The significance of small lymph nodes on CT for advanced poorly cohesive gastric carcinoma

This study aims to assess the size of metastatic lymph nodes (LNs) in advanced poorly cohesive gastric carcinoma (PC-GC) on pre-operative CT and to evaluate potential differences based on histological types. We included advanced gastric cancer patients who underwent surgery at Chung-Ang University Hospital from February 2018 to May 2023. Two abdominal radiologists, in consensus, reviewed abdominal CT scans to evaluate the presence of gastric cancer and the largest size of visible LNs at each gastric LN station on CT scans. Measurable LNs were correlated with the full pathology report from electronic database records to determine the metastatic status. We used the independent t-test to evaluate the size difference of metastatic LNs across different histologic types. We evaluated a total of 136 patients (mean age, 67.25 ± 11.97; 91 males) with advanced gastric cancers. Among them, PC-GC was found in 26 patients (19.1%). Out of 427 measurable LNs, 216 were identified as malignant based on the pathology report. metastatic LNs in PC-GC were significantly smaller than metastatic LNs in other types of gastric cancer (p < 0.001, mean ± standard deviation, 6.226 ± 2.538 mm vs. 8.825 ± 5.598 mm). The best cut-off size of the metastatic LNs was 6 mm in PC-GC, as compared with 8 mm in other types of gastric cancers. The size of metastatic LNs in advanced PC-GCs is significantly smaller than metastatic LNs in other types of gastric cancer. Therefore, lowering the size threshold to 6 mm could enhance pre-operative CT evaluation of metastatic LNs in PC-GC.