Clinical characteristics and outcome of patients with stage III esophageal carcinoma: a single-center experience from Turkey

Comparison of two diverse populations, British Columbia, Canada, and Ardabil, Iran, indicates several variables associated with gastric and esophageal cancer survival

Background

Geographic variation and temporal trends in the epidemiology of esophageal and gastric cancers vary according to both tumor morphology and organ subsite. This study compares 1-year survival of gastric and esophageal cancers between two distinct populations: British Columbia (BC), Canada, and Ardabil, Iran.

Methods

Data for invasive primary esophageal and gastric cancer patients were obtained from the population-based cancer registries for BC and Ardabil. The relative survival rate was calculated using WHO Statistical Information System (WHOSIS) life-tables for each country. Chi-square and Fisher’s exact tests were used to compare survival differences between BC and Ardabil. T-tests, chi-square tests, and Fisher’s exact test were used to compare patient characteristics and tumor factors between the populations.

Results

The overall 1-year age-standardized relative survivals for gastric cancer were 48% and 21% in BC and Ardabil, respectively (p < 0.01). The overall 1-year age-standardized relative survival for esophageal cancer was 33% and 17% in BC and Ardabil, respectively (p < 0.05). Overall and separately for each gender, age group, tumor location, and histology, there was greater 1-year survival of the gastric cancer patients in BC compared to Ardabil. For esophageal cancer; patients under age 65, patients with tumors in the middle or upper third of esophagus, and patients with squamous cell carcinoma had significantly better survival in BC than in Ardabil.

Conclusion

Findings of this study point to differences in disease characteristics and patient factors, not solely differences in healthcare systems, as being responsible for the survival difference in these populations.

The prognostic effect of ethnicity for gastric and esophageal cancer: the population-based experience in British Columbia, Canada

Background

Gastric and esophageal cancers are among the most lethal human malignancies. Their epidemiology is geographically diverse. This study compares the survival of gastric and esophageal cancer patients among several ethnic groups including Chinese, South Asians, Iranians and Others in British Columbia (BC), Canada.

Methods

Data were obtained from the population-based BC Cancer Registry for patients diagnosed with invasive esophageal and gastric cancer between 1984 and 2006. The ethnicity of patients was estimated according to their names and categorized as Chinese, South Asian, Iranian or Other. Cox proportional hazards regression analysis was used to estimate the effect of ethnicity adjusted for patient sex and age, disease histology, tumor location, disease stage and treatment.

Results

The survival of gastric cancer patients was significantly different among ethnic groups. Chinese patients showed better survival compared to others in univariate and multivariate analysis. The survival of esophageal cancer patients was significantly different among ethnic groups when the data was analyzed by a univariate test (p = 0.029), but not in the Cox multivariate model adjusted for other patient and prognostic factors.

Conclusions

Ethnicity may represent underlying genetic factors. Such factors could influence host-tumor interactions by altering the tumor's etiology and therefore its chance of spreading. Alternatively, genetic factors may determine response to treatments. Finally, ethnicity may represent non-genetic factors that affect survival. Differences in survival by ethnicity support the importance of ethnicity as a prognostic factor, and may provide clues for the future identification of genetic or lifestyle factors that underlie these observations.

Survivin expression in esophageal cancer: correlation with p53 mutations and promoter polymorphism

Survivin is an inhibitor of apoptosis protein, which is selectively up-regulated in various cancers including esophageal cancer. The underlying mechanism of survivin overexpression in cancers is still unclear. We investigated resected tumor specimens from 100 esophageal cancer patients. Reverse transcription polymerase chain reaction was performed to evaluate survivin gene expression. Polymerase chain reaction-single strand conformation polymorphism was performed to investigate mutations of p53. We found that the survivin expression in tumors with mutant p53 is higher than that in tumors with wild type p53. Furthermore, the distribution of three polymorphisms in survivin promoter region in esophageal cancer patients was studied. The result indicated that the survivin expression was caused by a C allele in the survivin promoter polymorphism -625G/C in some degree. The methylation profile of survivin exon1 was also evaluated using bisulfite sequencing PCR. Our result indicated that survivin mRNA overexpression in cancer was not caused by its dysmethylation status. Therefore, our results suggested that the survivin expression depended on the p53 status and the C allele in the survivin promoter polymorphism -625G/C might increase the possibility of the survivin overexpression in esophageal cancer patients.