The role of lymphoscintigraphy in rectal laparoscopicsurgery

Background: Lymphadenectomy for rectal cancer, whether by open surgery or laparoscopy, is still a controversial subject. If we consider that ∼20% of patients have nodal obturator metastases, then we must concede that extended lymphadenectomy is useless in the other 80% of patients. We set out to determine whether lymphoscintigraphy could show the lymphatic drainage from the cancer toward the obturator lymph nodes and thus help us to select the patients who would benefit by their removal. We also analyzed the possibility of applying the concept of the sentinel node to the treatment of rectal cancer. Methods: Among 42 people who underwent laparoscopy for rectal cancer 11 patients with TNM stages T2-T3N0M0 were studied by CT & MRI, rectal ultrasonography, and lymphoscintigraphy with a colloidal injection of human albumin labeled with 99m Tc at the base of the neoplasm. Afterward, the 11 patients underwent a lymphadenectomy that extended to the obturator nodes. Results: In two patients, lymphoscintigraphy showed lymphatic drainage toward the obturator nodes. In one case, there were metastases. Lymphoscintigraphy did not show lymphatic drainage toward the obturator nodes in any of the other patients, and there were no metastases among them. It was not possible to identify a sentinel node. Conclusion: Lymphoscintigraphy can be used to select patients with rectal cancer who will be helped by a lymphadenectomy extended to the obturator nodes. However, the concept of the sentinel node cannot be applied to rectal cancer.