Preoperative Serum CA 125 Level as a Predictor for Metastasis and Survival in Endometrioid Endometrial Cancer

Preoperative serum tissue factor pathway inhibitor‑2 level as a prognostic marker for endometrial cancer

Advanced endometrial cancer (EC) often recurs and has a poor prognosis. Various serum markers have been used for EC but their usefulness as biomarkers is still unclear; therefore, identifying new biomarkers is important. The present study aimed to investigate whether the tissue factor pathway inhibitor-2 (TFPI2) level was elevated in the preoperative serum of patients with EC and if it may be a prognostic factor. The present retrospective study included 207 patients who had a confirmed pathological diagnosis of EC and received surgical therapy as the initial treatment between January 2011 and December 2017. Survival analysis was performed using Kaplan-Meier analysis and the Cox proportional hazards regression model. The 5-year disease-free survival and overall survival (OS) rates were 73.3 and 83.7%, respectively. The cut-off value for predicting OS for TFPI2 level was 177 pg/ml as determined from the receiver operating characteristic curve. A TFPI2 value ≥177 pg/ml was significantly associated with age ≥65 years (P<0.001), diabetes (P=0.035), stage (P<0.001), myometrial invasion (P<0.001), lymphovascular invasion (P=0.004), lymph node metastasis (P=0.010), distant metastasis (P<0.001), cancer antigen (CA) 125 ≥36 U/ml (P<0.001) and CA 19-9 ≥38 U/ml (P<0.001). In multivariate analysis, high-grade carcinoma [hazard ratio (HR), 2.439; P=0.041], lymph node metastasis (HR, 2.116; P=0.038), distant metastasis (HR, 3.604; P=0.009) and TFPI2 level ≥177 pg/ml (HR, 2.42; P=0.043) were significant prognostic factors affecting OS in patients with EC. These results suggest that the preoperative serum TFPI2 level, along with its histological type, lymph node metastasis and distant metastasis, was a prognostic factor for OS in patients with endometrial cancer.

Preoperative serum CA125 level and age at diagnosis: An effective prognosis prediction tool for patients with early-stage endometrial cancer

OBJECTIVE

To investigate the combined predictive value of the preoperative serum cancer antigen 125 (CA125) level and age at diagnosis among patients with early-stage endometrial cancer (EC) after initial treatment.

METHODS

We retrospectively analyzed data from patients with early-stage EC from 1999 to 2015 in multiple institutions in China. All 447 patients received postoperative adjuvant radiotherapy for FIGO 2009 stage I and II EC with complete data on preoperative serum CA125 levels. All patients were divided into four groups according to the ESMO-ESGO-ESTRO risk classification. The predictive probability of 5-year overall survival (OS) and the sensitivity and specificity of CA125 and age were calculated.

RESULTS

The median follow-up time was 59 months (3-201 months). The 5-year OS and disease-free survival rates were 94.4% and 89.1%. Multivariate analysis showed that the preoperative CA125 level and age at diagnosis were independent prognostic factors for 5-year OS. The area under the curve for CA125 combined with age at diagnosis for 5-year OS was .692, and the corresponding sensitivity and specificity were 68.2% and 68.2% (p < .002), which were significantly better than the corresponding values for CA125 or age alone. After all 447 patients were divided into four groups according to CA125 combined with age, the 5-year OS of the elderly and higher CA125 group was only 73.7%.

CONCLUSIONS

Although preoperative CA125 had limited sensitivity in predicting the prognosis for early-stage EC after initial treatment, it remains a useful serum marker for risk assessment of early-stage EC. Combining CA125 with age may increase its predictive sensitivity.

Preoperative Prognostic Nutritional Index Is a Prognostic Indicator of Cancer-Specific Survival in Patients Undergoing Endometrial Cancer Surgery

BACKGROUND

The prognostic nutritional index (PNI) reflects systemic inflammation and nutritional status. This study aimed to evaluate the effect of preoperative PNI on postoperative cancer-specific survival in patients with endometrial cancer (EC).

METHODS

Demographic, laboratory, and clinical data were retrospectively collected from 894 patients who underwent surgical resection of EC. Preoperative PNIs were determined from the serum albumin concentration and total lymphocyte count, which were measured within 1 month before surgery. Patients were classified into high PNI (n = 619) and low PNI (n = 275) groups according to the preoperative PNI cut-off value of 50.6. The stabilized inverse probability of treatment weighting (IPTW) method was used to reduce bias: a weighting cohort divided into high PNI (n = 615.4) and low PNI (n = 272.3) groups. The primary outcome measure was postoperative cancer-specific survival.

