Baseline and interim functional imaging with PET effectively risk stratifies patients with peripheral T-cell lymphoma

Prognostic Significance Of Sequential 18f-fdg Pet/Ct During Frontline Treatment Of Peripheral T Cell Lymphomas

BACKGROUND/AIMS

The prognostic significance of 18F-fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) in peripheral T-cell lymphomas (PTCLs) are controversial. We explored the prognostic impact of sequential 18F-FDG PET/CT during frontline chemotherapy of patients with PTCLs.

METHODS

In total, 143 patients with newly diagnosed PTCLs were included. Sequential 18F-FDG PET/CTs were performed at the time of diagnosis, during chemotherapy, and at the end of chemotherapy. The baseline total metabolic tumor volume (TMTV) was calculated using the the standard uptake value with a threshold method of 2.5.

RESULTS

A baseline TMTV of 457.0 cm3 was used to categorize patients into high and low TMTV groups. Patients with a requirehigh TMTV had shorter progression-free survival (PFS) and overall survival (OS) than those with a low TMTV (PFS, 9.8 vs. 26.5 mo, p = 0.043; OS, 18.9 vs. 71.2 mo, p = 0.004). The interim 18F-FDG PET/CT response score was recorded as 1, 2-3, and 4-5 according to the Deauville criteria. The PFS and OS showed significant differences according to the interim 18F-FDG PET/CT response score (PFS, 120.7 vs. 34.1 vs. 5.1 mo, p < 0.001; OS, not reached vs. 61.1 mo vs. 12.1 mo, p < 0.001).

CONCLUSION

The interim PET/CT response based on visual assessment predicts disease progression and survival outcome in PTCLs. A high baseline TMTV is associated with a poor response to anthracycline-based chemotherapy in PTCLs. However, TMTV was not an independent predictor for PFS in the multivariate analysis.

SOHO State-of-the-Art Updates and Next Questions: Treatment for Newly Diagnosed Peripheral T-Cell Lymphomas

Although a rare subset of non-Hodgkin lymphomas, peripheral T-cell lymphomas (PTCL) account for a disproportionate proportion of patient mortality. Conventional therapies are derived from experience treating aggressive B-cell lymphomas and center around CHOP-based chemotherapy. However, due to the unique biology and diverse subtypes of PTCL, most patients fail to durably respond to this approach and 5-year survival is only 20% to 30%. There have been multiple attempts to improve outcomes for patients with PTCL. Among the more successful strategies are the use of consolidative autologous stem cell transplant, the augmentation of CHOP with etoposide (CHOEP), and the use of brentuximab vedotin in CD30-positive PTCL. Advances in the understanding of histology-specific biology has cultivated enthusiasm to evaluate hypomethylating agents, histone deacetylate inhibitors, and phosphoinositol-3-kinase inhibitors in the frontline setting. Improvements in monitoring disease response and prognostication including the use of cell-free DNA, mutational profiling, and interim PET/CT imaging are also on the horizon. For patients with acute T-cell leukemia/lymphoma, the use of mogamulizumab-based therapy in the frontline setting may lead to advances in care. The true impact of these new-era therapies will only be elucidated as clinical practices incorporate the rapidly changing evidence.

Application of interim PET-CT in first-line treatment decision-making for lymphoma

Recent advances in lymphoma treatment have significantly improved the survival of patients; however, the current approaches also have varying side effects. To overcome these, it is critical to implement individualized treatment according to the patient's condition. Therefore, the early identification of high-risk groups and targeted treatment are important strategies for prolonging the survival time and improving the quality of life of patients. Interim positron emission tomography-computed tomography (PET-CT) has a high prognostic value, which can reflect chemosensitivity and identify patients for whom treatment may fail under this regimen. To date, many prospective clinical studies on interim PET (iPET)‍-adapted therapy have been conducted. In this review, we focus on the treatment strategies entailed in these studies, as well as the means and timing of iPET assessment, with the aim of exploring the efficacy and existing issues regarding iPET-adapted treatment. It is expected that the improved use of PET-CT examination can facilitate treatment decision-making to identify precise treatment options.

Quantitative PET-based biomarkers in lymphoma: getting ready for primetime

The use of functional quantitative biomarkers extracted from routine PET-CT scans to characterize clinical responses in patients with lymphoma is gaining increased attention, and these biomarkers can outperform established clinical risk factors. Total metabolic tumour volume enables individualized estimation of survival outcomes in patients with lymphoma and has shown the potential to predict response to therapy suitable for  risk-adapted treatment approaches in clinical trials. The deployment of machine learning tools in molecular imaging research can assist in recognizing complex patterns and, with image classification, in tumour identification and segmentation of data from PET-CT scans. Initial studies using fully automated approaches to calculate metabolic tumour volume and other PET-based biomarkers have demonstrated appropriate correlation with calculations from experts, warranting further testing in large-scale studies. The extraction of computer-based quantitative tumour characterization through radiomics can provide a comprehensive view of phenotypic heterogeneity that better captures the molecular and functional features of the disease. Additionally, radiomics can be integrated with genomic data to provide more accurate prognostic information. Further improvements in PET-based biomarkers are imminent, although their incorporation into clinical decision-making currently has methodological shortcomings that need to be addressed with confirmatory prospective validation in selected patient populations. In this Review, we discuss the current knowledge, challenges and opportunities in the integration of quantitative PET-based biomarkers in clinical trials and the routine management of patients with lymphoma.

