PET-adapted approaches to primary therapy for advanced Hodgkin lymphoma

Recent advancements in 18F-FDG PET/CT for the diagnosis, staging, and treatment management of HIV-related lymphoma

Infection with the Human Immunodeficiency Virus (HIV) is one of the most pressing issues facing public health on a worldwide scale. Currently, HIV-related lymphoma is the most common cause of death among people living with HIV, and warrants more attention. The unique challenges associated with HIV-related lymphoma management derive from the underlying HIV infection and its immunosuppressive effects. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has gained significant prominence in the past few years as a valuable diagnostic and therapeutic instrument for the treatment of HIV-related lymphoma. This review will start with an overview of the subtypes, risk factors, and therapeutic choices for individuals with HIV-related lymphoma. We will then briefly discuss the current application of 18F-FDG PET/CT in the medical management of HIV-related lymphoma patients, followed by the initial staging of the disease, the evaluation of therapeutic response, the prediction of prognostic outcomes, the decision-making process for radiotherapy guided by PET findings, and the distinguishing of various diagnoses.

Immune checkpoint inhibitors in advanced and relapsed/refractory Hodgkin lymphoma: current applications and future prospects

Classic Hodgkin lymphoma (cHL) treatment paradigms are undergoing a shift with the integration of immune checkpoint inhibitors (ICIs) into both first-line and relapsed/refractory (R/R) regimens. In first-line therapy, the synergy between ICIs and chemotherapy may surpass the previous standards of ABVD and BV-AVD established by landmark trials including RATHL and ECHELON-1. In R/R disease, the combination of ICIs with chemotherapy has begun to challenge the paradigm of chemotherapy as a bridge to consolidative autologous stem cell transplantation. The clinical advances heralded by ICI offer unique challenges to management. ICI treatment and the associated inflammatory response can make the traditional timing and modalities of treatment response assessment difficult to interpret. In contrast to ABVD and BV-AVD, pembrolizumab-AVD results in PET2 positivity rates that are higher and less predictive of treatment response even when ultimate outcomes may be superior. This suggests that the predictive value of PET2 may be less reliable in the ICI era, prompting a reevaluation of response assessment strategies. Looking forward, circulating tumor DNA (ctDNA) may be a promising tool in response-adapted therapy. Its potential to complement or even supersede PET scans in predicting response to ICIs represents a critical advancement. The integration of ctDNA analysis holds the promise of refining response-adapted approaches and enhancing precision in therapeutic decision-making for patients with cHL. This review navigates the evolving landscape of cHL therapy, emphasizing the paradigmatic shift brought about by ICIs. This article explores the impact of combining ICIs with chemotherapy in both relapsed/refractory and first-line settings, scrutinizes the challenges posed to response-adapted therapy by ICIs, and highlights the potential role of ctDNA as an adjunct in refining response-adapted strategies for cHL.

Cost-effectiveness of response-adapted therapy (RAT) for advanced Hodgkin's Lymphoma compared with conventional treatment in India: a Markov-model based analysis

Cost effectiveness analysis of interim positron emission tomography (PET-2, done after 2 cycles of chemotherapy) based response adaptive therapy (RAT) approaches in advanced Hodgkin lymphoma (aHL) are not available from an Indian perspective. We used a five-year decision analytics model to assess the cost-effectiveness of the two RAT approaches [(escalation (RAT-1) or de-escalation (RAT-2)] compared with standard care (SOC) in aHL (mean age:35 years). Modelling data was derived from secondary sources and sensitivity analyses were performed to assess the robustness of the model. Net monetary benefit (NMB) gained from RAT2 in Indian rupees (INR) (INR 2,26,896) was higher than the RAT1 (INR 1,83,138) when compared with SOC. Proportion achieving the complete response after initial treatment (CR1) was the key determining factor for the RAT1/2 dominance over SOC. Despite higher initial input costs, response-adapted therapy of aHL was cost-effective by minimizing the cost incurred and disutility experienced during relapse and salvage.

Response-Adapted Therapy for Newly Diagnosed Multiple Myeloma

PURPOSE OF REVIEW

The development of potent novel agents has improved outcomes for patients with multiple myeloma (MM). Heterogeneity of response to therapy, an expanding arsenal of treatment options, and cost are however major challenges for physicians making treatment decisions. Response-adapted therapy is hence an attractive strategy for sequencing of therapy in MM. Despite its successful application in other haematologic malignancies, response-adapted therapy is yet to become a standard of care for MM. We provide our perspective on response-adapted therapeutic strategies evaluated thus far and how they may be implemented and improved on in treatment algorithms of the future.

RECENT FINDINGS

While older studies suggested that early response based on International Myeloma Working Group response criteria could impact long-term outcomes, recent data have contradicted these findings. The advent of minimal residual disease (MRD) as a powerful prognostic factor in MM has raised the promise of MRD-adapted treatment strategies. The development of more sensitive techniques for paraprotein quantification as well as imaging modalities to detect extramedullary disease is likely to change response assessment in MM. These techniques combined with MRD assessment may provide sensitive and holistic response assessments which could be evaluated in clinical trials. Response-adapted treatment algorithms have the potential to allow an individualised treatment strategy, maximising efficacy, while minimising toxicities and cost. Standardisation of MRD methodology, incorporation of imaging into response assessment, and the optimal management of MRD positive patients are key questions to be addressed in future trials.

