The effect of progestin therapy in advanced and recurrent endometrial cancer: A systematic review and meta-analysis.

BACKGROUND: Fifteen percent of patients with endometrial cancer (EC) have advanced stage disease or develop a recurrence. Progestins have been applied as systemic treatment for decades, but there is limited evidence on response prediction with biomarkers and toxicity. OBJECTIVES: To review the response and toxicity of progestin therapy and stratify response to progesterone receptor (PR) expression and tumour grade. SEARCH STRATEGY: We used the search terms 'Endometrial cancer', 'Progestins', 'Disease progression', 'Recurrence' and related terms in Pubmed, Embase and Cochrane databases. SELECTION CRITERIA: Studies on patients with advanced stage or recurrent EC treated with progestin monotherapy were included. Studies on adjuvant therapy, with fewer than ten cases and with sarcoma histology were excluded. DATA COLLECTION AND ANALYSIS: Evaluation for bias was performed with the Revised Cochrane RoB2 tool for randomised studies and the ROBINS-I tool for non-randomised studies. A random effects meta-analysis was performed with the overall response rate (ORR), clinical benefit rate and toxicity as primary outcome measures. MAIN RESULTS: Twenty-six studies (1639 patients) were included. The ORR of progestin therapy was 30% (95% CI 25-36), the clinical benefit rate was 52% (95% CI 42-61). In PR-positive EC, the ORR was 55%, compared with 12% in PR-negative disease (risk difference 43%, 95% CI 15-71). Severe toxicity occurred in 6.5%. CONCLUSIONS: Progestin therapy is a viable treatment option in patients with advanced stage and recurrent EC with low toxicity and high ORR in PR-positive disease. The role of PR expression in relation to progression-free survival and overall survival is unclear.

Impact of hormonal biomarkers on response to hormonal therapy in advanced and recurrent endometrial cancer.

BACKGROUND: Approximately 20% of women with endometrial cancer have advanced-stage disease or suffer from a recurrence. For these women, prognosis is poor, and palliative treatment options include hormonal therapy and chemotherapy. Lack of predictive biomarkers and suboptimal use of existing markers for response to hormonal therapy have resulted in overall limited efficacy. OBJECTIVE: This study aimed to improve the efficacy of hormonal therapy by relating immunohistochemical expression of estrogen and progesterone receptors and estrogen receptor pathway activity scores to response to hormonal therapy. STUDY DESIGN: Patients with advanced or recurrent endometrial cancer and available biopsies taken before the start of hormonal therapy were identified in 16 centers within the European Network for Individualized Treatment in Endometrial Cancer and the Dutch Gynecologic Oncology Group. Tumor tissue was analyzed for estrogen and progesterone receptor expressions and estrogen receptor pathway activity using a quantitative polymerase chain reaction-based messenger RNA model to measure the activity of estrogen receptor-related target genes in tumor RNA. The primary endpoint was response rate defined as complete and partial response using the Response Evaluation Criteria in Solid Tumors. The secondary endpoints were clinical benefit rate and progression-free survival. RESULTS: Pretreatment biopsies with sufficient endometrial cancer tissue and complete response evaluation were available in 81 of 105 eligible cases. Here, 22 of 81 patients (27.2%) with a response had estrogen and progesterone receptor expressions of >50%, resulting in a response rate of 32.3% (95% confidence interval, 20.9-43.7) for an estrogen receptor expression of >50% and 50.0% (95% confidence interval, 35.2-64.8) for a progesterone receptor expression of >50%. Clinical benefit rate was 56.9% for an estrogen receptor expression of >50% (95% confidence interval, 44.9-68.9) and 75.0% (95% confidence interval, 62.2-87.8) for a progesterone receptor expression of >50%. The application of the estrogen receptor pathway test to cases with a progesterone receptor expression of >50% resulted in a response rate of 57.6% (95% confidence interval, 42.1-73.1). After 2 years of follow-up, 34.3% of cases (95% confidence interval, 20-48) with a progesterone receptor expression of >50% and 35.8% of cases (95% confidence interval, 20-52) with an estrogen receptor pathway activity score of >15 had not progressed. CONCLUSION: The prediction of response to hormonal treatment in endometrial cancer improves substantially with a 50% cutoff level for progesterone receptor immunohistochemical expression and by applying a sequential test algorithm using progesterone receptor immunohistochemical expression and estrogen receptor pathway activity scores. However, results need to be validated in the prospective Prediction of Response to Hormonal Therapy in Advanced and Recurrent Endometrial Cancer (PROMOTE) study.