Comparison of first-line treatment with CHOP versus ICED in patients with peripheral T-cell lymphoma eligible for upfront autologous stem cell transplantation

Introduction

Upfront autologous stem cell transplantation (ASCT) has been recommended for patients who are newly diagnosed with peripheral T-cell lymphoma (PTCL), and CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone), an anthracycline-based chemotherapy has been the frontline chemotherapy for PTCL. However, it is not clear whether anthracycline-based chemotherapies such as CHOP could be standard induction therapy for PTCL.

Methods

We conducted a randomized phase II study to compare CHOP with fractionated ifosfamide, carboplatin, etoposide, and dexamethasone (ICED) for patients eligible for ASCT. The primary endpoint was progression-free survival (PFS) and secondary endpoints included objective response rate, overall survival (OS), and safety profiles.

Results

Patients were randomized into either CHOP (n = 69) or ICED (n = 66), and the characteristics of both arms were not different. PTCL-not otherwise specified (NOS, n = 60) and angioimmunoblastic T-cell lymphoma (AITL, n = 53) were dominant. The objective response rate was not different between CHOP (59.4%) and ICED (56.1%), and the 3-year PFS was not different between CHOP (36.7%) and ICED (33.1%). In AITL patients, CHOP was favored over ICED whereas ICED was associated with more cytopenia and reduced dose intensity. Patients who received upfront ASCT after achieving complete response to CHOP or ICED showed 80% of 3-year OS.

Discussion

In summary, our study showed no therapeutic difference between CHOP and ICED in terms of response and PFS. Thus, CHOP might remain the reference regimen especially for AITL based on its better outcome in AITL, and upfront ASCT could be recommended as a consolidation of complete response in patients with PTCL.

PET/CT in Non-Hodgkin Lymphoma: An Update

Non-Hodgkin lymphomas represents a heterogeneous group of lymphoproliferative disorders characterized by different clinical courses, varying from indolent to highly aggressive. ¹⁸F-FDG-PET/CT is the current state-of-the-art diagnostic imaging, for the staging, restaging and evaluation of response to treatment in lymphomas with avidity for ¹⁸F-FDG, despite it is not routinely recommended for surveillance. PET-based response criteria (using five-point Deauville Score) are nowadays uniformly applied in FDG-avid lymphomas. In this review, a comprehensive overview of the role of ¹⁸F-FDG-PET in Non-Hodgkin lymphomas is provided, at each relevant point of patient management, particularly focusing on recent advances on diffuse large B-cell lymphoma and follicular lymphoma, with brief updates also on other histotypes (such as marginal zone, mantle cell, primary mediastinal- B cell lymphoma and T cell lymphoma). PET-derived semiquantitative factors useful for patient stratification and prognostication and emerging radiomics research are also presented.

Molecular Imaging of Lymphoma: Future Directions and Perspectives

More than 250,000 patients die from Hodgkin or non-Hodgkin lymphoma each year. Currently, molecular imaging with ¹⁸F-FDG-PET/CT is the standard of care for lymphoma staging and therapy response assessment. In this review, we will briefly summarize the role of molecular imaging for lymphoma diagnosis, staging, outcome prediction, and prognostication. We discuss future directions in response assessment and surveillance with quantitative PET parameters, the utility of interim assessment, and the differences with response assessment to immunomodulatory therapy. Lastly, we will cover innovations in the field regarding novel tracers and artificial intelligence.

Interim FDG-PET/CT for Response Assessment of Lymphoma

The clinical use and prognostic value of interim FDG-PET/CT (iPET/CT), which is performed after treatment initiation but prior to its completion, varies by lymphoma subtype. Evidence supporting the prognostic value of iPET/CT is more robust for classical Hodgkin lymphoma (cHL), and in this lymphoma subtype, response-adapted treatment approaches guided by iPET/CT are a widely used standard of care for first-line therapy. The data supporting use of iPET/CT among patients with non-Hodgkin lymphoma (NHL) is less well-established, but failure to achieve complete metabolic response on iPET/CT is generally considered a poor prognostic factor with likely consequences for progression free survival. This review will present the available evidence supporting use of iPET/CT in lymphoma patients, particularly as it relates to prognostication and the ability to inform response-adapted treatment strategies. The latter will be addressed through a discussion on the major iPET-response adapted clinical trials with mention of ongoing trials. Special attention will be given to cHL and a few subtypes of NHL, including diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), and peripheral T cell lymphoma (PTCL).

