Relevance of prognostic index with β2-microglobulin for patients with diffuse large B-cell lymphoma in the rituximab era

Revisiting beta-2 microglobulin as a prognostic marker in diffuse large B-cell lymphoma

BACKGROUND

Several clinical prognostic models for diffuse large B-cell lymphoma (DLBCL) have been proposed, including the most commonly used International Prognostic Index (IPI), the National Comprehensive Cancer Network IPI (NCCN-IPI), and models incorporating beta-2 microglobulin (β2M). However, the role of β2M in DLBCL patients is not fully understood.

METHODS

We identified 6075 patients with newly diagnosed DLBCL treated with immunochemotherapy registered in the Danish Lymphoma Registry.

RESULTS

A total of 3232 patients had data available to calculate risk scores from each of the nine considered risk models for DLBCL, including a model developed from our population. Three of four models with β2M and NCCN-IPI performed better than the International Prognostic Indexes (IPI, age-adjusted IPI, and revised IPI). Five-year overall survival for high- and low-risk patients were 43.6% and 86.4% for IPI and 34.9% and 96.2% for NCCN-IPI. In univariate analysis, higher levels of β2M were associated with inferior survival, higher tumor burden (advanced clinical stage and bulky disease), previous malignancy and increased age, and creatinine levels. Furthermore, we developed a model (β2M-NCCN-IPI) by adding β2M to NCCN-IPI (c-index 0.708) with improved discriminatory ability compared to NCCN-IPI (c-index 0.698, p < 0.05) and 5-year OS of 33.1%, 56.2%, 82.4%, and 96.4% in the high, high-intermediate, low-intermediate and low-risk group, respectively.

CONCLUSION

International Prognostic Indices, except for NCCN-IPI, fail to accurately discriminate risk groups in the rituximab era. β2M, a readily available marker, could improve the discriminatory performance of NCCN-IPI and should be re-evaluated in the development setting of future models for DLBCL.

Challenges identifying DLBCL patients with poor outcomes to upfront chemoimmunotherapy and its impact on frontline clinical trials

Diffuse large B cell lymphoma (DLBCL) has a variable course of disease among patients as it consists of subgroups that are clinically, biologically and molecularly heterogeneous. In this review, we will discuss how this heterogeneity has likely hindered the ability of traditional prognostic models to identify DLBCL patients at high risk of having poor outcomes with conventional upfront chemoimmunotherapy. We will highlight the challenges and downsides of using these models for risk stratification in clinical trials. Also, we present some of the novel prognosticators that have shown a prognostic value independently or when incorporated into existing prognostic models. Additionally, since the failure of frontline clinical trials to improve outcomes beyond R-CHOP chemoimmunotherapy may be at least partially explained by the restrictive eligibility criteria, risk stratification methods and the selection bias encountered due to the complexed logistics of clinical trials; we will discuss strategies to refine and modernize clinical trial design.

Beta2-microglobulin is a valuable marker and identifies a poor-prognosis subgroup among intermediate-risk patients with diffuse large B cell lymphoma

Prognosis of diffuse large B cell lymphoma (DLBCL) can be predicted by various factors. The most widely used tool for prediction is the international prognostic index (IPI). β2-microglobulin is a tumor marker commonly used in hematological malignancies. β2-microglobulin is well correlated with outcome of DLBCL. It has been used as an adjunctive tool in some scoring systems for prognostication of DLBCL. In this study, we collected data of patients with diagnosis of DLBCL between 2015 and 2019 in our institute. For each patient, IPI was calculated according to published literature. At diagnosis, serum levels of β2-microglobulin were measured in the clinical laboratory and the results were retrieved from medical records. A total of 516 patients (269 male and 247 female) were enrolled for retrospective analysis. The median age was 64 (range 22-96). The median follow-up period was 32.2 months. The median level of β2-microglobulin was 2319 μg/L (normal range < 2366 μg/L in the clinical laboratory). Level of β2-microglobulin was significantly different between survivors and patients who succumbed to the disease. β2-microglobulin level was correlated with tumor stage, extranodal involvement, B symptoms and IPI, suggesting that it may be a good surrogate marker for disease severity and outcome prediction. We selected the intermediate-risk patients for further analysis. Patients with intermediate-risk IPI and high β2-microglobulin levels have overall survival comparable to patients with high-risk IPI, suggesting an important role of β2-microglobulin in subdivision of DLBCL patients. In conclusion, β2-microglobulin levels correlated with outcome of DLBCL. It may be used independently as a prognostic factor. Subdivision of patients with intermediate-risk IPI may identify a group of high-risk patients, which can be helpful in refining plans of treatment and follow-up.

