observed in a screening-naïve population. Screening cover reached up to 45.5% of the target population in the recent rounds. The proportion of prostate specific antigen (PSA) test-positive men decreased from 16.9% in 2006 to 10.7% in 2014–2015. Up to 40.0% of PSA test-positive men received a biopsy, of whom 42.0% were positive for prostate cancer. The cancer detection rate was 10.4−15.0% among PSA test-positives and 1.4–1.9% among screened individuals. Screening participants were more likely to be diagnosed with organ-confined disease as compared to non-participants. Despite the unorganized screening practices being employed and low coverage per screening round, 70% of the target population were screened at least once in the first 10 years of screening.

Background . Regular screening for gastric cancer (GC) is based on invasive upper gastrointestinal endoscopy and is limited to few high-incidence countries. As GC is a major cause of cancer death worldwide, a non-invasive, simple screening test is of value. We assessed the prevalence of preclinical GC and the corresponding numbers needed to screen (NNS) to detect GC cases both without and with preselection using breath tests from the literature in various populations. Methods . Using age- and sex-specific GC incidence data and rates of transition from preclinical to clinical GC, we estimated the prevalences of preclinical GC worldwide in populations aged 50–74 years, and we evaluated the accuracy of breath testing for GC detection based on published studies. We then derived the expected positive predictive values for breath testing in populations with different preclinical GC prevalences. Results . Four studies reporting the sensitivity and specificity of breath tests were identified, and summary estimates of 83% sensitivity and 91% specificity were derived by meta-analysis. The estimates of the overall prevalence of preclinical GC were <0.5% in men and <0.2% in women aged 50–74 years across different regions of the world. The positive predictive values, the prevalence among breath test positive people, were approximately nine-fold higher in all populations, resulting in an approximately nine-fold lower NNS to detect one GC case when breath tests were used for preselection for screening. Conclusion . Given the low prevalence of preclinical GC, non-invasive breath tests show promise for making screening more efficient. Further validation of breath tests and evidence on the rates of transition from preclinical to clinical GC are needed to validate the breath test approach.