Clinical Impact of Clinicopathological Characteristics of Undifferentiated Advanced Gastric Cancer in Elderly Patients

Background: Little is known about the clinicopathological findings in elderly patients with undifferentiated advanced gastric cancer. The aim of this study was to clarify the clinical impact of clinicopathological characteristics of those cancers in elderly patients. Method: A total of 42 patients aged 80 years or older with advanced gastric cancer who had undergone curative gastrectomy between 1998 and 2015 were included in this study. All patients were classified into two principal subgroups based on histology: undifferentiated group and differentiated group. The two groups were examined and compared with respect to the pathological findings and clinical outcomes. Results: Of the 47 patients, 23 (49%) patients were in the undifferentiated group and 24 (51%) were in the differentiated group. The undifferentiated cancer was less frequently located in the upper third of the stomach than the differentiated cancer (4% vs 42%, P < 0.01). The frequency of the cancer with depth of T4a was higher in the undifferentiated group than in the differentiated group (48% vs. 17%, P < 0.05). The median number of metastatic lymph nodes in the undifferentiated group was more than that in the differentiated group (3 vs. 1, P < 0.05). In short- and long-term outcome after curative gastrectomy, there were no differences between the two groups. Conclusion: In elderly patients, undifferentiated advanced gastric cancer may have more malignant potential than differentiated cancer. However, by curative gastrectomy, the elderly patients with undifferentiated advanced gastric cancer can be obtained the equivalent clinical outcome to those with differentiated cancer.