Mapping Sentinel Lymph Node in Initial Stages of Ovarian Cancer

Epithelial ovarian cancer (EOC) diagnosed in the initial stage (stage I-II) require complete staging surgery to histologically assess the possible existence of peritoneal or lymph node disease. Systematic pelvic and paraaortic lymphadenectomy in stage I-II EOC is essential since confirming the presence of lymph node metastases means re-staging the disease as stage III. This change of stage has important prognostic and therapeutic implications. However, the lymph node involvement rate is around 10-30% (average of 15%). Systematic pelvic and para-aortic lymphadenectomy carries a risk of intraoperative complications, as well as longer operative time, postoperative complications and longer hospital stay. Moreover, by now there is no evidence suggesting a possible therapeutic value. The sentinel lymph node (SLN) detects the first level of lymph node drainage. The absence of metastases in the SLN predicts the absence of tumor infiltration of the rest of lymph nodes of the same anatomical region and allows to safely avoid lymphadenectomy and its associated morbidity. In addition, the exhaustive evaluation of the SLN by ultrastaging and immunohistochemical study allows to increase the detection of microscopic disease. Sentinel lymph node (SLN) biopsy, implemented in clinical practice in other gynecological tumors (breast, vulva, cervix or endometrium), has been studied very little in the initial ovarian epithelial cancer. Unlike other gynecological tumors, there are multiple anatomical and technical aspects that largely explain this lack of information. The double ovarian vascularization that accompanies lymphatic drainage explains this higher complexity. Therefore, at the present time, the detection of SLN in the initial EOC remains an experimental area without applicability in clinical practice. There are multiple doubts and issues to be resolved regarding the different tracers, the site and time injection and the actual accuracy of the SLN versus the lymphadenectomy.