Trends over time in the incidence and use of hormonal therapy in endometrial cancer: a population-based study in the Netherlands.

INTRODUCTION: According to current guidelines, hormonal therapy may be applied in endometrioid type endometrial cancer as an alternative to surgery for fertility preservation and in medically unfit patients. Since it is unknown how often hormonal therapy is applied, the objective of this study was to investigate trends over time in hormonal therapy use in the background of the overall incidence of endometrial cancer. METHODS: All patients with endometrial cancer (n=48 222) registered in the Netherlands Cancer Registry in the period 1989-2018 were included. European age-standardized incidence rates with corresponding estimated annual percentage change were calculated to describe trends in the incidence of endometrial cancer. The use of hormonal therapy was analyzed in the three periods 1989-1998, 1999-2008, and 2009-2018 for the following sub-groups: primary and adjuvant therapy, International Federation of Gynecology and Oncology (FIGO) stage I-II and III-IV, and by age group. RESULTS: The European age-standardized incidence rate of endometrioid endometrial cancer peaked in 2004 with a significant increase from 1989 to 2004 (annual percentage change 0.55; 95% CI 0.10 to 0.99, p=0.020) and a subsequent decrease from 2005 to 2018 (annual percentage change -1.79; 95% CI -2.28 to -1.31, p<0.001). The incidence rate of non-endometrioid type endometrial cancer increased significantly in the study period. Hormonal therapy was used in 1482 (3.5%) patients with endometrioid endometrial cancer. Among patients with FIGO stage I aged ≤40 years, hormonal therapy increased from 0% in 1989-1998 to 27% in 2009-2018. Primary hormonal treatment increased from 175 patients (5.5%) to 329 patients (7.8%) in those aged ≥75 years. Adjuvant hormonal treatment was mostly used in advanced stage endometrial cancer. CONCLUSIONS: The use of primary hormonal therapy in endometrioid type endometrial cancer increased over time in patients aged ≤40 years and among elderly patients. The observed trends in the current use of hormonal therapy support the need to study the effect of hormonal treatment in elderly patients and as adjuvant treatment in advanced stage endometrial cancer.

Oestrogen receptor pathway activity is associated with outcome in endometrial cancer.

BACKGROUND: Oestrogen receptor (ER) expression is a prognostic biomarker in endometrial cancer (EC). However, expression does not provide information about the functional activity of the ER pathway. We evaluated a model to quantify ER pathway activity in EC, and determined the prognostic relevance of ER pathway activity. METHODS: ER pathway activity was measured in two publicly available datasets with endometrial and EC tissue, and one clinical cohort with 107 samples from proliferative and hyperplastic endometrium and endometrioid-type EC (EEC) and uterine serous cancer (USC). ER pathway activity scores were inferred from ER target gene mRNA levels from Affymetrix microarray data (public datasets), or measured by qPCR on formalin-fixed paraffin-embedded samples (clinical cohort) and related to ER expression and outcome. RESULTS: ER pathway activity scores differed significantly throughout the menstrual cycle supporting the validity of the pathway test. The highest ER pathway scores were found in proliferative and hyperplastic endometrium and stage I EEC, whereas stage II-IV EEC and USCs had significantly lower levels. Low ER pathway activity was associated with recurrent disease, and added prognostic value in patients with low ER expression. CONCLUSION: The ER pathway test reflects activity of the ER pathway, and may improve prediction of outcome in EC patients.