The added prognostic values of baseline PET dissemination parameter in patients with angioimmunoblastic T-cell lymphoma

To explore the prognostic values of baseline 2-deoxy-2-[18F] fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) dissemination parameter in angioimmunoblastic T-cell lymphoma (AITL) and its added values to total metabolic tumour volume (TMTV). Eighty-one AITL patients with at least two FDG-avid lesions in baseline PET/CT were retrospectively included. PET parameters including TMTV and the distance between the two lesions that are the furthest apart (Dmax) were obtained. Univariate Cox analysis showed that both Dmax and TMTV were risk factors for progression-free survival (PFS) and overall survival (OS). Multivariate Cox analysis models of different combinations showed that high Dmax (> 65.7 cm) could independently predict both PFS and OS, while high TMTV (>456.6 cm3) was only significant for OS. A concise PET model based on TMTV and Dmax can effectively risk-stratify patients. PFS and OS rates were significantly lower in patients with high Dmax and high TMTV than in patients with low Dmax and low TMTV (3-year PFS rate: 15.0% vs. 48.7%, p = 0.001; 3-year OS rate: 27.6% vs. 79.0%, p < 0.001). Dmax can directly reflect the disease dissemination characteristic and has a significant prognostic value for FDG-avid AITL patients. It has the potential to be introduced into new risk stratification models for tailored treatment.

Application of the Lugano Classification for Initial Evaluation, Staging, and Response Assessment of Hodgkin and Non-Hodgkin Lymphoma: The PRoLoG Consensus Initiative (Part 1-Clinical)

Our objective was to provide consensus recommendations from a consortium of academic and industry experts in the field of lymphoma and imaging for consistent application of the Lugano classification. Methods: Consensus was obtained through a series of meetings from July 2019 until September 2021 sponsored by the Pharma Imaging Network for Therapeutics and Diagnostics (PINTaD) as part of the PINTaD Response Criteria in Lymphoma Working Group (PRoLoG) consensus initiative. Results: Consensus recommendations clarified technical considerations for PET/CT and diagnostic CT from the Lugano classification, including updating the FDG avidity of different lymphoma entities, clarifying the response nomenclature, and refining lesion classification and scoring, especially with regard to scores 4 and 5 and the X category of the 5-point scale. Combination of metabolic and anatomic responses is clarified, as well as response assessment in cases of discordant or missing evaluations. Use of clinical data in the classification, especially the requirement for bone marrow assessment, is further updated on the basis of lymphoma entities. Clarification is provided with regard to spleen and liver measurements and evaluation, as well as nodal response. Conclusion: Consensus recommendations are made to comprehensively address areas of inconsistency and ambiguity in the classification encountered during response evaluation by end users, and such guidance should be used as a companion to the 2014 Lugano classification.

Management of Peripheral T-cell Lymphomas and the Role of Transplant

PURPOSE OF REVIEW

Here, we review the management of peripheral T-cell lymphoma, particularly focusing on the role of autologous and allogeneic stem cell transplant.

RECENT FINDINGS

Peripheral T-cell lymphomas are a rare subset of non-Hodgkin's lymphomas that are treated with curative intent. While therapy has been based on other aggressive lymphoid malignancies, outcomes are generally poorer than B-cell lymphomas with 5-year overall and progression-free survival of 30-40% and 20-30%, respectively. In effort to improve outcomes, transplant has been used in both the frontline and salvage settings. Although not studied in randomized studies, consolidation with autologous stem cell transplant in first remission has been associated with an approximate 5-year overall survival of 50-60% and 5-year progression-free survival of 40-45%. Unfortunately, most patients relapse, and, in this setting, allogeneic transplant remains the only curative option for those who are transplant-eligible. Multiple series have now shown that 3-year overall survival with allogeneic transplant is approximately 60%. However, outcomes with transplant are associated with disease control at the time of transplant. In contrast to B-cell malignancies, treatment decisions for peripheral T-cell lymphomas are supported mostly by phase II studies, retrospective series, and expert opinion. For patients with peripheral T-cell lymphoma able to achieve sufficient disease control, autologous stem cell transplantation in first remission and allogeneic stem cell transplantation in relapsed disease offer modest benefit over chemotherapy alone.

Prediction of prognosis and pathologic grade in follicular lymphoma using 18F-FDG PET/CT

Purpose

We investigated the utility of a new baseline PET parameter expressing lesion dissemination and metabolic parameters for predicting progression-free survival (PFS) and pathologic grade in follicular lymphoma (FL).

Methods

The baseline ¹⁸F-FDG PET/CT images of 126 patients with grade 1–3A FL were retrospectively analyzed. A novel PET/CT parameter characterizing lesion dissemination, the distance between two lesions that were furthest apart (D_max), was calculated. The total metabolic tumor volume and total lesion glycolysis (TLG) were computed by using 41% of the maximum standardized uptake value (SUV_max) thresholding method.

