232 Chapter 11 analyses, which capture the complexity of diseases on multiple levels. As sequencing technologies have become less expensive, tumor genotyping has become standard practice for metastatic CRC (mCRC) 14, 16. As a result, clinicians now often have information on the mutational status of several oncogenes, and investigating molecular changes in primary tumors concerning metastatic potential is becoming more common 16, 17. We hypothesize that specific biomarkers, based on DNA/RNA alterations identified in the primary tumor, might characterize colorectal PM patients. Once identified, these alterations can be incorporated into a prediction tool to estimate the risk of PM development, prognosis, and be helpful in choosing the appropriate treatment options 12, 13. In this paper, the authors aim to systematically review the available literature to: (1) create an overview of previously investigated DNA and RNA alterations in the primary tumor correlated to colorectal PM and (2) investigate which gene mutations are of potential biomarker value and should be further studied. This study focuses solely on CRC (stages I–IV) and does not include other types of neoplasms. METHODS Study Protocol and Registration This systematic review was conducted and reported according to the guidelines of the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) 18. The study protocol was registered at PROSPERO (registration number CRD42021297366). Search and Information Sources A literature search was performed on the 6 January 2022 and repeated before submission on the 3rd of November 2022. PubMed, Embase, the Cochrane Library, and CINAHL Database were searched with the use of MeSH-, Emtree-, and free terms including ‘’colorectal neoplasms’’, ’’peritoneal neoplasms’’, ‘’mutations’’, ‘’genetic testing’’, ‘’genetic association studies’’, ‘’gene expression profiling’’ and ‘’biomarkers, tumor’’ and additional search terms such as ‘’colorectal’’, ‘’adenocarcinoma’’, ‘’carcinomatosis’’ and ‘’predictive biomarker’’. The full search strategy is displayed in Appendix A. A professional clinical librarian was involved to ensure an appropriate search strategy. Reference lists of all relevant publications were hand-searched for additional studies. This method of cross-referencing was continued until no further relevant publications were identified. Selection Process Inclusion and Exclusion Criteria Articles containing original data concerning genomic analyses on patients with CRC and PM were considered eligible. The primary outcome measure was specific mutations on the DNA or RNA level in the primary colorectal tumor that might be associated with PM. Studies were
RkJQdWJsaXNoZXIy MTk4NDMw