Poor outcome in hypoxic endometrial carcinoma is related to vascular density.

BACKGROUND: Identification of endometrial carcinoma (EC) patients at high risk of recurrence is lacking. In this study, the prognostic role of hypoxia and angiogenesis was investigated in EC patients. METHODS: Tumour slides from EC patients were stained by immunofluorescence for carbonic anhydrase IX (CAIX) as hypoxic marker and CD34 for assessment of microvessel density (MVD). CAIX expression was determined in epithelial tumour cells, with a cut-off of 1%. MVD was assessed according to the Weidner method. Correlations with disease-specific survival (DSS), disease-free survival (DFS) and distant disease-free survival (DDFS) were calculated using Kaplan-Meier curves and Cox regression analysis. RESULTS: Sixty-three (16.4%) of 385 ECs showed positive CAIX expression with high vascular density. These ECs had a reduced DSS compared to tumours with either hypoxia or high vascular density (log-rank p = 0.002). Multivariable analysis showed that hypoxic tumours with high vascular density had a reduced DSS (hazard ratio [HR] 3.71, p = 0.002), DDFS (HR 2.68, p = 0.009) and a trend for reduced DFS (HR 1.87, p = 0.054). CONCLUSIONS: This study has shown that adverse outcome in hypoxic ECs is seen in the presence of high vascular density, suggesting an important role of angiogenesis in the metastatic process of hypoxic EC. Differential adjuvant treatment might be indicated for these patients.

Impact of body mass index and fat distribution on sex steroid levels in endometrial carcinoma: a retrospective study.

BACKGROUND: Obesity is an important cause of multiple cancer types, amongst which endometrial cancer (EC). The relation between obesity and cancer is complicated and involves alterations in insulin metabolism, response to inflammation and alterations in estradiol metabolism. Visceral obesity is assumed to play the most important role in the first two mechanisms, but its role in estradiol metabolism is unclear. Therefore, this retrospective study explores the relationship of body mass index (BMI), visceral fat volume (VAV) and subcutaneous fat volume (SAV) and serum levels of sex steroids and lipids in patients with endometrial cancer. METHODS: Thirty-nine postmenopausal EC patients with available BMI, blood serum and Computed Tomography (CT) scans were included. Serum was analyzed for estradiol, dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, cholesterol, triglycerides and high (HDL), low (LDL) and non-high density (NHDL) lipoprotein. VAV and SAV were quantified on abdominal CT scan images. Findings were interpreted using pearson correlation coefficient and linear regression with commonality analysis. RESULTS: Serum estradiol is moderately correlated with BMI (r = 0.62) and VAV (r = 0.58) and strongly correlated with SAV (r = 0.74) (p < 0.001 for all). SAV contributes more to estradiol levels than VAV (10.3% for SAV, 1.4% for VAV, 35.9% for SAV and VAV, p = 0.01). Other sex steroids and lipids have weak and moderate correlations with VAV or SAV. CONCLUSIONS: This study shows that serum estradiol is correlated with BMI and other fat-distribution measures in postmenopausal endometrial cancer patients. Subcutaneous fat tissue contributes more to the estradiol levels indicating that subcutaneous fat might be relevant in endometrial cancer carcinogenesis.

Fucoidan Structure and Activity in Relation to Anti-Cancer Mechanisms.