Results

The 5-year PFS rate was 51.9% for all patients. In the multivariate analysis, high D_max [P = 0.046; hazard ratio (HR) = 2.877], high TLG (P = 0.004; HR = 3.612), and elevated serum lactate dehydrogenase (P = 0.041; HR = 2.287) were independent predictors of PFS. A scoring system for prognostic stratification was established based on these three adverse factors, and the patients were classified into three risk categories: low risk (zero to one factor, n = 75), intermediate risk (two adverse factors, n = 29), and high risk (three adverse factors, n = 22). Patients in the high-risk group had a shorter 3-year PFS (21.7%) than those in the low- and intermediate-risk groups (90.6 and 44.6%, respectively) (P < 0.001). The C-index of our scoring system for PFS (0.785) was superior to the predictive capability of the Follicular Lymphoma International Prognostic Index (FLIPI), FLIPI2, and PRIMA-Prognostic Index (C-index: 0.628–0.701). The receiver operating characteristic curves and decision curve analysis demonstrated that the scoring system had better differentiation and clinical utility than these existing indices. In addition, the median SUV_max was significantly higher in grade 3A (36 cases) than in grades 1 and 2 FL (90 cases) (median: 13.63 vs. 11.45, P = 0.013), but a substantial overlap existed (range: 2.25–39.62 vs. 3.17–39.80).

Conclusion

TLG and D_max represent two complementary aspects of the disease, capturing the tumor burden and lesion dissemination. TLG and D_max are promising metrics for identifying patients at a high risk of progression or relapse. Additionally, SUV_max seems to have some value for distinguishing grade 3A from low-grade FL but cannot substitute for biopsy.

Staging and response assessment of lymphoma: a brief review of the Lugano classification and the role of FDG-PET/CT

The accurate assessment of initial disease status and therapeutic responses is critical to the optimal management of patients with lymphoma. Currently, staging and treatment response evaluation for lymphoma has been standardized into the Lugano classification. Lugano classification incorporates positron emission tomography (PET) into the existing response criteria, and response assessment using FDG-PET/CT has been proven to predict the prognosis in various lymphoma subtypes effectively. We will briefly review the current staging and response evaluation system and explore the role of functional imaging in the field of lymphoma.

T-Cell Lymphomas, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphoproliferative disorders arising from mature T cells, accounting for about 10% of non-Hodgkin lymphomas. PTCL-not otherwise specified is the most common subtype, followed by angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, anaplastic lymphoma kinase-positive, anaplastic large cell lymphoma, anaplastic lymphoma kinase-negative, and enteropathy-associated T-cell lymphoma. This discussion section focuses on the diagnosis and treatment of PTCLs as outlined in the NCCN Guidelines for T-Cell Lymphomas.

Pre-treatment total metabolic tumour volumes in lymphoma: Does quantity matter?

Positron emission tomography/computed tomography (PET/CT) is used for the staging of lymphomas. Clinical information, such as Ann Arbor stage and number of involved sites, is derived from baseline staging and correlates with tumour volume. With modern imaging software, exact measures of total metabolic tumour volumes (tMTV) can be determined, in a semi- or fully-automated manner. Several technical factors, such as tumour segmentation and PET/CT technology influence tMTV and there is no consensus on a standardized uptake value (SUV) thresholding method, or how to include the volumes in the bone marrow and spleen. In diffuse large B-cell lymphoma, follicular lymphoma, peripheral T-cell lymphoma, and Hodgkin lymphoma, tMTV has been shown to predict progression-free survival and/or overall survival, after adjustments for clinical risk scores. However, most studies have used receiver operating curves to determine the optimal cut-off for tMTV and many studies did not include a training-validation approach, which led to the risk of overestimation of the independent prognostic value of tMTV. The identified cut-off values are heterogeneous, even when the same SUV thresholding method is used. Future studies should focus on testing tMTV in homogeneously-treated cohorts and seek to validate identified cut-off values externally so that a prognostic value can be documented, over and above currently used clinical surrogates for tumour volume.

The role of pre-treatment and mid-treatment 18F-FDG PET/CT imaging in evaluating prognosis of peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS)

BACKGROUND

It has been reported the prognostic value of MTV in predicting the disease prognosis of peripheral T-cell lymphoma (PTCL) through pre-treatment PET/CT imaging. However, these are limited data on pretreatment evaluation and prognosis assessments of peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS). This study aimed to determine the prognostic values of pre-treatment and mid-treatment total metabolic tumor volume (MTV), total lesion glycolysis (TLG), and Deauville 5-Point Scale (D-5PS) in accessing the prognosis of PTCL-NOS.

METHODS

A retrospective analysis was conducted in 31 patients with pathologically diagnosed PTCL-NOS. These patients have undergone positron emission PET/CT scanning before and during chemotherapy. Follow-ups were also done to investigate the 2-year progression-free survival (PFS) and Overall Survival (OS) of these patients. During [Formula: see text]F-fluorodeoxyglucose ([Formula: see text]F-FDG) PET/CT scans, the MTV and TLG were recorded. Meanwhile, [Formula: see text]MTV and [Formula: see text]TLG were calculated. Furthermore, the receiver operating characteristic (ROC) curve was employed to classify and to define the threshold values. On the other hand, the mid-chemotherapy assessment and staging of these 31 patients were done by utilizing D-5PS. Subsequently, based on the D-5PS scores obtained, these patients were grouped into two categories: a group of patients with a score of <4 and another group with [Formula: see text]4 points. For these two groups of patients, the survival analysis was done by Kaplan-Meier analysis and a multivariate COX regression model. Moreover, Pearson's chi-square test ([Formula: see text] test) and Spearman rank correlation coefficient were used to comparing the collected data, respectively.

