**3. Is histopathological type important?**

Over the last decade, the understanding of the pathogenesis of epithelial ovarian cancer has changed. The most common histopathological subtype, high-grade serous cancer (approximately 70–80% of cases) appears to arise in the distal fallopian tube [4]. Most of these women present with disease spread to the transperitoneal surfaces and to the lymph system. The majority of this chapter will be concerned with the role of lymphadenectomy in this group of women.

Less common types of ovarian cancer include endometrioid, clear cell, low grade serous and mucinous tumours. These appear to have separate aetiologies with a different risk of lymphatic spread. The risk of nodal metastases appears to be lower in endometrioid and mucinous cancers. For example, a meta-analysis of 278 women with apparent early mucinous cancer of the ovary who underwent a full pelvic and para aortic nodal dissection reported an incidence of involved nodes of only 1.2% [5]. Most authors no longer recommend a lymphadenectomy in early mucinous cancers.