Fucoidan is a natural derived compound found in different species of brown algae and in some animals, that has gained attention for its anticancer properties. However, the exact mechanism of action is currently unknown. Therefore, this review will address fucoidans structure, the bioavailability, and all known different pathways affected by fucoidan, in order to formulate fucoidans structure and activity in relation to its anti-cancer mechanisms. The general bioactivity of fucoidan is difficult to establish due to factors like species-related structural diversity, growth conditions, and the extraction method. The main pathways influenced by fucoidan are the PI3K/AKT, the MAPK pathway, and the caspase pathway. PTEN seems to be important in the fucoidan-mediated effect on the AKT pathway. Furthermore, the interaction with VEGF, BMP, TGF-ß, and estrogen receptors are discussed. Also, fucoidan as an adjunct seems to have beneficial effects, for both the enhanced effectiveness of chemotherapy and reduced toxicity in healthy cells. In conclusion, the multipotent character of fucoidan is promising in future anti-cancer treatment. However, there is a need for more specified studies of the structure⁻activity relationship of fucoidan from the most promising seaweed species.

The effect of carbogen breathing and nicotinamide added to standard (chemo)radiation treatment of advanced cervical cancer in Indonesia.

OBJECTIVE: Chemoradiation is the standard therapy for advanced stages of cervical cancer. In developing countries, where 80% of cervical cancers occur, this is not always available. Carbogen breathing and oral nicotinamide (CON) therapy, aimed at overcoming tumor hypoxia, has shown to improve treatment efficacy in some epithelial tumors. This study investigates the effect of CON during (chemo)radiation of advanced stages of cervical cancer on overall survival, local and regional control, and toxicity. METHODS: From December 2006 to February 2010, 139 patients with stage IB2 to IVA cervical cancer were nonrandomly assigned to receive radiotherapy (RT) or chemoradiation (CRT) with or without CON. Differences in overall survival, local and regional control after 1 year, and toxicity were assessed in 113 evaluable patients. Thirty-two patients received RT, 16 received CRT, 45 received CON-RT, and 20 received CON-CRT. RESULTS: The CON-RT and RT groups contained significantly more patients with a poor performance status and IIIB and IVA tumors. Despite these differences in baseline characteristics, overall survival and local and regional control at 1 year were not significantly different (P = 0.10 and P = 0.19, respectively). Toxicity scores also did not differ (P = 0.60 and P = 0.73 for acute and late toxicity). CONCLUSIONS: Addition of CON to standard (chemo)radiation gives comparable survival and control rates. The effect of CON might be underestimated due to differences in baseline characteristics. Because chemotherapy cannot always be (completely) administered in low-resource settings, CON could be a worthy substitute. The CON treatment is feasible and safe.

Hormone Receptor Expression and Activity for Different Tumour Locations in Patients with Advanced and Recurrent Endometrial Carcinoma.

BACKGROUND: Response to hormonal therapy in advanced and recurrent endometrial cancer (EC) can be predicted by oestrogen and progesterone receptor immunohistochemical (ER/PR-IHC) expression, with response rates of 60% in PR-IHC > 50% cases. ER/PR-IHC can vary by tumour location and is frequently lost with tumour progression. Therefore, we explored the relationship between ER/PR-IHC expression and tumour location in EC. METHODS: Pre-treatment tumour biopsies from 6 different sites of 80 cases treated with hormonal therapy were analysed for ER/PR-IHC expression and classified into categories 0-10%, 10-50%, and >50%. The ER pathway activity score (ERPAS) was determined based on mRNA levels of ER-related target genes, reflecting the actual activity of the ER receptor. RESULTS: There was a trend towards lower PR-IHC (33% had PR > 50%) and ERPAS (27% had ERPAS > 15) in lymphogenic metastases compared to other locations (p = 0.074). Hematogenous and intra-abdominal metastases appeared to have high ER/PR-IHC and ERPAS (85% and 89% ER-IHC > 50%; 64% and 78% PR-IHC > 50%; 60% and 71% ERPAS > 15, not significant). Tumour grade and previous radiotherapy did not affect ER/PR-IHC or ERPAS. CONCLUSIONS: A trend towards lower PR-IHC and ERPAS was observed in lymphogenic sites. Verification in larger cohorts is needed to confirm these findings, which may have implications for the use of hormonal therapy in the future.

