Gastric cancer in Asia: progress and controversies in surgical management

Asian Americans have better outcomes of non-metastatic gastric cancer compared to other United States racial groups: A secondary analysis from a randomized study

BACKGROUND

It has been recognized for a long time that gastric cancer behavior and outcomes might be different between patients living in Asian countries vs patients living in Western countries. It is not clear if these differences would persist between patients of Asian ancestry and patients of other racial subgroups within the multiethnic communities of North America. The current study hypothesizes that these differences will present within North American multiethnic communities.

AIM

To evaluate the impact of race on survival outcomes of non-metastatic gastric cancer patients in the United States.

METHODS

This is a secondary analysis of a randomized controlled trial (CALGB 80101 study) that evaluated two adjuvant chemoradiotherapy schedules following resection of non-metastatic gastric cancer. Kaplan-Meier analysis and log-rank testing were utilized to explore the overall and disease-free survival differences according to the race of the patients. Univariate and multivariate Cox regression analyses were then used to explore factors affecting overall and disease-free survivals.

RESULTS

A total of 546 patients were included in the current analysis. Of which, 73.8% have white race (vs 12.8% black Americans and 8.2% Asian Americans). Using Kaplan-Meier analysis/log-rank testing, Asian Americans appear to have better overall and disease-free survival outcomes compared to other United States racial groups (White Americans, Black Americans, and other racial groups) (P = 0.011; P = 0.010; respectively). Moreover, in an adjusted multivariate model, Asian American race seems to be associated with better overall and disease-free survival (hazard ratio: 0.438; 95% confidence interval: 0.254-0.754), P = 0.003; hazard ratio: 0.460; 95% confidence interval: 0.280-0.755, P = 0.002; respectively).

CONCLUSION

Asian American patients with non-metastatic gastric cancer have better overall and disease-free survival compared to other racial groups in the United States. Further preclinical and clinical research is needed to clarify the reasons behind this observation.

Protein-bound polysaccharide K induced apoptosis of the human Burkitt lymphoma cell line, Namalwa

Protein-bound polysaccharide K (PSK), which is derived from mushrooms belonging to the Basidiomycetes genus, has been clinically used as a biological response modifier (BRM) for the treatment of epithelial cancer patients in Japan and other Asian countries. There are a large number of studies on the biological activities of PSK as regards the activation of immunocompetent cells and the potential cytotoxic effects on epithelial cancer cells. However, only a few studies have been conducted to see the direct cytotoxic effects of PSK on hematological malignant cells. In this study, we investigated whether or not PSK was able to induce cellular apoptosis in hematological malignant cells. PSK was found to inhibit cell growth, and induced subsequent cellular apoptosis in the Burkkit lymphoma cell line (Namalwa), out of 33 hematological malignant cell lines tested. This PSK-induced apoptosis was neutralized by the addition of galactose to the culture medium, whereas apoptosis was augmented by treatment with beta-galactosidase, indicating the inhibitory involvement of galactose in the mechanism of action. These results provide initial evidence of the direct cytotoxic activity of PSK in a hematological malignant cell line, thus encouraging further molecular-level study of PSK-mediated apoptosis in malignant hematological cells.