Background: Gastric cancer, with notable regional variations in incidence rates, ranks as the third most prevalent cause of cancer-related deaths globally and the fifth most common cancer overall. The objective of this research is to examine the pathological, clinical, and demographic features of patients diagnosed with undifferentiated gastric cancer (UGC) and to determine the major prognostic markers that impact survival and recurrence.

Materials and Methods: This retrospective analysis included patients who underwent gastric cancer surgery at our center between March 2010 and February 2019. Inclusion criteria confirmed diagnosis of UGC and pathological data. Data collected included demographic information, clinical parameters, pathological findings, surgical details, and survival data. The primary outcomes were overall survival and local recurrence.

Results: Twenty-four patients were included, of whom 66.7% were male, with a mean age of 58.5 years. Local recurrence occurred in 50% of patients, significantly associated with perineural and vascular invasion. ROC analysis identified a metastatic lymph node cutoff of 8.5 with an AUC of 0.826, specificity of 100%, and sensitivity of 63.2%. Patients with fewer than 8.5 metastatic lymph nodes had a median survival of 16.0 months versus 7.0 months for those with more (p = 0.003).

Conclusion: Perineural and vascular invasion significantly impact local recurrence in UGC patients. A metastatic lymph node cutoff of 8.5 is a critical predictor of mortality. These findings emphasize the importance of thorough pathological assessments and nodal evaluations to guide treatment decisions and improve outcomes. Further research is needed to validate these results and explore additional prognostic markers.