Objective: the accuracy of preoperative endorectal ultrasound in the status evaluation of lymph nodes is around 50-70%, with a lack of eco-morphological patterns of clinical use. Since, accurate local staging is of great value in prognosis and decision-making we decided to analyze the referenced eco-morphological parameters in an attempt to find a proper predictive tool of clinical help that could improve the accuracy of rectal ultrasound.Material and method: the resected specimens of 24 patients that were operated on by radical surgery because rectal cancer, without preoperative radiotherapy, were suspended in warm water and ultrasound scanned (360° circular probe with a transducer of 10 MHz). All suspicious nodes were recorded and marked for the definitive histological report.Results: from the 24 specimens, 318 nodes were imaged (210 benign and 100 involved). All ultrasound parameters analyzed were significant but only lobulation, echogenicity and hilar reflection were independent values. An score system was design with the addition of all parameters that showed a sensitivity of 98% and specificity of 99,1%.Conclusions: our study shows that a careful study of ultrasound lymph node images can get a high level of accuracy and better help in tailoring the treatment of any particular case.Key words: Rectal cancer. Endorectal ultrasound. Lymph node.
INTRODUCTIONColo-rectal carcinoma is the most common malign digestive neoplasm in countries with comparable geographical and socio-economic conditions to ours. Half of these tumors are located in the rectum and the recto-sigmoid junction. Rectal cancer is understood at this time as a differentiated oncologic entity due to the peculiar characteristics of its diagnosis and treatment. In these last few years, a multi-disciplinary approach to this entity, with individualized treatment, has achieved substantial improvement in terms of local recurrence, quality of life and survival (1). In this sense, the optimal results of this treatment are directly connected to the precision with which the preoperative study is made (2).In rectal cancer, this loco-regional preoperative evaluation refers us both to the state of the primary tumor as well as to the situation of the meso-rectal lymph nodes, which are important in the prognosis of the patient and are influential in the taking of decisions (3).Although in the last few decades diagnostic imaging techniques have improved greatly -e.g. magnetic resonance (MR) or computerized tomography (CT)-, endorectal ultrasound (E-R U/S) continues to be the most effective loco-regional pre-operative evaluation for cancer of the rectum (4,5). Even though this is the case, the efficiency of evaluating lymph nodes is between 50 and 70% in most studies (6,7). Since it has great negative predictive value, these results are due mostly to the inability of E-R U/S to differentiate metastatic from inflammatory nodes. There are no generally accepted echo-morphological patterns for lymphatic invasion and those which do exist are difficult to put into pract...