Investigating the Current Harmonization Status of Tumor Markers Using Global External Quality Assessment Programs: A Feasibility Study.

BACKGROUND: The harmonization status of most tumor markers (TMs) is unknown. We report a feasibility study performed to determine whether external quality assessment (EQA) programs can be used to obtain insights into the current harmonization status of the tumor markers α-fetoprotein (AFP), prostate specific antigen (PSA), carcinoembryonic antigen (CEA), cancer antigen (CA)125, CA15-3 and CA19-9. METHODS: EQA sample results provided by 6 EQA providers (INSTAND [Germany], Korean Association of External Quality Assessment Service [KEQAS, South Korea], National Center for Clinical Laboratories [NCCL, China], United Kingdom National External Quality Assessment Service [UK NEQAS, United Kingdom], Stichting Kwaliteitsbewaking Medische Laboratoriumdiagnostiek [SKML, the Netherlands], and the Royal College of Pathologists of Australasia Quality Assurance Programs [RCPAQAP, Australia]) between 2020 and 2021 were used. The consensus means, calculated from the measurement procedures present in all EQA programs (Abbott Alinity, Beckman Coulter DxI, Roche Cobas, and Siemens Atellica), was used as reference values. Per measurement procedure, the relative difference between consensus mean for each EQA sample and the mean of all patient-pool-based EQA samples were calculated and compared to minimum, desirable, and optimal allowable bias criteria based on biological variation. RESULTS: Between 19040 (CA15-3) and 25398 (PSA) individual results and 56 (PSA) to 76 (AFP) unique EQA samples were included in the final analysis. The mean differences with the consensus mean of patient-pool-based EQA samples for all measurement procedures were within the optimum bias criterion for AFP, the desirable bias for PSA, and the minimum bias criterion for CEA. However, CEA results <8 µg/L exceeded the minimum bias criterion. For CA125, CA15-3, and CA19-9, the harmonization status was outside the minimum bias criterion, with systematic differences identified. CONCLUSIONS: This study provides relevant information about the current harmonization status of 6 tumor markers. A pilot harmonization investigation for CEA, CA125, CA15-3, and CA19-9 would be desirable.

Ambulatory human chorionic gonadotrophin (hCG) testing: a verification of two hCG point of care devices.

OBJECTIVES: Quantitative human chorionic gonadotropin (hCG) measurements are used to manage women classified with a pregnancy of unknown location (PUL). Two point of care testing (POCT) devices that quantify hCG are commercially available. We verified the i-STAT 1 (Abbott) and the AQT 90 FLEX (Radiometer) prior to use in PUL triage. METHODS: Tests for precision, external quality assurance (EQA), correlation, hook effect and recovery were undertaken alongside a POCT usability assessment during this prospective multi-center verification. RESULTS: Coefficients of variation ranged between 4.0 and 5.1 % for the three i-STAT 1 internal quality control (IQC) solutions and between 6.8 and 7.3 % for the two AQT IQC solutions. Symmetric differences in POCT EQA results when compared with laboratory and EQA stock values ranged between 3.2 and 24.5 % for the i-STAT 1 and between 3.3 and 36.9 % for the AQT. Correlation coefficients (i-STAT 1: 0.96, AQT: 0.99) and goodness of fit curves (i-STAT 1: 0.92, AQT: 0.99) were excellent when using suitable whole blood samples. An hCG hook effect was noted with the i-STAT 1 between 572,194 and 799,089 IU/L, lower than the hook effect noted with the AQT, which was between 799,089 and 1,619,309 IU/L. When hematocrit concentration was considered in sample types validated for use with each device, hCG recovery was 108 % with the i-STAT 1 and 98 % with the AQT. The i-STAT 1 scored lower on usability overall (90/130) than the AQT (121/130, p<0.001, Mann-Whitney). CONCLUSIONS: Both hCG POCT devices were verified for use in clinical practice. Practical factors must also be considered when choosing which device to use in each unit.

External quality assessment-based tumor marker harmonization simulation; insights in achievable harmonization for CA 15-3 and CEA.

OBJECTIVES: CA 15-3 and CEA are tumor markers used in routine clinical care for breast cancer and colorectal cancer, among others. Current measurement procedures (MP) for these tumor markers are considered to be insufficiently harmonized. This study investigated the achievable harmonization for CA 15-3 and CEA by using an in silico simulation of external quality assessment (EQA) data from multiple EQA programs using patient-pool based samples. METHODS: CA 15-3 and CEA data from SKML (2021), UK NEQAS (2020-2021) and KEQAS (2020-2021) were used. A harmonization protocol was defined in which MPs that were considered equivalent were used to value assign EQA samples, and recalibration was only required if the MP had a bias of >5 % with value assigned EQA. Harmonization status was assessed by determining the mean level of agreement and residual variation by CV (%). RESULTS: Only MPs from Abbott, Beckman, Roche and Siemens were available in all EQA programs. For CA 15-3, recalibration was proposed for Beckman MP only and for CEA, recalibration was proposed for Siemens MP only. When the harmonization procedures were applied, for CA 15-3 the pre-harmonization mean bias range per MP was reduced from -29.28 to 9.86 %, into -0.09-0.12 % after harmonization. For CEA, the mean bias range per MP was reduced from -23.78 to 2.00 % pre-harmonization to -3.13-1.42 % post-harmonization. CONCLUSIONS: The present study suggests that a significant improvement in the harmonization status of CA 15-3 and CEA may be achieved by recalibration of a limited number of MPs.