RESULTS

During the 2-year follow-up period, 15 out of the 31 patients experienced disease progression. The optimal threshold values for both baseline MTV and TLG were 158.16 cm[Formula: see text] and 677.40.Additionally, the difference in 2-year PFS between the progressive and non-progressive groups was statistically significant ([Formula: see text], [Formula: see text]; [Formula: see text], [Formula: see text]), significant between-group difference was detected for MTV and for TLG ([Formula: see text], [Formula: see text]; [Formula: see text], [Formula: see text]). On the other hand, when these patients were classified into two groups according to the mid-chemotherapy Deauville score of <4 and [Formula: see text]4, the statistical difference of 2-year PFS between these two groups was significant, too ([Formula: see text], [Formula: see text]),but there is no significant between-group difference in OS ([Formula: see text], [Formula: see text]). COX analysis revealed that D-5PS are the independent factors influencing PFS, while MTV is the independent influencing factor of OS.

CONCLUSION

The baseline total MTV obtained by PET/CT scanning, and D-5PS are crucial prognostic factors in evaluating the prognosis of PTCL-NOS.

Epigenetic focus on angioimmunoblastic T-cell lymphoma: pathogenesis and treatment

PURPOSE OF REVIEW

Angioimmunoblastic T-cell lymphoma (AITL) is a frequent peripheral T-cell lymphoma affecting elderly patients with a poor outcome when treated with conventional chemotherapy. Molecular studies revealed a homogenous mutational landscape gathering anomalies in genes regulating the DNA methylation and hydroxymethylation and anomalies in T-cell signalling.

RECENT FINDINGS

Recent studies indicate that AITL emerges from a TET2 and/or DNMT3A mutated clonal haematopoiesis. This clonal haematopoiesis bearing mutations altering DNA hydroxymethylation can explain the observed coexistence of AITL with myeloid neoplasms. In addition, AITL development requires AITL-specific mutations, such as the RHOAG17V mutations. Combination of TET2 and RHOAG17V alterations results in the development of AITL-like disease in mouse models. The impact of the presence of these mutations on patient outcome seems limited and new biological factor predicting treatment response and survival remains to be determined. At the therapeutic level, therapies targeting epigenetic changes, such as histone deacetylase inhibitors and the hypomethylating 5-azacytidine agent, could have efficacy in this disease and gave promising results. Recent progress in mouse model development should allow development of new treatments.

SUMMARY

Epigenetic changes are frequent in AITL and could be a promising target.

Advances in Frontline Management of Peripheral T-cell Lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphomas that are frequently associated with a poor prognosis. For many decades, the standard-of-care has been CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone)-based therapy, but it is well-recognized that survival outcomes are unsatisfactory, especially when compared with B-cell lymphomas. Major recent advances in cancer diagnosis and management have the potential to significantly improve PTCL outcomes. These include: (1) improved diagnostic techniques that incorporate molecular genetic data to further refine diagnosis and subtyping; (2) the development of novel agents; and (3) improved monitoring modalities, such as ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography scans and circulating tumor DNA. In this review, we aim to explore these 3 advances in the context of frontline management of PTCL.

Prognosis and risk stratification of peripheral T-cell lymphomas

Peripheral T-cell lymphomas represent a rare heterogeneous group of non-Hodgkin lymphomas with generally worse outcomes with standard chemotherapy compared to B-cell lymphomas. Clinical risk prediction tools at baseline have been shown to be prognostic but generally do not impact clinical decision making. However, improving understanding of the prognostic implications of histology and its molecular underpinnings as well as strategies surrounding the use of CD30 as a predictive biomarker for brentuximab vedotin have led to better understanding of how to risk stratify patients. Baseline, interim, and end of treatment PET/CT as evaluated by the Lugano criteria as well as by baseline metabolic tumor volume have also been shown to be prognostic. The role of minimal residual disease tools such as cell free DNA and T-cell gene receptor sequencing remain active areas of investigation in hopes to develop predictive biomarkers in these rare diseases. This review focuses on strategies used to prognosticate in more common forms of peripheral T-cell lymphoma as well as in extranodal NK/T-cell lymphoma.

Integrative analysis of a phase 2 trial combining lenalidomide with CHOP in angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is a frequent T-cell lymphoma in the elderly population that has a poor prognosis when treated with cyclophosphamide, doxorubicin, vincristine, and prednisone  (CHOP) therapy. Lenalidomide, which has been safely combined with CHOP to treat B-cell lymphoma, has shown efficacy as a single agent in AITL treatment. We performed a multicentric phase 2 trial combining 25 mg lenalidomide daily for 14 days per cycle with 8 cycles of CHOP21 in previously untreated AITL patients aged 60 to 80 years. The primary objective was the complete metabolic response (CMR) rate at the end of treatment. Seventy-eight of the 80 patients enrolled were included in the efficacy and safety analysis. CMR was achieved in 32 (41%; 95% confidence interval [CI], 30%-52.7%) patients, which was below the prespecified CMR rate of 55% defined as success in the study. The 2-year progression-free survival (PFS) was 42.1% (95% CI, 30.9%-52.8%), and the 2-year overall survival was 59.2% (95% CI, 47.3%-69.3%). The most common toxicities were hematologic and led to treatment discontinuation in 15% of patients. This large prospective and uniform series of AITL treatment data was used to perform an integrative analysis of clinical, pathologic, biologic, and molecular data. TET2, RHOA, DNMT3A, and IDH2 mutations were present in 78%, 54%, 32%, and 22% of patients, respectively. IDH2 mutations were associated with distinct pathologic and clinical features and DNMT3A was associated with shorter PFS. In conclusion, the combination of lenalidomide and CHOP did not improve the CMR in AITL patients. This trial clarified the clinical impact of recurrent mutations in AITL. This trial was registered at www.clincialtrials.gov as #NCT01553786.