RESULTS

The postoperative cancer-specific survival rate was higher in the high PNI group than the low PNI group in the unadjusted cohort (93.1% vs. 81.5%; proportion difference [95% confidence interval; 95% CI], 11.6% [6.6-16.6%]; P < 0.001) and in the IPTW-adjusted cohort (91.4% vs. 86.0%; 5.4% [0.8-10.2%]; P = 0.021). In the multivariate Cox proportional hazard regression model in the IPTW-adjusted cohort, high preoperative PNI (hazard ratio [95% CI], 0.60 [0.38-0.96]; P = 0.032) was an independent determinant of postoperative cancer-specific mortality. The multivariate-adjusted restricted cubic spline curve for the Cox regression model showed a significant negative association between preoperative PNI and postoperative cancer-specific mortality (P < 0.001).

CONCLUSION

High preoperative PNI was associated with improved postoperative cancer-specific survival in patients undergoing surgery for EC.

CA125 as a predictor of endometrial cancer lymphovascular space invasion and lymph node metastasis for risk stratification in the preoperative setting

Endometrial cancer (EC) is the most common malignancy of the female reproductive system. Cancer antigen 125 (CA125) is a serum tumor marker widely reported in EC patients, particularly those with poor prognostic factors such as grade 3 tumors, deep myometrial invasion, lymph node metastasis (LNM), and extra-uterine disease. This retrospective study stratifies pre-operative CA125 levels to evaluate odds ratios (OR) and relative risk (RR) between CA125 levels and the likelihood of +LNM, lymphovascular space invasion (LVSI), grade, and stage. Patient charts for women 18 years or older with a diagnosis of EC and pre-operative or within one week CA125 measurement from January 2000 to January 2015 at a regional hospital were reviewed. OR and RR were determined by unconditional maximum likelihood estimation for CA125 levels as the predictor with staging, grade, +LVSI and +LNM as outcomes. The largest increase in risk for patients having stage I/II/III disease was 52% greater (1.52-fold risk) while largest increase in risk for patients having stage III/IV disease was 67% greater (1.67-fold risk), both at CA125 ≥ 222U/ml. Patients with CA125 ≥ 122U/ml had significantly increased risk of +LNM, with maximum increase in risk of 98% (1.98-fold risk) at 222U/ml. Patients with CA125 ≥ 175U/ml had significantly increased risk of +LVSI, with maximum increase in risk of 39% (1.39-fold risk) at 222U/ml. This study shows that elevated CA125 levels correspond to increased stage, +LVSI, and +LNM in patients with EC.

What is the predictive value of preoperative CA 125 level on the survival rate of type 1 endometrial cancer?

Background/aim

To investigate the utility of preoperative serum cancer antigen 125 (CA 125) levels in type 1 endometrial carcinoma (EC) as a marker for determining poor prognostic factors and survival.

Material and methods

All patients with endometrial cancer, who had been treated between 2012 and 2020, were retrospectively reviewed, and finally, 256 patients with type 1 endometrium carcinoma were included in the study. The relationship between the clinicopathological characteristics, CA 125 level, and survival rates were analyzed. The cut-off value for the preoperative serum CA 125 level was defined as 16 IU/L.

Results

The median serum CA 125 levels were significantly higher in patients with deep myometrial invasion, lymph node metastasis, lymphovascular space invasion, cervical stromal and adnexal involvement, advanced stage, positive peritoneal cytology, recurrence, and adjuvant therapy requirement. Serum CA 125 cut-off values determined according to clinicopathologic factors ranged from 15.3 to 22.9 IU/L (sensitivity 61%–77%, specificity 52%–73%). The disease-specific survival rate was significantly higher in patients with CA 125 levels < 16 IU/L (P = 0.047).

Conclusion

The data showed that choosing a lower threshold value for the CA 125 level (16 IU/L) instead of 35 IU/L, could be more useful in type 1 EC patients with negative prognostic factors.

CA125 and Ovarian Cancer: A Comprehensive Review

Simple Summary

CA125 has been the most promising biomarker for screening ovarian cancer; however, it still does not have an acceptable accuracy in population-based screening for ovarian cancer. In this review article, we have discussed the role of CA125 in diagnosis, evaluating response to treatment and prognosis of ovarian cancer and provided some suggestions in improving the clinical utility of this biomarker in the early diagnosis of aggressive ovarian cancers. These include using CA125 to screen individuals with symptoms who seek medical care rather than screening the general population, increasing the cutoff point for the CA125 level in the plasma and performing the test at point-of-care rather than laboratory testing. By these strategies, we would detect more aggressive ovarian cancer patients in stages that the tumour can be completely removed by surgery, which is the most important factor in redusing recurrence rate and improving the survival of the patients with ovarian cancer.