Development and validation of prediction model for overall survival in patients with lymphoma: a prospective cohort study in China

OBJECTIVE

The survival of patients with lymphoma varies greatly among individuals and were affected by various factors. The aim of this study was to develop and validate a prognostic model for predicting overall survival (OS) in patients with lymphoma.

METHODS

We conducted a prospective longitudinal cohort study in China between January 2014 and December 2018 (n = 1,594). After obtaining the follow-up data, we randomly split the cohort into the training cohort (n = 1,116) and the validation cohort (n = 478). The least absolute shrinkage and selection operator (LASSO) regression analysis was used to select the predictors of the model. Cox stepwise regression analysis was used to identify independent prognostic factors, which were finally displayed as static nomogram and web-based dynamic nomogram. We calculated the concordance index(C-index) to describe how the predicted survival of objectively confirmed prognosis. The calibration plot is used to evaluate the prediction accuracy and discrimination ability of the model. Net reclassification index (NRI) and decision curve analysis (DCA) curves were also used to evaluate the prediction ability and net benefit of the model.

RESULTS

Nine variables in the training cohort were considered to be independent risk factors for patients with lymphoma in the final model: age, Ann Arbor Stage, pathologic type, B symptoms, chemotherapy, targeted therapy, lactate dehydrogenase (LDH), β2-microglobulin and C-reactive protein (CRP). The C-indices of OS were 0.749 (95% CI, 0.729-0.769) in the training cohort and 0.731 (95% CI, 0.762-0.700) in the validation cohort. A good agreement between prediction by nomogram and actual observation was shown in the calibration curve for the probability of survival in both the training cohort and validation cohorts. The areas under curve (AUC) of the area under the receiver operating characteristic (ROC) curves for 1-year, 3-year, and 5-year OS were 0.813, 0.800, and 0.762, respectively, in the training cohort, and 0.802, 0.768, and 0.721, respectively, in the validation cohort. Compared with the Ann Arbor Stage system, NRI and DCA showed that the model had a higher predictive capacity and net benefit.

CONCLUSION

The prediction models reliably estimate the outcome of patients with lymphoma. The model had high discrimination and calibration, which provided a simple and reliable tool for the survival prediction of the patients, and it might help patients benefit from personalized intervention.

Clinical Characteristics, Outcomes, and Risk Factors for Patients with Diffuse Large B-Cell Lymphoma and Development of Nomogram to Identify High-Risk Patients

Objectives. To analyse the clinical features, outcomes, and risk factors of patients with diffuse large B-cell lymphoma (DLBCL) in China, with the aim to establish a new prognostic model based on risk factors. Methods. Clinical features and outcomes of 564 patients newly diagnosed with DLBCL from Jan 2009 to May 2017 were analyzed retrospectively. Variables were screened by LASSO regression and nomogram was constructed. Results. The 5-year overall survival (OS) of the cohort was 75%. The 5-year OS of patients differentiated by International Prognostic Index (IPI) score was 90% (score 0–2), 73% (score 3), and 51% (score 4-5), respectively. Age > 60, Eastern Cooperative Oncology Group (ECOG) > 1, Ann Arbor stage III-IV, bone marrow involvement, low level of albumin (ALB), and lymphatic/monocyte ratio (LMR) were independent predictors of OS. The predictive model was developed based on factors including age, bone marrow involvement, LMR, ALB, and ECOG scores. The predictive ability of the model (AUC, 0.77) was better than that of IPI (AUC, 0.74) and NCCN-IPI (AUC, 0.69). The 5-year OS of patients in the low-, intermediate-, and high-risk groups identified by the new predictive model was 89%, 70%, and 33%, respectively. Conclusions. The new prediction model had better predictive performance and could better identify high-risk patients.

