Interim FDG18-PET SUVmax Variation Adds Prognostic Value to Deauville 5-Point Scale in the Identification of Patients with Ultra-High-Risk Diffuse Large B Cell Lymphoma

Primary mediastinal B-cell lymphoma (PMBCL): The LYSA pragmatic guidelines

Primary mediastinal B-cell lymphoma (PMBCL) is a distinct subtype of large B-cell lymphoma with unique clinical, histopathological, and molecular characteristics. Despite its aggressive nature, PMBCL has a high cure rate when managed appropriately. Advances in the understanding of PMBCL biological characteristics, coupled with improvements in diagnostic tools and therapeutic approaches, have significantly improved patient outcomes in recent years. In this article, we present a set of pragmatic guidelines developed by the Lymphoma Study Association (LYSA) for the management of PMBCL. These guidelines address key aspects of diagnosis, staging, response evaluation, and treatment, integrating the latest evidence from clinical trials, expert consensus, and real-world practice. The aim of the guidelines is to provide clinicians with a clear, practical framework to optimize care for patients with PMBCL, ensuring that the best available evidence is translated into clinical practice.

Prognostic role of interim PET-CT demonstrating partial metabolic response in diffuse large B-Cell lymphoma: a retrospective study

OBJECTIVE

Interim 18F-FDG PET/CT (iPET/CT) imaging demonstrates potential in assessing the early therapeutic response in lymphoma. Nevertheless, the prognostic significance of interim PET-CT in diffuse large B-cell lymphoma (DLBCL) remains controversial. This study aimed to evaluate whether semi-quantitative PET/CT metabolic parameters and other metrics could enhance the prognostic value of interim PET/CT in DLBCL patients exhibiting partial metabolic remission (PMR).

METHODS

A retrospective analysis was performed from January 2018 to December 2023, focusing on patients with DLBCL who achieved PMR on interim PET-CT. Patient demographics, clinical characteristics, and semi-quantitative PET/CT metabolic parameters were extracted from the medical records. Multivariate analyses were conducted to identify the risk factors associated with failure to achieve complete metabolic remission (CMR) at the end of treatment (EOT). Receiver operating characteristic (ROC) curve analysis was employed to determine the optimal cut-off values for continuous predictive variables. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier methods, and risk factors were evaluated using Cox regression models.

RESULTS

In a cohort consisting of 80 newly diagnosed DLBCL cases that exhibited PMR on interim PET scans, 50 cases ultimately achieved CMR, while the remaining 30 cases still had positive PET findings at EOT. Analysis revealed that the interim lesion-to-liver maximum standardized uptake value ratio (RLL) and bone marrow involvement were independent prognostic factors for positive PET-CT outcomes at EOT. Notably, an interim RLL threshold greater than 1.66 emerged as a reliable predictor with a sensitivity of 73.3% and a specificity of 72.0%. Additionally, the International Prognostic Index (IPI) and interim RLL were identified as independent prognostic indicators for both progression-free survival (PFS) and overall survival (OS).

CONCLUSION

Our study revealed that within the cohort of DLBCL patients exhibiting PMR on interim PET scans, an interim RLL greater than 1.66 and bone marrow involvement emerged as independent risk factors for positive PET results at the end of treatment. Additionally, the IPI and interim RLL were identified as independent prognostic markers for both progression-free survival and overall survival. The integration of clinical characteristics with semi-quantitative PET/CT parameters has the potential to enhance the prognostic role of interim PET/CT exhibiting PMR in DLBCL cases.

2-deoxy-2-[18F]FDG PET Imaging for Therapy Assessment in Hodgkin's and Non-Hodgkin Lymphomas

The 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography combined with computed tomography (PET/CT) has contributed to outcome improvement of patients with lymphoma. The use of [18F]FDG PET/CT for staging and response assessment is successfully applied both in routine clinical practice and in clinical trials. The challenges lie in enhancing the outcomes of lymphoma patients, particularly those with advanced or refractory/relapsed disease, and to minimize the long-term toxicity associated with treatments, including radiation therapy. The objective of this review article is to present contemporary data on the use of [18F]FDG PET/CT for treatment assessment of aggressive lymphomas.

Evaluation of therapeutic effect and prognostic value of 18F-FDG PET/CT in different treatment nodes of DLBCL patients

BACKGROUND

In the present study, we aimed to investigate the role of baseline (B), interim (I) and end-of-treatment (Eot) 18F-FDG PET/CT in assessing the prognosis of diffuse large B cell lymphoma (DLBCL), so as to identify patients who need intensive treatment at an early stage.

METHODS

A total of 127 DLBCL patients (62 men; 65 women; median age 62 years) were retrospectively analyzed in this study. Baseline (n = 127), interim (n = 127, after 3-4 cycles) and end-of-treatment (n = 53, after 6-8 cycles) PET/CT images were re-evaluated; semi-quantitative parameters such as maximum standardized uptake value of lesion-to-liver ratio (SUVmax(LLR)) and lesion-to-mediastinum ratio (SUVmax(LMR)), total metabolic tumor volume (TMTV) and total metabolic tumor volume (TLG) were recorded. ΔTLG1 was the change of interim relative to baseline TLG (I to B), ΔTLG2 (Eot to B). ΔSUVmax and ΔTMTV were the same algorithm. The visual Deauville 5-point scale (D-5PS) has been adopted as the major criterion for PET evaluation. Visual analysis (VA) and semi-quantitative parameters were assessed for the ability to predict progression-free survival (PFS) and overall survival (OS) by using Kaplan-Meier method, cox regression and logistic regression analysis. When visual and semi-quantitative analysis are combined, the result is only positive if both are positive.

RESULTS

At a median follow-up of 34 months, the median PFS and OS were 20 and 32 months. The survival curve analysis showed that advanced stage and IPI score with poor prognosis, ΔSUVmax(LLR)1 < 89.2%, ΔTMTV1 < 91.8% and ΔTLG1 < 98.8%, ΔSUVmax(LLR)2 < 86.4% were significantly related to the shortening of PFS in patient (p < 0.05). ΔSUVmax(LLR)1 < 83.2% and ΔTLG1 < 97.6% were significantly correlated with the shortening of OS in patients (p < 0.05). Visual analysis showed that incomplete metabolic remission at I-PET and Eot-PET increased the risk of progress and death. In terms of predicting recurrence by I-PET, the combination of visual and semi-quantitative parameters showed higher positive predictive value (PPV) and specificity than a single index.

CONCLUSION

Three to four cycles of R-CHOP treatment may be a time point for early prediction of early recurrence/refractory (R/R) patients and active preemptive treatment. Combined visual analysis with semi-quantitative parameters of 18F-FDG PET/CT at interim can improve prognostic accuracy and may allow for more precise screening of patients requiring early intensive therapy.

Integration of PET in DLBCL

F-fluorodeoxyglucose positron emission tomography-computerized tomography (18FDG-PET/CT) is the gold-standard imaging modality for staging and response assessment for most lymphomas. This review focuses on the utility of 18FDG-PET/CT, and its role in staging, prognostication and response assessment in diffuse large B-cell lymphoma (DLBCL), including emerging possibilities for future use.