Abstract

Ovarian cancer is the second most lethal gynecological malignancy. The tumour biomarker CA125 has been used as the primary ovarian cancer marker for the past four decades. The focus on diagnosing ovarian cancer in stages I and II using CA125 as a diagnostic biomarker has not improved patients’ survival. Therefore, screening average-risk asymptomatic women with CA125 is not recommended by any professional society. The dualistic model of ovarian cancer carcinogenesis suggests that type II tumours are responsible for the majority of ovarian cancer mortality. However, type II tumours are rarely diagnosed in stages I and II. The recent shift of focus to the diagnosis of low volume type II ovarian cancer in its early stages of evolution provides a new and valuable target for screening. Type II ovarian cancers are usually diagnosed in advanced stages and have significantly higher CA125 levels than type I tumours. The detection of low volume type II carcinomas in stage IIIa/b is associated with a higher likelihood for optimal cytoreduction, the most robust prognostic indicator for ovarian cancer patients. The diagnosis of type II ovarian cancer in the early substages of stage III with CA125 may be possible using a higher cutoff point rather than the traditionally used 35 U/mL through the use of point-of-care CA125 assays in primary care facilities. Rapid point-of-care testing also has the potential for effective longitudinal screening and quick monitoring of ovarian cancer patients during and after treatment. This review covers the role of CA125 in the diagnosis and management of ovarian cancer and explores novel and more effective screening strategies with CA125.

Diagnostic Accuracy of Clinical Biomarkers for Preoperative Prediction of Lymph Node Metastasis in Endometrial Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

In endometrial carcinoma (EC), preoperative classification is based on histopathological criteria, with only moderate diagnostic performance for the risk of lymph node metastasis (LNM). So far, existing molecular classification systems have not been evaluated for prediction of LNM. Optimized use of clinical biomarkers as recommended by international guidelines might be a first step to improve tailored treatment, awaiting future molecular biomarkers.

AIM

To determine the diagnostic accuracy of preoperative clinical biomarkers for the prediction of LNM in endometrial cancer.

METHODS

A systematic review was performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Studies identified in MEDLINE and EMBASE were selected by two independent reviewers. Included biomarkers were based on recommended guidelines (cancer antigen 125 [Ca-125], lymphadenopathy on magnetic resonance imaging, computed tomography, and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography [¹⁸FDG PET-CT]) or obtained by physical examination (body mass index, cervical cytology, blood cell counts). Pooled sensitivity, specificity, area under the curve (AUC), and likelihood ratios were calculated with bivariate random-effects meta-analysis. Likelihood ratios were classified into small (0.5-1.0 or 1-2.0), moderate (0.2-0.5 or 2.0-5.0) or large (0.1-0.2 or ≥ 5.0) impact.

RESULTS

Eighty-three studies, comprising 18,205 patients, were included. Elevated Ca-125 and thrombocytosis were associated with a moderate increase in risk of LNM; lymphadenopathy on imaging with a large increase. Normal Ca-125, cytology, and no lymphadenopathy on ¹⁸FDG PET-CT were associated with a moderate decrease. AUCs were above 0.75 for these biomarkers. Other biomarkers had an AUC <0.75 and incurred only small impact.

CONCLUSION

Ca-125, thrombocytosis, and imaging had a large and moderate impact on risk of LNM and could improve preoperative risk stratification.

IMPLICATIONS FOR PRACTICE

Routine lymphadenectomy in clinical early-stage endometrial carcinoma does not improve outcome and is associated with 15%-20% surgery-related morbidity, underlining the need for improved preoperative risk stratification. New molecular classification systems are emerging but have not yet been evaluated for the prediction of lymph node metastasis. This article provides a robust overview of diagnostic performance of all clinical biomarkers recommended by international guidelines. Based on these, at least measurement of cancer antigen 125 serum level, assessment of thrombocytosis, and imaging focused on lymphadenopathy should complement current preoperative risk stratification in order to better stratify these patients by risk.

