Objective: The detection of sentinel nodes is performed in various types of malignant disease. The aim of this study was to evaluate the results of the radiodetection of sentinel nodes, based on the use of Tc-colloid, during the surgical treatment of rectal cancer.
Methods: In 2003-2004, 42 patients (24 males and 18 females; average ages of 62.4 and 67 years, respectively) were examined during rectal carcinoma surgical procedures. Miles abdominoperineal rectal resection was performed in nine cases; 33 patients underwent low anterior rectum resection by total mesorectal excision. On the day of the operation, a transanal submucosal infiltration of colloid labelled with radioactive 99mTc was performed; infiltration was performed strictly peritumorally. After the operation, radiodetection of the surgical specimens (using a hand-held gamma probe) was performed. The areas of higher radioactivity were marked. The specimens were then examined by a histopathologist. The nodes found closest to the marked areas were considered to be 'sentinel nodes'. The results of scintigraphy and postoperative radiodetection were checked by histological examination. All the discovered lymph nodes were examined by haematoxylin and eosin staining; when this was negative, immunohistochemical examination with cytokeratin was used for the sentinel nodes.
Results: In 36 of the 42 patients, the data obtained by scintigraphy and radiodetection were in agreement with histopathological proof of a sentinel node. The sensitivity of the method in this group of patients was 86% (95% confidence limits: 70.75-94.05).
Conclusions: The scintigraphic method of detection of sentinel nodes in total mesorectal excision is not therapeutic, but diagnostic, and demonstrates a high level of reliability. It can be used to indicate the nodes that should be examined to detect the presence of possible micrometastases immunohistochemically. However, this method cannot be used for all detected nodes as it is very demanding. In the evaluated group of patients, there were no intraoperative or postoperative complications caused by this diagnostic method.