S. Imtiaz1, Y. Berger1, E. Gleeson1, H. S. Williams1, D. M. Durham1, D. Mahajan1, A. Buseck1, S. Tharakan1, S. Zheng1, R. Macfie1, D. Labow1, N. A. Cohen1, B. J. Golas1, U. Sarpel1, D. R. Magge1, S. P. Hiotis1 1Mount Sinai School Of Medicine, Division Of Surgical Oncology, New York, NY, USA
Introduction: Early stage gastric cancer, particularly T1 disease, is associated with high recurrence-free and overall survival rates following resection with curative intent. However, rare cases of T1 gastric cancer are associated with poor outcomes, including nodal metastasis.
Methods: Data from gastric cancer patients undergoing surgery at a single tertiary care institution between the years of 2010 and 2020 were analyzed. Patients with early stage (T1) disease were assessed in detail to identify variables associated with regional lymph node metastasis including histologic differentiation, signet ring cells, demographics, smoking history, neoadjuvant therapy, and clinical staging by endoscopic ultrasound (EUS). We used standard statistical techniques including Mann Whitney U and Chi-Squared tests.
Results: Of 426 patients undergoing surgery for gastric cancer, 34% (n= 146) were diagnosed with T1 disease on final pathology. Among 146 T1 (T1a, T1b) gastric cancers, 24 patients [(17%) T1a (n=4), T1b (n=20)] had histologically confirmed regional lymph node metastases. The age at diagnosis ranged between 19 to 91 and 54.8% were male. Prior smoking status was not associated with nodal positivity (p= 0.650). Of node positive patients (24/145), 7 patients received neoadjuvant chemotherapy because locally advanced disease was identified (on CT imaging) or patients had high grade features on endoscopic biopsy. EUS was performed on 91 patients (62%). Of these patients 12 (13.2%) were node positive on final pathology, however none (0/12) were detected on preoperative EUS. There was no association between node status on EUS and node status on final pathology (p=0.113). The sensitivity of EUS for N status was 0%, specificity was 84.4%, negative predictive value (NPV) was 82.2% and positive predictive value (PPV) was 0%. Signet ring cells were identified in 42% of node negative T1 tumors and 64% of node positive T1 tumors (p=0.063). For node positive cases on surgical pathology, 37.5% had poor differentiation, 42% had lymphovascular invasion, and regional nodal metastases were associated with increasing T stage (p=0.003).
Conclusion: T1 gastric cancer is associated with a substantial risk (17%) of regional lymph node metastasis. The findings of N+ disease on EUS was not significantly associated with N+ disease on final pathology in patients with T1 gastric cancer.
