Japanese Society of Medical Oncology Clinical Guidelines: Molecular Testing for Colorectal Cancer Treatment, Third Edition

The Japanese Society of Medical Oncology (JSMO) previously published 2 editions of the clinical guidelines: “Japanese guidelines for testing of KRAS gene mutation in colorectal cancer” in 2008 and “Japanese Society of Medical Oncology Clinical Guidelines: RAS (KRAS/NRAS) mutation testing in colorectal cancer patients” in 2014. These guidelines have contributed to the proper use of KRAS and RAS mutation testing, respectively. Recently, clinical utility, particularly for colorectal cancer (CRC) patients with BRAF V600E mutation or DNA mismatch‐repair (MMR) deficiency, has been established. Therefore, the guideline members decided these genetic alterations should also be involved. The aim of this revision is to properly carry out testing for BRAF V600E mutation and MMR deficiency in addition to RAS mutation. The revised guidelines include the basic requirements for testing for these genetic alterations based on recent scientific evidence. Furthermore, because clinical utility of comprehensive genetic testing using next‐generation sequencing and somatic gene testing of analyzing circulating tumor DNA has increasingly evolved with recent advancements in testing technology, we noted the current situation and prospects for these testing technologies and their clinical implementation in the revised guidelines.