Endometrial cancer: A systematic review of HE4, REM and REM-B

Introduction: Endometrial cancer, one of the most frequent pelvic gynecologic cancer worldwide, currently has no biomarker used to assess it in daily practice. Nonetheless, human epididymis 4 (HE4) appears to offer the best prospects, alone or combined with CA125. This study sought to systematically review the work on HE4 from the first publications in 2008 until now. Material and methods: Two independent reviewers searched the PubMed database with the terms "HE4'', "endometrial cancer", "endometrial carcinoma", and HE4 or human epididymis protein 4. Only original clinical research articles and meta-analyses, published in English, were included, with literature reviews and case reports excluded. Results: Studies were organized into 3 categories: diagnosis, prognosis, and recurrence/survival. Overall we identified 117 articles dealing with HE4 and endometrial cancer and selected 52 relevant texts: 46 articles, 6 meta-analyses. The sensitivity of HE4 for the diagnosis of endometrial cancer varied from 44.2% to 91% and its specificity from 65.5 to 100%, versus 24.1 to 71.5% and from 65.6 to 100% for CA125. Two meta-analyses of their combination produced areas under the curve (AUC): 0.83 and 0.86. Two available algorithms - the REM (risk of endometrial malignancy) and REM-B (risk of endometrial malignancy associated with BMI) scores - require more study. HE4 is also strongly associated with prognostic factors such as myometrial invasion, tumor grade, FIGO stage, and lymph node involvement. It also predicts recurrence and can serve as a monitoring tool, as reported by a 2018 meta-analysis with a hazard ratio of 2.15 (P < 0.001). Conclusion: HE4, alone or associated with CA125, appears to be an important tool in the management of endometrial cancer, initially for diagnosis, but for assessing prognosis and survival. Other prospective and multicenter studies are necessary to confirm these hopes and be able to recommend the use of HE4 in regular practice.