Analytical frameworks in colorectal cancer guidelines: development of methods for systematic reviews, their application and practical guidance for their use.

OBJECTIVES: Analytical frameworks are graphical representation of the key questions answered by a systematic review and can support the development of guideline recommendations. Our objectives were to a) conduct a systematic review to identify, describe and compare all analytical frameworks published as part of a systematic and guideline development process related to colorectal cancer (CRC), and b) to use this case study to develop guidance on how to conduct systematic reviews of analytical frameworks. METHODS: We developed a search strategy to identify eligible studies in Medline and Embase from 1996 until December 2020. We also manually searched guideline databases and websites to identify all guidelines and systematic reviews in CRC that used an analytical framework. We assessed the quality of the guidelines using the Appraisal of Guidelines for Research and Evaluation II tool. The systematic review was registered in International Prospective Register of Systematic Reviews, registration CRD42020172117. RESULTS: We screened 34,505 records and identified 1,166 guidelines and 3,127 systematic reviews on CRC of which five met our inclusion criteria. These five publications included four analytical frameworks in colorectal cancer (one update). We also describe our methodological approach to systematic reviews for analytical frameworks and underlying concepts for developing analytical framework using a bottom-up or top-down approach. CONCLUSION: Few guidelines and systematic reviews are utilizing analytical frameworks in the development of recommendations. Development of analytical frameworks should begin with a systematic search for existing analytical frameworks and follow a structured conceptual approach for their development to support guideline recommendations. Our methods may be helpful in achieving these objectives.

ECVAM and new technologies for toxicity testing.

The development of alternative empirical (testing) and non-empirical (non-testing) methods to traditional toxicological tests for complex human health effects is a tremendous task. Toxicants may potentially interfere with a vast number of physiological mechanisms thereby causing disturbances on various levels of complexity of human physiology. Only a limited number of mechanisms relevant for toxicity ('pathways' of toxicity) have been identified with certainty so far and, presumably, many more mechanisms by which toxicants cause adverse effects remain to be identified. Recapitulating in empirical model systems (i.e., in vitro test systems) all those relevant physiological mechanisms prone to be disturbed by toxicants and relevant for causing the toxicity effect in question poses an enormous challenge. First, the mechanism(s) of action of toxicants in relation to the most relevant adverse effects of a specific human health endpoint need to be identified. Subsequently, these mechanisms need to be modeled in reductionist test systems that allow assessing whether an unknown substance may operate via a specific (array of) mechanism(s). Ideally, such test systems should be relevant for the species of interest, i.e., based on human cells or modeling mechanisms present in humans. Since much of our understanding about toxicity mechanisms is based on studies using animal model systems (i.e., experimental animals or animal-derived cells), designing test systems that model mechanisms relevant for the human situation may be limited by the lack of relevant information from basic research. New technologies from molecular biology and cell biology, as well as progress in tissue engineering, imaging techniques and automated testing platforms hold the promise to alleviate some of the traditional difficulties associated with improving toxicity testing for complex endpoints. Such new technologies are expected (1) to accelerate the identification of toxicity pathways with human relevance that need to be modeled in test methods for toxicity testing (2) to enable the reconstruction of reductionist test systems modeling at a reduced level of complexity the target system/organ of interest (e.g., through tissue engineering, use of human-derived cell lines and stem cells etc.), (3) to allow the measurement of specific mechanisms relevant for a given health endpoint in such test methods (e.g., through gene and protein expression, changes in metabolites, receptor activation, changes in neural activity etc.), (4) to allow to measure toxicity mechanisms at higher throughput rates through the use of automated testing. In this chapter, we discuss the potential impact of new technologies on the development, optimization and use of empirical testing methods, grouped according to important toxicological endpoints. We highlight, from an ECVAM perspective, the areas of topical toxicity, skin absorption, reproductive and developmental toxicity, carcinogenicity/genotoxicity, sensitization, hematopoeisis and toxicokinetics and discuss strategic developments including ECVAM's database service on alternative methods. Neither the areas of toxicity discussed nor the highlighted new technologies represent comprehensive listings which would be an impossible endeavor in the context of a book chapter. However, we feel that these areas are of utmost importance and we predict that new technologies are likely to contribute significantly to test development in these fields. We summarize which new technologies are expected to contribute to the development of new alternative testing methods over the next few years and point out current and planned ECVAM projects for each of these areas.

ECVAM's response to the changing political environment for alternatives: consequences of the European Union chemicals and cosmetics policies.

The European Centre for the Validation of Alternative Methods (ECVAM) has restructured its services by directly targeting the animal tests that need to be replaced. In view of the short time-lines for making available and implementing validated methods, ECVAM is offering to steer the process by bringing together the inputs of stakeholders and encouraging the early involvement of regulators. In essence, steering groups formed by ECVAM senior staff, and complemented with external experts, will carry out the project management and will coordinate the various inputs.