Robot-Assisted Total Laparoscopic Hysterectomy in Different Classes of Obesity: A Cohort Study.

Background and Objectives: Robot-assisted laparoscopic hysterectomy is a safe and feasible approach in patients with higher body mass index (BMI). Slightly longer operating time in patients with high BMI did not result in higher complication or conversion rates. The purpose of this study was to evaluate whether robot-assisted total laparoscopic hysterectomy is a feasible and safe surgical approach in different classes of obesity. Methods: A single center retrospective cohort study was performed in a large secondary teaching hospital in the Netherlands. All patients who underwent robot-assisted total laparoscopic hysterectomy between January 1, 2011 and January 31, 2019 were included. Results: Data regarding patient characteristics, complication rate, conversion rate, skin-to-skin time, robot console time, and operating room time were collected. Surgery specific data were compared in patients with several classes of obesity. In total 356 cases were included. Median BMI was 29 kg/m2 (range 18 - 59). Complication rate and conversion to laparotomy did not differ significantly in different classes of obesity. Robot console time and skin-to-skin time was significantly longer in women with a BMI ≥ 40 kg/m2 (n = 34) compared to patients with normal BMI. Conclusion: Robot-assisted laparoscopic hysterectomy is a safe and feasible approach in women in different classes of obesity. The significantly prolonged operating time does not result in higher complication or conversion rates.

Relevance of Molecular Profiling in Patients With Low-Grade Endometrial Cancer.

Importance: Patients with low-grade (ie, grade 1-2) endometrial cancer (EC) are characterized by their favorable prognosis compared with patients with high-grade (ie, grade 3) EC. With the implementation of molecular profiling, the prognostic relevance of tumor grading might lose attention. As most patients present with low-grade EC and have an excellent outcome, the value of molecular profiling for these patients is unclear. Objective: To determine the association of molecular profiling with outcomes among patients with low-grade EC. Design, Setting, and Participants: This retrospective cohort study included a multicenter international European cohort of patients diagnosed with EC between 1994 and 2018, with a median follow-up of 5.9 years. Molecular subgroups were determined by next-generation sequencing using single-molecule molecular inversion probes and by immunohistochemistry. Subsequently, tumors were classified as polymerase epsilon (POLE)-altered, microsatellite instable (MSI), tumor protein p53 (TP53)-altered, or no specific molecular profile (NSMP). Patients diagnosed with any histological subtypes and FIGO (International Federation of Gynecology and Obstetrics) stages of EC were included, but patients with early-stage EC (FIGO I-II) were only included if they had known lymph node status. Data were analyzed February 20 to June 16, 2022. Exposures: Molecular testing of the 4 molecular subgroups. Main Outcomes and Measures: The main outcome was disease-specific survival (DSS) within the molecular subgroups. Results: A total of 393 patients with EC were included, with a median (range) age of 64.0 (31.0-86.0) years and median (range) body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 29.1 (18.0-58.3). Most patients presented with early-stage (290 patients [73.8%]) and low-grade (209 patients [53.2%]) disease. Of all patients, 33 (8.4%) had POLE-altered EC, 78 (19.8%) had MSI EC, 72 (18.3%) had TP53-altered EC, and 210 (53.4%) had NSMP EC. Across all molecular subgroups, patients with low-grade EC had superior 5-year DSS compared with those with high-grade EC, varying between 90% to 100% vs 41% to 90% (P < .001). Multivariable analysis in the entire cohort including age, tumor grade, FIGO stage, lymphovascular space invasion, and the molecular subgroups as covariates found that only high-grade (hazard ratio [HR], 4.29; 95% CI, 2.15-8.53; P < .001), TP53-altered (HR, 1.76; 95% CI, 1.04-2.95; P = .03), and FIGO stage III or IV (HR, 4.26; 95% CI, 2.50-7.26; P < .001) disease were independently associated with reduced DSS. Conclusions and Relevance: This cohort study found that patients with low-grade EC had an excellent prognosis independent of molecular subgroup. These findings do not support routine molecular profiling in patients with low-grade EC, and they demonstrate the importance of primary diagnostic tumor grading and selective profiling in low-grade EC to increase cost-effectiveness.

