biostudies-literaturevan der Heide DMNCI NIH HHSNational Institutes of Health104-112https://www.ebi.ac.uk/biostudies/studies/S-EPMC8338754biostudies-literatureUnknown266<h4>Background</h4>Young adults with metastatic colorectal cancer (mCRC) may have higher rates of deficient mismatch repair (dMMR) than older patients. This study sought to assess patterns of MMR-testing and survival among young adult mCRC patients in the National Cancer Database (NCDB), hypothesizing that dMMR correlates with worse survival than in MMR-proficient (pMMR) patients.<h4>Methods</h4>Stage-IV colorectal cancers were identified in NCDB (2010-2016). Demographic and clinical features were compared between younger (age ≤ 30) and older mCRC patients and tested for association with overall survival. Stage-IV disease without other recorded metastatic sites defined peritoneal metastasis (PM). Fisher-exact tests compared proportions and Cox models tested association with overall survivaThe Journal of surgical researchMismatch Repair Status Correlates with Survival in Young Adults with Metastatic Colorectal Cancer.PMC8338754T32#CA148062T32 CA078586T32 CA148062T32#CA078586P01 CA217797Sherman SKTuraga KKChan CHFvan der Heide DMfalseMismatch Repair Status Correlates with Survival in Young Adults with Metastatic Colorectal Cancer.<h4>Background</h4>Young adults with metastatic colorectal cancer (mCRC) may have higher rates of deficient mismatch repair (dMMR) than older patients. This study sought to assess patterns of MMR-testing and survival among young adult mCRC patients in the National Cancer Database (NCDB), hypothesizing that dMMR correlates with worse survival than in MMR-proficient (pMMR) patients.<h4>Methods</h4>Stage-IV colorectal cancers were identified in NCDB (2010-2016). Demographic and clinical features were compared between younger (age ≤ 30) and older mCRC patients and tested for association with overall survival. Stage-IV disease without other recorded metastatic sites defined peritoneal metastasis (PM). Fisher-exact tests compared proportions and Cox models tested association with overall surviva2021-01-01T00:00:00Z2021 Oct2025-04-18T16:16:21.323Z2025-04-07T03:18:50.453ZS-EPMC83387543398988910.1016/j.jss.2021.03.040