Baseline total metabolic tumor volume combined with international peripheral T-cell lymphoma project may improve prognostic stratification for patients with peripheral T-cell lymphoma (PTCL)

Purpose

The aim of this study was to explore the prognostic value of total metabolic tumor volume (TMTV) at baseline ¹⁸F-FDG PET/CT in patients diagnosed with peripheral T-cell lymphoma (PTCL).

Materials and methods

Eighty-four newly diagnosed PTCL patients who underwent baseline ¹⁸F-FDG PET/CT prior to treatment between March 2009 and January 2019 were enrolled in this retrospective study. The FDG-avid lesions in each patient were segmented using semiautomated software to calculate the maximum standardized uptake value (SUVmax), total metabolic tumor volume (TMTV), and total lesion glycolysis (TLG) values using the boundaries of voxels presenting with the 41% SUVmax threshold method. Progression-free survival (PFS) and overall survival (OS) were used as end points to evaluate patient prognosis. The log-rank test and Cox regression analyses were used to evaluate PFS and OS.

Results

ROC curve analysis indicated an ideal TMTV cut-off value of 228.8 cm³. During the 4–131 months (29.2 ± 28.5 months) follow-up period, high TMTV was significantly associated with worse PFS and OS. TMTV and the international peripheral T-cell lymphoma project score (IPTCLP) were independent predictors of PFS and OS with multivariate analysis. The combination of TMTV and the IPTCLP may provide significantly better risk substratification in PFS and OS of PTCL patients.

Conclusions

Both TMTV and IPTCLP are independent predictors of PTCL patient survival outcomes. Moreover, the combination of TMTV and IPTCLP improved patient risk stratification and may contribute to personalized therapeutic regimens.

Baseline total lesion glycolysis combined with interim positron emission tomography-computed tomography is a robust predictor of outcome in patients with peripheral T-cell lymphoma

BACKGROUND

Peripheral T-cell lymphoma (PTCL) represents a heterogeneous and rare subgroup of aggressive lymphomas that generally demonstrate poor clinical outcomes with conventional treatment. Since the prognosis of PTCL is heterogeneous, more accurate risk assessment, and risk-adapted treatment strategies are required. In this study, we examined whether interim positron emission tomography (iPET)-computed tomography (PET/CT) results can be combined with baseline volume-based metabolic assessments including total metabolic tumor volume (TMTV) and total lesion glycolysis (TLG) for risk stratification in PTCL.

METHODS

The data of 63 patients with nodal PTCL, who had analyzable baseline PET/CT and iPET, were retrospectively reviewed. We calculated the baseline TMTV and TLG values. All iPET responses were analyzed using the Deauville 5-point scale.

RESULTS

On univariate analysis, a prognostic index for PTCL (PIT) higher than 2 (hazard ratio [HR], 2.03; P = .026), high TMTV (>389 cm³ ; HR, 2.24; P = .01), high TLG (>875; HR, 3.77; P = .0005), and positive iPET (HR, 2.18; P = .009) were significantly associated with poorer progression-free survival (PFS). On multivariate analysis, only high TLG and positive iPET independently predicted both poorer overall survival (OS) and PFS. A model combining TLG and iPET showed that patients with low TLG and negative iPET had superior outcomes, with a 5-year PFS and OS of 72% and 90%, respectively. Conversely, both 5-year PFS and OS for those with high TLG and positive iPET were 0%.

CONCLUSIONS

In summary, TLG combined with iPET predicted survival in PTCL more accurately. This information may help in the development of risk-adapted treatment strategies for PTCL.

Rituximab Plus Chemotherapy Provides No Clinical Benefit in a Peripheral T-Cell Lymphoma Not Otherwise Specified with Aberrant Expression of CD20 and CD79a: A Case Report and Review of the Literature

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is the most common entity of mature T-cell neoplasms. PTCL-NOS generally has an aggressive behavior and is often refractory to standard therapy. Only a few cases of PTCL with aberrant expression of B-cell antigens have been reported so far. This phenotypic aberrancy may lead to misdiagnosis as B-cell non-Hodgkin lymphomas and eventual inappropriate patient management, whereas in an accurately diagnosed PTCL, the presence of CD20 may appear as an appealing therapeutic target. In this setting, response to anti-CD20 monoclonal antibody in combination with chemotherapy has been poorly explored. We describe the case of a 59-year-old male diagnosed by a pathological and molecular approach as PTCL-NOS with aberrant co-expression of the B-cell antigens CD20 and CD79a, which proved non-responsive to the addition of rituximab to standard polychemotherapy. This case highlights that the presence of CD20 in PTCL may be misleading in the diagnosis and also act as a lure for the clinician to adopt a rituximab-based treatment, the effectiveness of which is undefined as the molecular mechanisms underlying B-cell marker expression in PTCL.