[Fertility sparing treatment of endometrial carcinoma]. / Fertiliteitsparende behandeling endometriumcarcinoom.

BACKGROUND: The incidence of endometrial carcinoma (EC) is rising worldwide due to an increased life expectancy and obesity. Approximately 2% of patients with EC is under the age of 45. Because the incidence is also rising in young women, there is a clinical need for safe fertility sparing alternative treatments. CASE DESCRIPTION: A 32-year-old women was diagnosed with low-grade endometrioid EC. Hysteroscopic tumour resection and progestin treatment resulted in complete tumour regression. The patient became pregnant through in vitro fertilisation (IVF). CONCLUSION: This case illustrates that fertility sparing treatment, with oral progestin treatment is an alternative treatment option in selected young women with low grade, early stage endometrial carcinoma to achieve pregnancy. This treatment is internationally accepted.

Recurrent Endometrial Cancer: Local and Systemic Treatment Options.

The treatment of recurrent endometrial cancer is a challenge. Because of earlier treatments and the site of locoregional recurrence, in the vaginal vault or pelvis, morbidity can be high. A total of about 4 to 20% of the patients with endometrial cancer develop a locoregional recurrence, mostly among patients with locally advanced disease. The treatment options are dependent on previous treatments and the site of recurrence. Local and locoregional recurrences can be treated curatively with surgery or (chemo)radiotherapy with acceptable toxicity and control rates. Distant recurrences can be treated with palliative systemic therapy, i.e., first-line chemotherapy or hormonal therapy. Based on the tumor characteristics and molecular profile, there can be a role for immunotherapy. The evidence on targeted therapy is limited, with no approved treatment in the current guidelines. In selected cases, there might be an indication for local treatment in oligometastatic disease. Because of the novel techniques in radiotherapy, disease control can often be achieved at limited toxicity. Further studies are warranted to analyze the survival outcome and toxicity of newer treatment strategies. Patient selection is very important in deciding which treatment is of most benefit, and better prediction models based on the patient- and tumor characteristics are necessary.

The cutoff for estrogen and progesterone receptor expression in endometrial cancer revisited: a European Network for Individualized Treatment of Endometrial Cancer collaboration study.

There is no consensus on the cutoff for positivity of estrogen receptor (ER) and progesterone receptor (PR) in endometrial cancer (EC). Therefore, we determined the cutoff value for ER and PR expression with the strongest prognostic impact on the outcome. Immunohistochemical expression of ER and PR was scored as a percentage of positive EC cell nuclei. Cutoff values were related to disease-specific survival (DSS) and disease-free survival (DFS) using sensitivity, specificity, and multivariable regression analysis. The results were validated in an independent cohort. The study cohort (n = 527) included 82% of grade 1-2 and 18% of grade 3 EC. Specificity for DSS and DFS was highest for the cutoff values of 1-30%. Sensitivity was highest for the cutoff values of 80-90%. ER and PR expression were independent markers for DSS at cutoff values of 10% and 80%. Consequently, three subgroups with distinct clinical outcomes were identified: 0-10% of ER/PR expression with, unfavorable outcome (5-year DSS = 75.9-83.3%); 20-80% of ER/PR expression with, intermediate outcome (5-year DSS = 93.0-93.9%); and 90-100% of ER/PR expression with, favorable outcome (5-year DSS = 97.8-100%). The association between ER/PR subgroups and outcomes was confirmed in the validation cohort (n = 265). We propose classification of ER and PR expression based on a high-risk (0-10%), intermediate-risk (20-80%), and low-risk (90-100%) group.

Impact of different adjuvant treatment approaches on survival in stage III endometrial cancer: A population-based study.