The prognostic role of preoperative serum CA125 levels in patients with advanced endometrial carcinoma

BACKGROUND

Lifetime risk of developing endometrial cancer is 2.17%. There is controversy regarding the predictive value of Cancer Antigen 125 (CA125) in endometrial cancer as well as the significance of its relationship with prognostic factors and appropriate cut-off value.

OBJECTIVE

The aim of the present study was to investigate the prognostic role of CA125 in advanced endometrial carcinoma and determination of the appropriate cut-off value.

METHODS

A sample of 91 patients was retrospectively selected from a population of 501 patients suffering from endometrial cancer during 1995 to 2015 in accordance with the inclusion criteria. The relation between clinicopathological variables and CA125 were analyzed. In order to determine sensitivity and specificity of various cut-off levels, receiver operating characteristic (ROC) curve analysis was performed for associated factors confirmed by logistic regression analysis.

RESULTS

In 35% of patients, CA125 values were 35 u/ml, and in 52%, the values were equal to or greater than 20 u/ml. High preoperative CA125 was significantly related with advanced stage, ovarian involvement, omental metastasis, and myometrial invasion equal to or greater than 50%. According to the ROC curve, the suitable cut-off value for CA125 in advanced stage (sensitivity = 73%, specificity = 55%, positive predictive value = 18%, negative predictive value = 78%) and myometrial invasion equal to or greater than 50% (sensitivity = 64%, specificity = 61%, positive predictive value = 47%, negative predictive value = 74%) was 20 u/ml. Further, the suitable cut-off value for CA125 in involvement of the ovaries (sensitivity = 77%, specificity = 72%, positive predictive value = 31%, negative predictive value = 95%) and omental involvement (sensitivity = 70%, specificity = 70%, positive predictive value = 22%, negative predictive value = 95%) was 35 u/ml.

CONCLUSIONS

In endometrial carcinoma, due to the relationship of CA125 with numerous prognostic factors, it is recommended that CA125 measurement be included in preoperative evaluation. In case of high CA125 levels, complete surgical staging including lymphadenectomy and omentectomy should be considered.

Predicting Model of Lymph Node Metastasis Using Preoperative Tumor Grade, Transvaginal Ultrasound, and Serum CA-125 Level in Patients With Endometrial Cancer

OBJECTIVE

The purpose of this study was to evaluate the predicting model for lymph node metastasis using preoperative tumor grade, transvaginal sonography (TVS), and serum cancer antigen 125 (CA-125) level in patients with endometrial cancer.

MATERIALS AND METHODS

Between January 2000 and February 2013, we identified 172 consecutive patients with surgically staged endometrial cancer. Transvaginal sonography was performed by an expert gynecologic radiologist in all patients. All patients had complete staging surgery including total hysterectomy with bilateral pelvic and para-aortic lymphadenectomy and were staged according to the 2009 International Federation of Gynecology and Obstetrics classification. Various clinicopathologic data were obtained from medical records and were retrospectively analyzed.

RESULTS

Of 172 patients, 138 patients presented with stage I (118 IA and 20 IB), 12 had stage II, 18 had stage III (2 IIIA, 1 IIIB, 8 IIIC1, and 7 IIIC2), and 2 had stage IV diseases. Most patients had endometrioid adenocarcinoma (88.4%), and others (12.6%) had nonendometrioid histology. Eighteen patients (10.5%) were found to have lymph node metastasis. Deep myometrial invasion on preoperative TVS (≥50%), high serum CA-125 level (≥ 35 IU/mL), preoperative grade 2 or 3 tumors were significant preoperative factors predicting lymph node metastasis. There was no significant association between preoperative histology and lymph node metastasis. We calculated the simple model predicting lymph node metastasis based on preoperative tumor grade, TVS findings, and CA-125 level using logistic regression analysis. The sensitivity and specificity of this model were 94% and 57%, respectively (area under the curve, 0.84; 95% confidence interval [CI], 0.74-0.93; P < 0.01).

CONCLUSIONS

Preoperative tumor grade, myometrial invasion on preoperative TVS, and CA-125 can accurately predict lymph node metastasis in patients with endometrial cancer. The current study suggests the possibility that TVS could be positively used for preoperative evaluation strategy in the low-resource countries instead of expensive imaging modalities such as magnetic resonance imaging or positron emission tomography-computed tomography.

Novel algorithm including CA-125, HE4 and body mass index in the diagnosis of endometrial cancer

OBJECTIVES

To evaluate the diagnostic and prognostic potential of preoperative serum CA-125 and HE4 levels in patients with endometrial cancer.

