RESUMEN
Endoscopy with biopsy sampling is the gold standard used in gastric cancer diagnosis. However, the positive predictive value of signs and symptoms for the diagnosis of carcinomas is quite limited, and, therefore, many patients are subjected to non-diagnostic endoscopies, especially when symptoms are not so specific. This study shows that ultrasonography is sensitive enough for the diagnosis of gastric cancer, and, therefore, use of this technique would further ensure a better selection of patients for endoscopy. The study included 143 patients (86 men and 57 women, with an average age of 68.6 years) who were suspected of having gastric cancer. The diagnostic accuracy of ultrasonography was evaluated in a blind study. The conventional technique was used in all cases. Demographic parameters and a series of other clinical-analytical variables were studied to look for possible gastric cancer predictive factors, which when present would make ultrasonographic results irrelevant. Statistical analysis was done using SPSS 12.0, wherein a value of P < 0.05 was considered to be statistically significant. Of the 143 patients studied, 40 were diagnosed to have gastric cancer. Sonography was able to diagnose 37 cases correctly, while there were three false negative findings and eight false positive findings. This results in 92.5% sensitivity, 92.2% specificity, 82.2% positive predictive value, 96.9% negative predictive value, and a global accuracy of 92.3%. Univariate analysis showed that persistent vomiting (P = 0.021), hemoglobin level of less than 8 g/dl (P = 0.045) and a positive ultrasonography result (P < 0.0001) were associated with a higher frequency of gastric cancer. Multivariate analysis showed that persistent vomiting, with an odds ratio for gastric cancer of 3.68 (95% confidence interval 1.15-11.79; P = 0.039), and a positive ultrasonography result, with an odds ratio for gastric cancer of 117.78 (95% confidence interval 32.45-427.49; P < 0.0001), could be considered as independent predictive factors for gastric cancer. It was concluded that ultrasonography is a very sensitive and specific technique for diagnosing gastric cancer. Gastric cancer was found to be present in just 28% of the patients studied, and their condition was suspect because of the clinical manifestations. Only vomiting and a positive ultrasonography result can be considered as independent predictive factors of gastric cancer.
