Evaluation of lateral lymph node metastases in advanced distal rectal cancer.
The importance of lateral node dissection has not yet been fully investigated in advanced rectal cancer. To evaluate tumor cells in perirectal and lateral lymph nodes dissection from rectal adenocarcinomas considered free of disease by the hematoxylin-eosin test. Fifteen patients submitted to neoadjuvant therapy and surgery for rectal adenocarcinoma with lateral node dissection were studied, retrospectively. The paraffin blocs of the nodes were analyzed with a immunohistochemical study and multiples cross section of the nodes. A total of 331 lymph nodes from these 15 patients were assessed, distributed as 258 perirectal nodes, 73 non perirectal, and 27 lateral nodes. The average was 22.1 lymph nodes per patient. Three patients out of 15 (20%) with histological negative lateral lymph node had occult metastasis detected by pancytokeratins AE1 and AE3. One of these cases didn't present tumor in the surgical specimen of the rectum. A case of positive lateral node identified by hematoxylin-eosin was also identified by immunohistochemical study. Although we had a small number of patients in the present study, lateral node dissection is important in selected cases of advanced cancer. Pancytokeratins AE1 and AE3 had a potential to improve study for detection of occult node metastasis, being helpful in rectal cancer prognosis.