METHODS

Prospective case-control study of 133 women who underwent surgical treatment at the University Medical Centre Ljubljana (64 patients with endometrial cancer, 69 control patients with prolapsed uterus or myoma). Serum CA-125 and HE4 levels were determined using electrochemiluminescent assays.

RESULTS

Serum CA-125 and HE4 levels were significantly higher in patients with endometrial cancer, compared to the controls (p=2.67×10^-4, 1.36×10^-7, respectively). A diagnostic model that combines serum CA-125 and HE4 levels and body mass index separated patients with endometrial cancer from controls, with AUC of 0.804, sensitivity of 66.7%, and specificity of 84.6%. Serum HE4 levels showed good prognostic potential and stratified the patients according to presence/absence of deep myometrial invasion (p=0.001) or lymphovascular invasion (p=0.003), with AUCs of 0.78 and 0.81, respectively. In low-risk patients with grade 1 and 2 endometrioid cancer for whom lymphadenectomy can be avoided, HE4 allowed stratification according to deep myometrial invasion (p=3.39×10^-4), with AUC of 0.84. Although median HE4 levels were higher in patients with lymphovascular invasion, this difference did not reach significance (p=0.06).

CONCLUSIONS

A model based on preoperative serum CA-125 and HE4 levels and body mass index has good diagnostic accuracy for separation of patients with endometrial cancer and control patients. In patients with endometrial cancer, serum HE4 levels allow prediction of deep myometrial and lymphovascular invasion.

The Value of Preoperative CA 125 Levels in Prediction of Myometrial Invasion in Patients with Early-stage Endometrioid- type Endometrial Cancer

AIM

To evaluate the relationship between pre-operative CA-125 levels and myometrial invasion in patients with early-stage endometrioid-type endometrial cancer.

MATERIALS AND METHODS

Two-hundred and sixty patients were diagnosed with endometrial cancer between January 2007 and December 2012. Of these, 136 patients with stage 1 endometrioid histologic-type and documented pre-operative serum CA-125 levels were included in the study. Age, preoperative CA-125 level, histologic grade, surgical grade, and presence of deep myometrial invasion were recorded. Additionally, 16, 20, and 35 IU/ml cutoff values were used and compared to evaluate the relationship between pre-operative CA-125 levels and myometrial invasion.

RESULTS

The average serum CA-125 level was 35.4±36.7 in patients with deep myometrial invasion, and 21.5±35.8 in cases without deep myometrial invasion. The relationship between the presence of deep myometrial invasion and CA-125 cut-off values (16, 20, 35 IU/ml) was statistically significant, although the correlation was weak (p<0.05). When the relationship between 16, 20 and 35 IU/ml CA-125 cut-off values and the presence of deep myometrial invasion was studied, specifity and sensitivity values were identified as: 0.60-0.68 for 16 IU/ml; 0.73-0.48 for 20 IU/ml; and 0.89-0.33 for 35 IU/ml. The sensitivity of 16 IU/ml cut-off value was higher when compared to other values.

CONCLUSIONS

This study demonstrates that preoperative serum CA-125 values maybe used as a predictive test in patients with early stage endometrioid-type endometrium cancer, and as a prognostic factor alone. Further studies should be conducted to identify different CA-125 cut-off values in patients with low risk endometrial cancer.

A preoperative and intraoperative scoring system to predict nodal metastasis in endometrial cancer

OBJECTIVE

To develop a scoring system that guides surgical decision-making regarding the need to perform lymphadenectomy.

METHODS

A retrospective study was performed of patients who underwent complete surgical staging of endometrial cancer between 2003 and 2014 at three centers in Brazil. Preoperative and intraoperative risk factors were used to develop a scoring system to predict lymph node metastasis.

RESULTS

Among 329 patients included, 71 (21.6%) had positive lymph nodes and 259 (78.4%) had negative lymph nodes. The characteristics associated with nodal metastasis in univariate analysis included the level of cancer antigen 125 (P<0.001), preoperative histological grade (P<0.001), endometrial thickness (P=0.012), and pathologic features including tumor size (P<0.001), tumor extension (P<0.001), and lower uterine segment involvement (P<0.001). On multivariate logistic regression analysis, tumor grade, tumor extension, and lower uterine segment involvement remained significantly associated. The resulting scoring system showed good accuracy as demonstrated by an area under the receiver operating characteristic curve of 0.858 (95% confidence interval 0.804-0.913).