Prognostic Values of Baseline 18F-FDG PET/CT in Patients with Peripheral T-Cell Lymphoma

Purpose

In the present study, we aimed to investigate whether the metabolic parameters on baseline ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) could be used to predict prognosis in peripheral T-cell lymphomas (PTCL).

Methods

A total of 51 nodal PTCL patients who underwent baseline ¹⁸F-FDG PET/CT were retrospectively evaluated in the present study. Total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUV_max) were also assessed. Besides, the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) was also included. Log-rank test and Cox regression analysis were used to evaluate progression-free survival (PFS) and overall survival (OS).

Results

The median follow-up was 18 months. Patients with low TLG, TMTV, and SUV_max levels had a significantly better clinical outcome than those with high TLG, TMTV, and SUV_max levels. The 2-year PFS rates of the high- and low-TMTV groups were 34.62% and 80%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (n = 10), intermediate-risk group with TMTV > 62.405 or NCCN-IPI score of 4-8 (2-year PFS and OS were 52.4% and 66.7%, respectively, n = 10), intermediate-risk group with TMTV > 62.405 or NCCN-IPI score of 4-8 (2-year PFS and OS were 52.4% and 66.7%, respectively, n = 10), intermediate-risk group with TMTV > 62.405 or NCCN-IPI score of 4-8 (2-year PFS and OS were 52.4% and 66.7%, respectively,

Conclusions

Baseline TMTV and TLG were independent predictors of PFS and OS in PTCL patients, and SUV_max and NCCN-IPI scores were also independent predictors of OS. Moreover, the combination of TMTV and NCCN-IPI scores improved patient risk-stratification at the initial stage and might contribute to the adjustment of the therapeutic regime. This trial is registered with ChiCTR1900025526.

Baseline and interim PET-based outcome prediction in peripheral T-cell lymphoma: A subgroup analysis of the PETAL trial

The prospective randomized Positron Emission Tomography (PET)-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial was designed to test the ability of interim PET (iPET) to direct therapy. As reported previously, outcome remained unaffected by iPET-based treatment changes. In this subgroup analysis, we studied the prognostic value of baseline total metabolic tumor volume (TMTV) and iPET response in 76 patients with T-cell lymphoma. TMTV was measured using the 41% maximum standardized uptake value (SUV_41max ) and SUV₄ thresholding methods. Interim PET was performed after two treatment cycles and evaluated using the ΔSUV_max approach and the Deauville scale. Because of significant differences in outcome, patients with anaplastic lymphoma kinase (ALK)-positive lymphoma were analyzed separately from patients with ALK-negative lymphoma. In the latter, TMTV was statistically significantly correlated with progression-free survival, with thresholds best dichotomizing the population, of 232 cm³ using SUV_41max and 460 cm³ using SUV₄ . For iPET response, the respective thresholds were 46.9% SUV_max reduction and Deauville score 1-4 vs 5. The proportion of poor prognosis patients was 46% and 29% for TMTV by SUV_41max and SUV₄ , and 29% and 25% for iPET response by ΔSUV_max and Deauville, respectively. At diagnosis, the hazard ratio (95% confidence interval) for poor prognosis vs good prognosis patients according to TMTV was 2.291 (1.135-4.624) for SUV_41max and 3.206 (1.524-6.743) for SUV₄ . At iPET, it was 3.910 (1.891-8.087) for ΔSUV_max and 4.371 (2.079-9.187) for Deauville. On multivariable analysis, only TMTV and iPET response independently predicted survival. Patients with high baseline TMTV and poor iPET response (22% of the population) invariably progressed or died within the first year (hazard ratio, 9.031 [3.651-22.336]). Due to small numbers and events, PET did not predict survival in ALK-positive lymphoma. Baseline TMTV and iPET response are promising tools to select patients with ALK-negative T-cell lymphoma for early allogeneic transplantation or innovative therapies.

The new biology of PTCL-NOS and AITL: current status and future clinical impact

Peripheral T-cell lymphomas (PTCL) comprise a heterogeneous group of aggressive lymphoproliferative disorders almost all of which are associated with poor clinical outcomes. Angioimmunoblastic T-cell lymphoma (AITL) and some peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) have similarities to normal CD4⁺ T-cell subsets in their gene expression profiles. A cell of origin model is, therefore, emerging and is likely to be refined in the future. Follicular helper (Tfh) T cells are now established as the cell of origin of AITL and about 20% of PTCL-NOS. Sequencing studies have identified recurrent genetic alterations in epigenetic modifiers, T-cell receptor signalling pathway intermediates or RHOA, most commonly a specific mutation leading to RHOA G17V. While PTCL-NOS remains a diagnosis of exclusion, advances in genomics have identified subgroups expressing transcription factors TBX 21 (Th1-like origin) and GATA3 (Th2-like origin). These findings suggest new biomarkers and new therapeutic avenues including the hypomethylating agent azacytidine, or inhibitors of proximal T-cell receptor (TCR) signalling and potentially certain monoclonal antibodies. The advances over the past few years, therefore, prompt stratified medicine approaches to test biologically based treatments and determine the clinical utility of the new disease classifications.

