Use of positron emission tomography for response assessment of lymphoma: consensus of the Imaging Subcommittee of International Harmonization Project in Lymphoma

Maximum tumor diameter is associated with relapse risk in limited-stage Hodgkin lymphoma: an international study

ABSTRACT

Tumor bulk is an established prognostic factor in Hodgkin lymphoma (HL), but most patients with limited-stage (LS) HL do not have "bulk" by standard definitions. In the RAPID trial, maximum tumor diameter (MTD) was associated with relapse risk in LS-HL patients achieving positron emission tomography negativity (PET-) after doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). We aimed to externally validate these findings in the H10 trial. Stage I/IIA HL patients, without mediastinal bulk, who achieved PET- with ABVD were included. Patients received 3 ABVD plus radiotherapy (n = 208) or 3 ABVD alone (n = 211) in RAPID, and 3 to 4 ABVD plus radiotherapy (n = 556) or 4 to 6 ABVD alone (n = 303) in H10. MTD was strongly associated with event-free survival (relapse or HL-related death) in H10 (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.07-1.38; P = .003), a similar effect to that seen in RAPID (HR, 1.19; 95% CI, 1.02-1.39; P = .02), giving an estimated 21% risk increase per centimeter MTD (HRpooled, 1.21; 95% CI, 1.09-1.33; P < .001). Effect sizes were similar for patients treated with ABVD alone and ABVD plus radiotherapy, with no differential effect (pinteraction = 0.97). Treatment modality and MTD were independent risk factors; patients with higher MTD receiving chemotherapy alone had the greatest relapse risk. This international validation study confirms MTD is strongly associated with relapse risk in patients with LS-HL achieving PET- and informs decision-making around risk-adapted application of radiotherapy. The trials were registered at www.clinicaltrials.gov as #NCT00943423 and #NCT00433433.

Development and validation of novel models based on clonality immunoglobulin gene rearrangement for evaluation of bone marrow involvement and prognostic prediction in patients with diffuse large B-cell Lymphoma: a multicenter retrospective study

Introduction

Bone marrow involvement (BMI) is a poor prognostic factor in diffuse large B cell lymphoma (DLBCL), and accurate evaluation of BMI is crucial for determining stages and prognosis. This study aimed to identify the most effective examinations for evaluating BMI in DLBCL, including positron emission tomography-computed tomography (PET/CT), immunoglobulin gene rearrangement (IGR), flow cytometry (FCM), bone marrow cytology (BMC) and bone marrow biopsy pathology (BMB), and to further explore its prognostic significance in DLBCL patients.

Methods

This retrospective study included 364 newly diagnosed DLBCL patients, all of whom underwent PET/CT, IGR, FCM, BMC, and BMB at diagnosis. Survival outcomes were analyzed via Kaplan-Meier and Cox regression models. Novel prognostic models incorporating combined IGR and BMB results were developed in a training cohort.

Results

Compared to other detection methods, Clonal IGR BMI-positive were found the highest rate of 114 patients (31.3%), and IGR BM involvement-positive patients of DLBCL had the worst survival outcomes, especially among patients in stages I to III (P<0.001). Notably, PET/CT existed some limitations in BMI diagnosis, particularly in stage IV patients (P>0.05). Additionally, the combination of IGR and BMB demonstrated superior prognostic predictive capability for the patients in stage IV (PP<0.001). Multivariate analysis further confirmed that double-positive BMI of IGR and BMB was an independent prognostic factors of PFS (P=0.026) and OS (P=0.042). In addition, the novel IPI and NCCN-IPI stratification models were established by incorporating the combination of IGR and BMB in training group. The C-index of novel models were increased when IGR and BMB were supplemented in our cohort.

Discussion

Our results suggest that IGR is the most valuable methods for evaluating BMI compared to traditional detection methods. Adding the combination of IGR and BMB to the IPI and NCCN-IPI score may improve their predictive ability. In summary, IGR is essental for evaluation of BMI and provide an ideal method for disease staging and risk stratification in DLBCL patients in the rituximab era.