CONCLUSION

A highly accurate scoring system for the prediction of lymph node metastasis was developed on the basis of three preoperative and intraoperative risk factors. After validation, this model could greatly aid clinicians in the surgical management of endometrial cancer.

Utility of Preoperative CA125 Assay in the Management Planning of Women Diagnosed with Uterine Cancer

Objective. This study assesses the role of preoperative serum CA125 levels in the planning treatment options for women diagnosed with uterine cancer. Material and Method. Ninety five consecutive patients diagnosed with uterine cancer during a four-year period were identified. Age ranged from 35 to 89 years with a mean age of 69 years. The preoperative CA125 levels were dichotomised at 28 U/mL (using ROC analysis to identify the best discriminating threshold for 5-year survival). This level was then correlated with preoperative prognostic indicators: patient age, tumour grade, and histopathological tumour cell type. Survival data was plotted using Kaplan-Meier curves and analysed using the log-rank test. Univariate and multivariate analysis were performed to identify the predictors of overall survival. Results. The mean age of patients was 69 years (range: 35-89). On univariate analysis, the use of preoperative CA125 levels of greater or less than 28 U/mL correlated significantly with age (P = 0.01), the grade of disease (P = 0.02) and unfavourable tissue type (P = 0.03). This threshold CA125 level had a sensitivity of 75%, specificity of 76%, positive predictive value of 35% and negative predicative value of 96.25%, and a likelihood ratio of 3.12 for predicting nodal disease. Using a threshold of preoperative CA125 level of 28 U/mL (area under curve: 0.60) was also a significant predictor of 5-year survival (log-rank test, P = 0.01). Using Cox multivariate survival analysis to identify predictive preoperative factors overall, unfavourable cell type was the strongest predictor of survival (Chi square = 36.5, df = 4, and P = 0.001), followed by preoperative CA125 level (CA125 > 28 U/mL, P = 0.011) and unfavourable preoperative grade (P = 0.017). Amongst patients with a favourable histological tissue type (endometrioid), preoperative CA125 levels predicted overall survival (Chi square = 6.039, df = 2, P = 0.02); however unfavourable preoperative grade did not (P = 0.5). Overall, at five-year follow-up, while there were no deaths among the women with preoperative serum CA125 less than 12 U/mL, eleven of the twenty-three deaths (47.82%) in the study occurred in women with a preoperative CA125 more than 28 U/mL. Conclusions. A preoperative CA125 assay for women with uterine cancer is a relatively inexpensive, reproducible, and objective test which provides valuable information regarding the risk of metastatic disease and overall likelihood of long term survival. Patients with a low likelihood of metastatic/nodal disease (favourable tissue type and CA125 level < 28 U/mL) and significant comorbidities may benefit from avoiding an extended complete staging procedure. Alternatively, a high level of CA125 may prompt further imaging and multidisciplinary discussions to plan for individualised management and consideration for recruitment to clinical trials.

Amino acid profile index for early detection of endometrial cancer: verification as a novel diagnostic marker

BACKGROUND

Plasma amino acid profiles (PAAPs) vary in individual cancer patients, and it has been suggested that they may be useful for early detection of several types of cancer. We evaluated the diagnostic performance of a profile index for endometrial cancer composed of multiple plasma amino acids as a novel biomarker and compared its diagnostic performance with that of CA125.

METHODS

Plasma amino acid levels of 80 patients with endometrial cancer, 122 with benign gynecological diseases, and 240 age- and body mass index-matched control subjects were measured using liquid chromatography and mass spectrometry. After univariate analysis, we applied a multiplex model based on the PAAP multivariate analysis to distinguish patients with endometrial cancer from control subjects. We compared the diagnostic performance of the multiple PAAP index (API) with that of CA125.

RESULTS

The levels of several plasma amino acids were significantly different in patients with endometrial cancer. The area under the receiver operating characteristic curves (AUC) used to distinguish endometrial cancer patients from control subjects was 0.94. The AUC for API was significantly larger than that for CA125 (P = 0.0068). For the same specificity of 98.3 %, API showed a significantly higher sensitivity (60.0 %, 95 % CI, 43.3-75.1) than that of CA125 (22.5 %, 95 % CI, 10.1-38.5). In stage I cases, API showed significantly higher positivity than that of CA125 (P = 0.0002).

CONCLUSIONS

The sensitivity and disease specificity of API for early-stage detection of endometrial cancer was superior to CA125. This novel plasma biomarker has the potential to become a diagnostic and screening marker for endometrial cancer.