Emerging strategies in peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogenous group of aggressive non-Hodgkin lymphomas that are less chemosensitive than their B-cell counterparts. Until recently, standard therapy did not distinguish between subtypes, and deeper understanding of the biology of these diseases was lacking. The availability of targeted therapy and more sophisticated subtype classification has translated into the development of novel treatment options for these rare diseases. This includes the development of a brentuximab vedotin-based upfront chemotherapy regimen that confers an overall survival benefit for a subset of patients. Clinical trials of targeted agents, as well as development of better preclinical models of PTCL, are leading to therapeutic advances in the field, including the development of phosphoinositide-3-kinase inhibitors, histone deacetylase inhibitor-based strategies, CD30-directed strategies, Janus kinase inhibitors, and spleen-associated tyrosine kinase inhibitors. Better understanding of the biology of these diseases based on gene expression profiling, minimal residual disease evaluation, and modeling in patient-derived xenografts should help define mechanisms of response and resistance to therapy. Given the complex biology of these heterogeneous lymphomas, well-tolerated combination strategies targeted toward specific subtypes of PTCL can lead to advances in the field. Similar to the story of brentuximab vedotin, development of effective therapies in the salvage setting will likely lead to improved upfront strategies in PTCLs, and ultimately a more personalized approach.

Event free survival at 24 months is a strong surrogate prognostic endpoint of peripheral T cell lymphoma

Event free survival at 24 months (EFS24) has been described as a powerful predictor for outcome in several subtypes of B cell lymphoma. However, it was limitedly described in T cell lymphoma. We explored the implication of EFS24 as a predictor marker for peripheral T cell lymphoma (PTCL). We reviewed 293 systemic PTCL patients at 13 nationwide major university hospitals in Thailand from 2007 to 2014. The median event free survival (EFS) and overall survival (OS) of PTCL patients in our cohort was 16.3 and 27.7 months with corresponding 2-year EFS and 2-year OS of 45.8% and 51.9%, respectively. A total of 118 patients achieved EFS24 (no events during the first 24 mo). Patients who achieved EFS24 had better OS than patients who did not (2-y OS 92% vs 18.8%; HR, 0.1; P < .001). The standardized mortality ratio of patients achieving EFS24 was 18.7 (95% CI, 14.6-22.8). Multivariable analysis demonstrated performance status, histologic subtype, remission status, and EFS24 achievement as independent predictors for OS. Our study affirmed the value of EFS24 as a powerful prognostic factor for PTCL. Further validation in prospective study setting is warranted.

Prognostic values of baseline, interim and end-of therapy 18F-FDG PET/CT in patients with follicular lymphoma

Purpose

In the present study, we aimed to investigate the role of baseline, interim and end-of treatment positron emission tomography/computed tomography (PET/CT) in assessing the prognosis of follicular lymphoma (FL).

Methods

A total of 84 FL patients were retrospectively analyzed in this study. Baseline (n=59), interim (n=24, after 2–4 cycles) and end-of treatment (n=43) PET/CT images were re-evaluated, and baseline maximum standardized uptake value (SUV_max), total metabolic tumor volume (tMTV) and total lesion glycolysis (TLG) were recorded. Interim (I-PET) and end-of treatment (E-PET) PET/CT responses were interpreted by Deauville five-point scale (D-5PS) and International Harmonization Project criteria (IHP). Survival curves were calculated by Kaplan-Meier curves, and differences between groups were compared by log-rank test.

Results

The 2-year progression-free survival (PFS) of the high- and low-TLG groups was 57.14% and 95.56%, respectively (p=0.0001). The 2-year overall survival (OS) of the high- and low-TLG groups was 62.50% and 100%, respectively (p<0.0001). Multivariate analysis showed that TLG was an independent prognostic factor for PFS (p=0.001, HR=6.577, 95% CI=2.167–19.960) and OS (p=0.030, HR=19.291, 95% CI =2.689–137.947). Besides, Eastern Cooperative Oncology Group (ECOG) was the independent prognostic factor for OS (HR=8.924, 95% CI=1.273–62.559, p=0.028). Interim PET results based on D-5PS or IHP criteria were not significantly correlated with PFS (all p>0.05). However, E-PET results using D-5PS and IHP criteria were statistically significant (p=0.0001 and p=0.006). The D-5PS showed stronger prognostic value compared with IHP criteria. The optimal cutoff value of ΔSUV_max% was 66.95% according to I-PET and 68.97% according to E-PET. However, only the ΔSUV_max% from the baseline to the end-of therapy yielded statistically significant results in the prediction of PFS (p=0.0002).

Conclusion

Our findings indicated that the baseline TLG and E-PET results were significantly associated with prognosis in patients with FL.