18F-FDG cerebellum/liver index as a prognostic factor for progression-free survival in diffuse large B-cell lymphoma

OBJECTIVE

18F-FDG PET/CT provides valuable informations regarding the prognosis of DLBCL. The aim of this study is to test a novel index based on cerebellar uptake to predict progression free survival in DLBCL patients.

METHODS

Data from patients with de novo DLBCL between January 2011 and December 2018 were retrospectively collected and PFS was determined. The conventional PET parameters (SUVmax and total metabolic tumor volume) and the CLIP, corresponding to the ratio of the cerebellum SUVmax over the liver SUVmean, were extracted from baseline 18F-FDG PET.

RESULTS

Ninety-five patients were included. When using a threshold of 3.24, CLIP was a significant predictor of PFS on univariate analysis (HR 3.4, p < 0.001) with different 5-year survival rates: 68% (CLIP ≥ 3.24) versus 32% (CLIP < 3.24). Multivariate analysis confirmed the prognostic value of CLIP, as it is one of the two factors remaining significant with β2-microglobulin (HR 2.1 and 2.5 respectively, p = 0.04 and p = 0.03). A score associating β2-microglobulin and CLIP allowed to separate the population into three groups of different outcome in terms of 5-year PFS: low risk (80%), intermediate risk (42%) and high risk (17%).

CONCLUSIONS

The CLIP derived from pre-therapeutic 18F-FDG PET seems to be an interesting predictive marker of PFS in DLBCL treated by immunochemotherapy.

Statistical Challenges in Development of Prognostic Models in Diffuse Large B-Cell Lymphoma: Comparison Between Existing Models - A Systematic Review

Background and Aim

Based on advances in the diagnosis, classification, and management of diffuse large B-cell lymphoma (DLBCL), a number of new prognostic models have been proposed. The aim of this study was to review and compare different prognostic models of DLBCL based on the statistical methods used to evaluate the performance of each model, as well as to analyze the possible limitations of the methods.

Methods and Results

A literature search identified 46 articles that proposed 55 different prognostic models for DLBCL by combining different clinical, laboratory, and other parameters of prognostic significance. In addition, six studies used nomograms, which avoid risk categorization, to create prognostic models. Only a minority of studies assessed discrimination and/or calibration to compare existing models built upon different statistical methods in the process of development of a new prognostic model. All models based on nomograms reported the c-index as a measure of discrimination. There was no uniform evaluation of the performance in other prognostic models. We compared these models of DLBCL by calculating differences and ratios of 3-year overall survival probabilities between the high- and the low-risk groups. We found that the highest and lowest ratio between low- and high-risk groups was 6 and 1.31, respectively, while the difference between these groups was 18.9% and 100%, respectively. However, these studies had limited duration of follow-up and the number of patients ranged from 71 to 335.

Conclusion

There is no universal statistical instrument that could facilitate a comparison of prognostic models in DLBCL. However, when developing a prognostic model, it is recommended to report its discrimination and calibration in order to facilitate comparisons between different models. Furthermore, prognostic models based on nomograms are becoming more appealing owing to individualized disease-related risk estimations. However, they have not been validated yet in other study populations.