PREDICT-GTN 1: Can we improve the FIGO scoring system in gestational trophoblastic neoplasia?

Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.

Predictors for single-agent resistance in FIGO score 5 or 6 gestational trophoblastic neoplasia: a multicentre, retrospective, cohort study.

BACKGROUND: Patients with gestational trophoblastic neoplasia who have an International Federation of Gynaecology and Obstetrics (FIGO) risk score of 5 or 6 usually receive non-toxic single-agent chemotherapy as a first-line treatment. Previous studies suggest that only a third of patients have complete remission, with the remaining patients requiring toxic multiagent chemotherapy to attain remission. As stratification factors are unknown, some centres offer multiagent therapy upfront, resulting in overtreatment of many patients. We aimed to identify predictive factors for resistance to single-agent therapy to inform clinicians on which patients presenting with a FIGO score of 5 or 6 are likely to benefit from upfront multiagent chemotherapy. METHODS: We did a multicentre, retrospective, cohort study of patients with gestational trophoblastic neoplasia presenting with a FIGO score of 5 or 6, who received treatment at three gestational trophoblastic neoplasia reference centres in the UK, Brazil, and the USA between Jan 1, 1964, and Dec 31, 2018. All patients who had been followed up for at least 12 months after remission were included. Patients were excluded if they had received a non-standard single-agent treatment (eg, etoposide); had been given a previously established first-line multiagent chemotherapy regimen; or had incomplete data for our analyses. Patient data were retrieved from medical records. The primary outcome was the incidence of chemoresistance after first-line or second-line single-agent chemotherapy. Variables associated with chemoresistance to single-agent therapies were identified by logistic regression analysis. In patient subgroups defined by choriocarcinoma histology and metastatic disease status, we did bootstrap modelling to define thresholds of pretreatment human chorionic gonadotropin concentrations and identify groups of patients with a greater than 80% risk (ie, a positive predictive value [PPV] of 0·8) of resistance to single-agent chemotherapy. FINDINGS: Of 5025 patients with low-risk gestational trophoblastic neoplasia, we identified 431 patients with gestational trophoblastic neoplasia presenting with a FIGO risk score of 5 or 6. All patients were followed up for a minimum of 2 years. 141 (40%) of 351 patients developed resistance to single-agent treatments and required multiagent chemotherapy to achieve remission. Univariable and multivariable logistic regression revealed metastatic disease status (multivariable logistic regression analysis, odds ratio [OR] 1·9 [95% CI 1·1-3·2], p=0·018), choriocarcinoma histology (3·7 [1·9-7·4], p=0·0002), and pretreatment human chorionic gonadotropin concentration (2·8 [1·9-4·1], p<0·0001) as significant predictors of resistance to single-agent therapies. In patients with no metastatic disease and without choriocarcinoma, a pretreatment human chorionic gonadotropin concentration of 411 000 IU/L or higher yielded a PPV of 0·8, whereas in patients with either metastases or choriocarcinoma, a pretreatment human chorionic gonadotropin concentration of 149 000 IU/L or higher yielded the same PPV for resistance to single-agent therapy. INTERPRETATION: Approximately 60% of women with gestational trophoblastic neoplasia presenting with a FIGO risk score of 5 or 6 achieve remission with single-agent therapy; almost all remaining patients have complete remission with subsequent multiagent chemotherapy. Primary multiagent chemotherapy should only be given to patients with metastatic disease and choriocarcinoma, regardless of pretreatment human chorionic gonadotropin concentration, or to those defined by our new predictors. FUNDING: None. TRANSLATION: For the Portuguese translation of the abstract see Supplementary Materials section.

Following chemotherapy for gestational trophoblastic neoplasia, do residual lung lesions increase the risk of relapse?

BACKGROUND: There remains uncertainty about the prognostic significance of residual lung lesion on imaging after completion of treatment of low- or high-risk gestational trophoblastic neoplasia (GTN). Here, we determine if such residual lung lesions are associated with an increased risk of relapse. METHODS: We retrospectively screened our electronic database to identify patients with low- or high-risk GTN and lung metastases between 2004 and 18. Recurrences among patients with or without residual lung lesions on imaging were compared. Chi square analysis and Kaplan-Meier survival curves were constructed. As the numbers of cases were low, we combined this data with our previously published and non-overlapping patient cohort (1995-2004). RESULTS: Of 1304 GTN patients treated at our centre between 2004 and 18, 99 had lung metastases without other distant sites. There were 40 patients (40.4%) with residual lung lesions. Whilst an increased rate of relapse was observed among patients with residual lung lesions (4/40; 10.0%) compared to without such lesions (3/59; 5.1%), this difference was not statistically significant (p = .35). By combining the data with our previous cohort, there was an increase in relapse rate of patients with residual lung lesions (5/63; 7.9%) compared to those without such lesions (4/112; 3.6%). However, this difference was also not statistically significant (p = .21). CONCLUSION: Residual lung lesions on imaging after completion of GTN treatment are common. However, this finding did not statistically increase relapse rate. Due to low number of recurrent events, a multi-centre, larger dataset would be needed to provide more definitive evidence.