Inclusion and exclusion criteria
tumor, CRC
TUMOR, METASTASIS, SECONDARY, ONCOLOGY, PATHOLOGY
Key inclusion criteria were listed as follows: consecutive patients with diagnosis of CRC and peritoneal metastasis by pathology, preoperative imaging for tumor staging, and Eastern Cooperative Oncology Group (ECOG) performance status of 0–2. Exclusion criteria included insufficient tumor tissue or peritoneal lavages, failure of NGS assays, missing data or follow-up and ineligible for cfDNA analysis.The primary objective was to evaluate the sensitivity and specificity of peritoneal cfDNA in diagnosis of PM. The secondary objectives included positive/negative predictive values, accuracy, genomic mutation profiles in peritoneal cfDNA and matched tumor tissues, the underlying pathways and prognostic roles. The sample size was set as 1:1 ratio with each 20 cases in both arms.