BACKGROUND: Patients with International Federation of Gynaecology and Obstetrics (FIGO) stage III endometrial cancer (EC) have a substantial risk of adverse outcomes. After surgery, adjuvant therapy is recommended with external beam radiotherapy (EBRT), chemotherapy (CT) or both EBRT and CT. Recent trials suggest that EBRT + CT is superior to EBRT or CT alone but also results in more toxicity. We have compared the outcome of different adjuvant treatments in a population-based cohort to identify subgroups that benefit most from EBRT + CT. METHODS: All patients diagnosed with FIGO stage III EC and treated with surgery in 2005-2016 were identified from the Netherlands Cancer Registry. The primary outcome was overall survival (OS); associations with adjuvant treatment were analysed using Cox regression analysis. RESULTS: Among 1241 eligible patients, EBRT + CT was associated with a better OS than CT (hazard ratio [HR] = 1.84, 95% confidence interval [CI] = 1.34-2.52) and EBRT alone (HR = 1.37, 95% CI = 1.05-1.79). In stage IIIC, there was a significant benefit of EBRT + CT compared with CT or EBRT alone. In stage IIIA-B, there was no difference between EBRT + CT or EBRT alone. In endometrioid EC (EEC) and carcinosarcomas, EBRT + CT was associated with a better OS than CT or EBRT alone. For uterine serous cancers, there was no survival benefit of EBRT + CT over CT. In all analysis by stage and histology, any adjuvant treatment was superior to no adjuvant therapy. CONCLUSIONS: In this population-based study, adjuvant EBRT + CT was associated with improved OS compared with CT or EBRT alone in FIGO stage IIIC EC, EEC and carcinosarcoma. This suggests that application of EBRT + CT in stage III should be further stratified according to these subgroups.

Anti-estrogen Treatment in Endometrial Cancer: A Systematic Review.

Introduction: Hormonal therapy in endometrial cancer (EC) is used for patients who wish to preserve fertility and for patients with advanced or recurrent disease in a palliative setting. First line hormonal therapy consists of treatment with progestins, which has a response rate of 25% in an unselected population. Treatment with anti-estrogens is an alternative hormonal therapy option, but there is limited data on the effect and side-effects of anti-estrogens in EC. Therefore, we performed a systematic review to investigate the response rate and toxicity of anti-estrogenic therapy in patients with endometrial cancer. Methods: A systematic search in electronic databases was performed to identify studies on selective estrogen receptor modulators (SERM) and down-regulators (SERD) and aromatase inhibitors that reported on response rates (RR) among EC patients. Outcome in estrogen receptor (ER) positive and negative disease was assessed independently. Results: Sixteen studies on advanced stage and recurrent EC were included. Ten studies investigated anti-estrogen monotherapy and seven investigated a combination of anti-estrogenic drugs with either progestin or targeted treatment. Due to heterogeneity in patient population, no meta-analysis was performed. The median age of the patients in the included studies ranged from 61 to 71 years and the proportion of low grade tumors ranged from 38 to 80%. The RR for tamoxifen ranged from 10 to 53%, for other SERMs and SERDs 9-31%, for aromatase inhibitors from 8 to 9%, for combined tamoxifen/progestin treatment 19-58%, for combined chemo- and hormonal therapy 43% and for combination of anti-estrogenic treatment with mammalian target of rapamycin (mTOR) inhibitors 14-31%. Toxicity consisted mainly of nausea and thrombotic events and was higher in combination therapy of chemotherapy and hormonal therapy and hormonal therapy and mTOR inhibitors compared to other therapies. Conclusion: Tamoxifen or a combination of tamoxifen and progestin should be the preferred choice when selecting second line hormonal treatment because the RRs are similar to first line progestin treatment and the toxicity is low. The response can be optimized by selecting patients with endometrioid tumors and positive estrogen receptor status, which should be based on a pretreatment biopsy.