Utilidad de la ecografía en el diagnóstico de los pacientes con sospecha de neoplasias del tubo digestivo

Abstract

The Positive Predictive Value (PPV) of signs and symptoms for the diagnosis of colon and gastric cancer is low. Furthermore, many patients are referred to us to discard a digestive tract neoplasm with no symptoms suggestive of its whereabouts, in whom clinical PPV is even lower. This study evaluates the usefulness of ultrasonography as a first approach to diagnosis. Seventy-nine patients were recruited into the study (48 males with an average age of 69.3 years). Ultrasonography was performed on all patients prior to endoscopy. Parameters studied included diagnostic accuracy for colon and gastric cancer, ultrasonographic diagnoses, and number of endoscopies that can be avoided. Predictive factors for neoplasm location were also studied. Five gastric cancers (6.3%), 12 colon cancers (15,1%), 3 pancreatic cancers (3.8%), 2 uterine neoplasms (2.5%), and 2 hypernephromas (2.5%) were diagnosed. The figures for sensitivity, specificity, PPV, Negative Predictive Value (NPV) and global accuracy of ultrasonography were 80%, 98.6%, 80%, 98.6%, and 97.4%, respectively, for gastric cancer, while these figures were 100%, 94.5%, 80%, 100%, and 95.5%, respectively, for colon cancer. Ultrasonography enabled to avoid 10% of endoscopic explorations. The only parameter that helps locate a neoplasm is the presence of anemia, which is more frequently associated with a diagnosis of colon cancer: 30.4 versus 4.3% (p = 0.033). In patients without specific symptoms who were sent to us for discarding digestive tract neoplasm, "extra-digestive" neoplasms were frequently diagnosed. If we further take into account the high diagnostic accuracy of ultrasonography, then this procedure could be a very good first approach towards such diagnosis.