Molecular Typing and Clinical Characteristics of Synchronous Multiple Primary Colorectal Cancer

• DOI: 10.1001/jamanetworkopen.2022.43457
• Publication Date: 2022-11-23T16:33:49Z
• Authors: Yandong Zhao; Jingjing Wu; Fengyun Pei; Yanxiang Zhang; Shaomei Bai; Lishuo Shi; Xiang Zhang; Jingjiao Ma; Ximeng Zhao; Tonghui Ma; Jianping Wang; Meijin Huang; Xinjuan Fan; Jun Huang
• Keywords: Microsatellite Instability; Lynch Syndrome

Importance Synchronous multiple primary colorectal cancer (sMPCC) is clinically rare, but its incidence has increased over the past decade. However, little known about molecular and clinical features of sMPCC, which may differ from those single (SPCRC). Objective To evaluate characteristics pathogenic variations in lesions typing sMPCC. Design, Setting, Participants From November 2012 to April 2021, patients with (CRC) treated at Sixth Affiliated Hospital Sun Yat-sen University were enrolled this cohort study. Follow-up ended on January 31, 2022. Main Outcomes Measures The outcome was mismatch repair (MMR) status each lesion all examined using immunohistochemistry (IHC). Microsatellite instability (MSI) tumor mutation burden (TMB) also calculated. Results A total 13 276 CRC enrolled, 239 sMPCC (mean [SD] age, 63.3 [12.2] years; 173 men [72.4%]) available data evaluated. Seventy-eight 94 SPCRC underwent next-generation sequencing (NGS)–based testing. deficient MMR (dMMR)/MSI-H frequencies significantly higher than SPCRC, confirmed by both IHC (50 vs 872 037 patients) NGS (17 78 5 patients). According MMR/MSI different they further divided into 3 subgroups: dMMR/MSI-H, dMMR/MSI-H proficient (pMMR)/microsatellite stability (MSS), pMMR/MSS. EGFR PIK3CA variants more common, whereas TP53 less prevalent SPCRC. Moreover, associated MSI rather Conclusions Relevance In study that These findings suggest can be classified subgroups according lesion, might applied guide personalized therapies for better disease management.