Clinical value of 18F-FDG PET/CT in the management of HIV-associated lymphoma

HIV is still a major public health problem. At present, HIV-associated lymphoma remains the leading cause of deaths among people living with HIV, which should be paid more attention to. ¹⁸F-fluorodeoxglucose (FDG) PET/CT has been recommended in the initial staging, restaging, response assessment and prognostic prediction of lymphomas in general population. HIV-associated lymphoma is, however, a different entity from lymphoma in HIV-negative with a poorer prognosis. The ability to accurately risk-stratify HIV-infected patients with lymphoma will help guide treatment strategy and improve the prognosis. In the review, the current clinical applications of ¹⁸F-FDG PET/CT in HIV-associated lymphoma will be discussed, such as diagnosis, initial staging, response evaluation, prognostic prediction, PET-guided radiotherapy decision, and surveillance for recurrence. Moreover, future perspectives will also be presented.

PET-CT in Clinical Adult Oncology: I. Hematologic Malignancies

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging and evaluation of suspected recurrence. The goal of this 6-part series of review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for the more common adult malignancies. In the first article of this series, hematologic malignancies are addressed. The classification of these malignancies will be outlined, with the disclaimer that the classification of lymphomas is constantly evolving. Critical applications, potential pitfalls, and nuances of PET-CT imaging in hematologic malignancies and imaging features of the major categories of these tumors are addressed. Issues of clinical importance that must be reported by the imaging professionals are outlined. The focus of this article is on [¹⁸F] fluorodeoxyglucose (FDG), rather that research tracers or those requiring a local cyclotron. This information will serve as a resource for the appropriate role and limitations of PET-CT in the clinical management of patients with hematological malignancy for health care professionals caring for adult patients with hematologic malignancies. It also serves as a practical guide for imaging providers, including radiologists, nuclear medicine physicians and their trainees.

Minimising the Toxicities of First Line Hodgkin Lymphoma Treatment in the Modern Era

Striking advances in the treatment of Hodgkin lymphoma over the last 30 years have culminated in high rates of disease-free survival in younger patients with early and advanced stage disease. In this review we focus on strategies that have evolved over recent years to reduce short and long-term toxicities of treatment. These strategies include the selection of first-line chemotherapy, the stratification of patients based on initial response and subsequent adaptation of treatment, the addition of novel agents (e.g., brentuximab vedotin), the removal of specific drugs (e.g., bleomycin), the use of drug substitution, and the removal of consolidation radiotherapy based on interim and end of treatment PET assessment. While these strategies have successfully reduced toxicity of Hodgkin lymphoma therapy, the cornerstone of treatment continues to be combination chemotherapy and radiotherapy with significant short- and long-term side effects. To further reduce toxicity while maintaining or improving efficacy, we shall need to incorporate novel agents into our first-line treatment algorithms, and several such potentially practice-changing trials are underway.

Utility of pre-treatment FDG PET/CT-derived machine learning models for outcome prediction in classical Hodgkin lymphoma

Objectives

Relapse occurs in ~20% of patients with classical Hodgkin lymphoma (cHL) despite treatment adaption based on 2-deoxy-2-[¹⁸F]fluoro-d-glucose positron emission tomography/computed tomography response. The objective was to evaluate pre-treatment FDG PET/CT–derived machine learning (ML) models for predicting outcome in patients with cHL.

Methods

All cHL patients undergoing pre-treatment PET/CT at our institution between 2008 and 2018 were retrospectively identified. A 1.5 × mean liver standardised uptake value (SUV) and a fixed 4.0 SUV threshold were used to segment PET/CT data. Feature extraction was performed using PyRadiomics with ComBat harmonisation. Training (80%) and test (20%) cohorts stratified around 2-year event-free survival (EFS), age, sex, ethnicity and disease stage were defined. Seven ML models were trained and hyperparameters tuned using stratified 5-fold cross-validation. Area under the curve (AUC) from receiver operator characteristic analysis was used to assess performance.

Results

A total of 289 patients (153 males), median age 36 (range 16–88 years), were included. There was no significant difference between training (n = 231) and test cohorts (n = 58) (p value > 0.05). A ridge regression model using a 1.5 × mean liver SUV segmentation had the highest performance, with mean training, validation and test AUCs of 0.82 ± 0.002, 0.79 ± 0.01 and 0.81 ± 0.12. However, there was no significant difference between a logistic model derived from metabolic tumour volume and clinical features or the highest performing radiomic model.

Conclusions

Outcome prediction using pre-treatment FDG PET/CT–derived ML models is feasible in cHL patients. Further work is needed to determine optimum predictive thresholds for clinical use.

Key points

• A fixed threshold segmentation method led to more robust radiomic features.

• A radiomic-based model for predicting 2-year event-free survival in classical Hodgkin lymphoma patients is feasible.

• A predictive model based on ridge regression was the best performing model on our dataset.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-022-09039-0.

Evolving management strategies for lymphomas during the COVID-19 pandemic

The evolving CoViD-19 pandemic has raised unprecedented challenges for physicians who face significant constraints in medical resources and cancer therapies. The management of patients with lymphoma represents a unique challenge given the heterogeneity of the patient population and treatment goals as well as the myriad choices of therapy available to clinicians. Adaptation in clinical practice with the goal of maintaining appropriate continuity and quality of care while mitigating exposure risk has forced clinicians around the world to develop new standards of practice and can pose difficult ethical choices in vulnerable patient populations. Based on recommendations formulated by several medical groups and societies, this article provides an overview of the general and specific practical considerations that apply to the care of lymphoma patients during the outbreak. We hope to provide a practical framework to help guide physicians in their therapeutic choices and facilitate the ongoing management of this specific patient population.