title: Low-grade epithelial ovarian cancer: a number of distinct clinical entities?
abstract: OBJECTIVE
  The purpose of this study is to summarize the contemporary understanding of low-grade epithelial ovarian cancers.
  
  
  RESULTS
  Low-grade serous ovarian cancer is biologically distinct from high-grade serous ovarian cancer. It is associated with a high incidence of K-RAS and B-RAF mutations. Although described as indolent due to median progression-free and overall survivals of 20 and 99 months, respectively, with a median age of diagnosis of 43 years, it accounts for a significant number of patient-years lost. Retrospective studies suggest response rates of 5% for chemotherapy and 9% for antioestrogen therapy. A prospective study of the mitogen-activated protein kinase kinase inhibitor selumetinib (response rate 15%) and retrospective bevacizumab studies suggest that these may be more effective approaches.Limited retrospective clinical data and even more sparse molecular data suggest that similar distinctions may exist between low-grade endometrioid and mucinous ovarian cancers and their respective high-grade counterparts, but more research is required in order to clarify the biological differences and the implications that these have for management.
  
  
  CONCLUSIONS
  The results of phase III mitogen-activated protein kinase kinase inhibitor studies in low-grade serous ovarian cancer and further clinical and biological assessment of low-grade endometrioid and mucinous ovarian cancers are urgently required.
authors.affiliation: University of Edinburgh Cancer Research UK Centre, MRC IGMM, Edinburgh, UK.
authors.forename: Ailsa J
authors.initials: AJ
authors.lastname: Oswald
authors.forename: Charlie
authors.initials: C
authors.lastname: Gourley
mesh_terms: D018262:Adenocarcinoma, Clear Cell; D002288:Adenocarcinoma, Mucinous; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D014408:Biomarkers, Tumor; D018269:Carcinoma, Endometrioid; D000077216:Carcinoma, Ovarian Epithelial; D018284:Cystadenocarcinoma, Serous; D005260:Female; D006801:Humans; D058990:Molecular Targeted Therapy / Q000379:methods*; D009154:Mutation / Q000235:genetics; D009367:Neoplasm Staging; D009375:Neoplasms, Glandular and Epithelial / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf; D012189:Retrospective Studies; D016159:Tumor Suppressor Protein p53
chemical_list: D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D016159:Tumor Suppressor Protein p53; D048493:Proto-Oncogene Proteins B-raf