The value of abdominal ultrasound in the diagnosis of colon cancer

Abstract

Introduction: colon cancer is one of the main causes of cancer death. Diagnosis requires the examination of the entire large bowel by means of radiological or endoscopic techniques. Many patients suspect of colon cancer are referred for colonoscopy but nevertheless this suspicion is not confirmed after endoscopic examination. The objective of this study is the evaluation of the reliability of abdominal ultrasound in the diagnosis of these tumors.Material and method: we selected patients suspect of colon cancer referred to the endoscopy unit for a colonoscopy. An abdominal ultrasound was carried out on all patients prior to the endoscopy. Considering the endoscopic examination as a gold standard, the sensibility, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the ultrasonography were evaluated. Likewise, a series of analytical and clinical parameters were evaluated, in an attempt to establish associated factors of a colon cancer. The statistical analysis was carried out by means of the statistical package SPSS 12.0 for Windows.Results: 145 patients were included in the study (56.6% males) with an average 66.72 years of age (22-89). A cancer was diagnosed in 42 cases (28.9%). In the diagnosis of colon cancer, abdominal ultrasound presents a sensitivity of 79.06%, a specificity of 92.15%, a PPV and a NPV of 80.9% and of 91.2%, respectively. Excluding from the analysis lesions of the rectal ampulla, which cannot be adequately evaluated by means of ultrasound, the figures for sensitivity, specificity, PPV and NPV increase to 91.8, 92.1, 80.9 and 96.9% respectively. The univariate analysis showed that an age over 65 years and the presence of microcytosis are associated to a greater risk of colon cancer while after multivariate analysis only the presence of microcytosis resulted to be an independent predictive factor of cancer.Conclusions: abdominal ultrasound presents high sensitivity, specificity, PPV and NPV in the diagnosis of colon cancer. The combination of an ultrasonography and a rectoscopy permits us to rule out the presence of a colorectal carcinoma. In patients with microcytosis of 65 years and over, if there is strong clinical suspicion, a negative ultrasound may not be sufficient to rule out a colorectal neoplasia.

Role of Ultrasonography in Diagnosis of Cancers of the Gastrointestinal Tract

“…Both studies found low specificities. The most important reasons for lower accuracy ratios with US examination as compared to endoscopy include localization of colon tumors in the rectosigmoid area and the failure of abdominal US to optimally examine this area as well as failure to demonstrate small polyps and early-phase lesions by US [10]. Our study also found a low specificity and sensitivity for US, which may be affected by the small number of patients.…”

Color Doppler US and CEUS in colorectal cancer: A case report

“…Excluding evaluation of the rectal ampulla, Martínez-Ares et al achieved a sensitivity of 91.8%, specificity of 92.1%, positive predictive value of 80.9% and negative predictive value of 96.9% by considering US examination positive for malignancy when the identified mass was hypoechoic with loss of stratification and mobility of the wall. As expected, they furthermore showed that diagnosis of small polyps was not possible and that they were not resectable [5]. Like in our case, by observing the peristaltic movements, US can diagnose a substenotic or stenosis-free condition thus providing the clinician and the surgeon with information about the precise location and the cause of stenosis [6].…”

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

“…En lo que al diagnóstico del cáncer de colon se refiere, nuestras cifras (sensibilidad del 100%, una especificidad del 94,5%) están bastante por encima de las obtenidas por otros autores que también han usado la ecografía convencional (14)(15)(16)(17)(18)(19)(20) y están muy próximas a las obtenidas mediante ecografía hidrocolónica (21)(22)(23)(24)(25)(26). Ya en un estudio previo publicado recientemente por nuestro grupo (aunque en este caso se incluían pacientes en los que se sospechaba específicamente un cáncer de colon e incluíamos a 42 pacientes con cáncer de colon) se obtenían unas cifras de precisión diagnóstica similares (27).…”