Sentinel lymph node mapping for endometrial cancer: a modern approach to surgical staging

Most patients with endometrial cancer will present with early-stage disease. Although the rate of metastasis in these patients is low, proffering excellent prognoses, the standard of treatment in many practices still includes a complete or selective pelvic and para-aortic lymphadenectomy for staging; and accurate surgical staging is the most important prognostic factor. Many patients will undergo a comprehensive lymphadenectomy despite having disease confined to the uterus, resulting in prolonged operating time, additional cost, and potential side effects, such as lower extremity lymphedema. However, recent studies show that a complete lymphadenectomy may have no therapeutic benefit in patients with early-stage endometrial cancer. Sentinel lymph node (SLN) mapping, which has been used in other cancer types, may be an acceptable surgical strategy between a complete lymphadenectomy and no nodal evaluation in patients with endometrial cancer. SLN mapping is based on the concept that lymph node metastasis is the result of an orderly process; that is, lymph drains in a specific pattern away from the tumor, and therefore, if the SLN, or first node, is negative for metastasis, then the nodes after the SLN should also be negative. This approach can help patients avoid the side effects associated with a complete lymphadenectomy, although disease must be thoroughly staged for accurate prognosis and determination of appropriate treatment approach. Surgeon experience, adherence to an SLN algorithm, and the use of pathologic "ultrastaging" are key factors for successful SLN mapping.