Systemic HD-MTX for CNS prophylaxis in high-risk DLBCL patients: a prospectively collected, single-center cohort analysis

We evaluated the efficacy of systemic high-dose methotrexate (HD-MTX) for CNS prophylaxis in a prospectively recruited cohort of DLBCL patients at high risk of CNS relapse. High-risk CNS relapse was defined as the involvement of ≥ 2 extranodal sites with elevated lactate dehydrogenase (LDH); CNS international prognostic index (CNS-IPI) ≥ 4; or involvement of high-risk extranodal sites, including bone marrow, breasts, testes, and paranasal sinuses. Overall, 130 patients who received at least two cycles of standard chemoimmunotherapy were evaluated; of these, 64 patients received additional systemic HD-MTX, either on day 15 of alternating cycles or 2-5 weeks after completion of primary therapy. Patients receiving HD-MTX showed a generally higher risk of CNS relapse than the other 66 patients not receiving prophylaxis. The estimated 2-year cumulative CNS relapse, progression-free survival and overall survival rates were 8.1%, 66.3%, and 77.5%, respectively, in patients who received systemic HD-MTX and 6.9%, 67.4%, and 71.4%, respectively, in patients without prophylaxis, with no significant between-group differences. Although this study does not show that systemic HD-MTX is definitively effective, these results may be of help to other researchers investigating the utility of HD-MTX prophylaxis in mitigating negative risk factors.

Available prognostic models for risk stratification of diffuse large B cell lymphoma patients: a systematic review

The International Prognostic Index (IPI) has been used for risk stratification for a long time in diffuse large B cell lymphoma (DLBCL). Based on new clinical and biological prognostic markers, many new prognostic models have been described. This review aims to present the progress in development and validation of these prognostic models. A comprehensive literature review was performed to identify studies that proposed a new prognostic model in DLBCL. A total of 38 studies met the inclusion criteria. The IPI, revised IPI (R-IPI), and National Comprehensive Cancer Network (NCCN)-IPI were the most studied prognostic indexes, externally validated and commonly used to compare to other models. Despite an increasing number of prognostic models have been proposed lately, most of them lack external validation. Further studies, that combine biological and clinical markers with prognostic significance, are needed to determine the optimal prognostic tool for more personalized treatment approach to DLBCL patients.

The pretreatment albumin to globulin ratio as a significant predictor in patients with diffuse large B cell lymphoma

BACKGROUND

The pretreatment albumin to globulin ratio (AGR) has been used to predict survival in several types of tumors. However, whether AGR can predict outcomes in patients with diffuse large B-cell lymphoma (DLBCL) remains unclear. We evaluated the prognosis value of AGR in DLBCL patients.

METHODS

We retrospectively analyzed the available serum biochemical results of 335 patients with newly diagnosed DLBCL before treatment. The AGR was calculated as: albumin (g/L)/globulin. X-tile program was used to generate an optimal cut-off value of 1.3 for AGR. And all patients were respectively divided into the low AGR and high AGR groups according to the cut-off value.

RESULTS

The low AGR group displayed more adverse clinical chacteristics, including old age, sex (female), increased β2-microglobulinpoor (β2-MG), increased lactate dehydrogenase (LDH), B symptoms, poor performance status (PS), advanced stage, number of extranodal sites ≥ 2 and higher International Prognostic Index (IPI). AGR was negatively correlated with age, IPI score, ECOG score, Ann Arbor stage, B symptoms, β2-MG, LDH, and extranodal involvement, while positively correlated with gender. Patients with a low AGR presented with significantly poorer overall survival (OS, P = .001). Multivariate analysis further demonstrated that a low AGR was an independent adverse predictor for OS (HR = 0.613; 95% CI = 0.412-0.910, P = .015). In addition, AGR distinguished patients with different prognosis in stage III-IV and the non-germinal center B cell-like lymphoma (non-GCB) groups, a low AGR was also significantly associated with poor OS in 2 groups.

CONCLUSION

Pretreatment AGR was a simple and effective clinical marker of survival in patients with DLBCL, and may had an additional prognostic value based on Ann Arbor stage and cell of origin for DLBCL.