Magnetic Resonance Imaging and [18F]-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography-Guided Therapy Improves Survival in Upper Aerodigestive Tract NK/T-Cell Lymphoma, Nasal Type: A Prospective Cohort Study

BACKGROUND

To investigate the value of pretreatment nasopharyngeal and neck magnetic resonance imaging (NN-MRI) combined with positron emission tomography (PET)/CT-guided therapy for improving survival in upper aerodigestive tract NK/T-cell lymphoma (UADT-NKTL) patients.

METHODS

We performed a prospective cohort study including 171 untreated patients histologically diagnosed with UADT-NKTL, of whom 71 patients received PET/CT combined with NN-MRI and the other 100 patients received PET/CT alone. The clinical stage of every patient was classified according to the Ann Arbor and TNM staging systems. Clinical stage, target volume delineation, and survival were evaluated and compared for PET/CT with and without NN-MRI.

RESULTS

By detecting additional local lesions, NN-MRI upgraded the clinical stages on the basis of the Ann Arbor staging system and TNM staging system compared to the results of PET/CT (9/71, p = 0.011; 11/71, p = 0.019, respectively), which revised the target volume delineation of radiotherapy (9/71) in the PET/CT-MRI group. Compared with those in the PET/CT group, 3-year local recurrence-free survival was prolonged in the PET/CT-MRI group (100% vs. 74.9%; p < 0.001), and 3-year overall survival and progression-free survival were better in the PET/CT-MRI group (84.5% vs. 76.3%, p = 0.04 and 78.3% vs. 67.3%, p = 0.03, respectively).

CONCLUSION

NN-MRI and PET/CT-guided therapy could complementarily assist in optimizing the determination of clinical stage and target delineation, which could improve the prognosis of UADT-NKTL patients.

Long-Term Cognitive Outcomes in Adult Patients Receiving Chimeric Antigen Receptor T-Cell Therapies

BACKGROUND

CAR T-cell therapy (CAR-T) is leading to durable responses in patients with cancer but there is concern that cytokine release syndrome (CRS) and neurotoxicity may impact survivors' cognitive function. We assessed long-term cognitive function in CAR-T recipients and examine factors associated with change in cognition over time.

METHODS

We assessed perceived cognition (Functional Assessment of Cancer Therapy-Cognition) and neurocognitive performance (standardized neuropsychological battery) in adult patients prior to receiving CAR-T and at 6 month follow-up. We examined changes in cognitive outcomes using paired T-tests. We used univariate and multivariate linear regression models to explore whether patient-, disease-, or CAR-T specific factors were associated with change in cognition over time.

RESULTS

We included 106 participants (mean age = 62.7 years, 60.4% male, 56.6% diagnosed with non-Hodgkin´s lymphoma), of whom 70 reported perceived cognition data and 26 underwent neurocognitive performance assessments at both timepoints. There were no changes in perceived cognition (P = .560), overall neurocognitive performance (P = .924), or neurocognitive domains (P´s > .05) from baseline to 6 months post CAR-T. At 6 months, 32.9% reported improved, 47.1% stable, and 20.0% declined perceived cognition relative to baseline. In unadjusted analyses, progressive disease (β = -8.86, P = .012), baseline elevated C-reactive protein (β = -5.60, P = .076) and baseline neurologic comorbidity (β = -11.4, P = .052) were numerically associated with worse perceived cognition over time. In multivariate analyses, only progressive disease was statistically significantly associated with worse perceived cognition (β = -7.32, P = .032) over time.

CONCLUSIONS

We found stable cognition among CAR-T recipients and identified an association of therapy response with change in perceived cognition over time.

Transplant and Nontransplant Salvage Therapy in Pediatric Relapsed or Refractory Hodgkin Lymphoma: The EuroNet-PHL-R1 Phase 3 Nonrandomized Clinical Trial

Importance

The current standard-of-care salvage therapy in relapsed/refractory classic Hodgkin lymphoma (cHL) includes consolidation high-dose chemotherapy (HDCT)/autologous stem cell transplant (aSCT).

Objective

To investigate whether presalvage risk factors and fludeoxyglucose-18 (FDG) positron emission tomography (PET) response to reinduction chemotherapy can guide escalation or de-escalation between HDCT/aSCT or transplant-free consolidation with radiotherapy to minimize toxic effects while maintaining high cure rates.

Design, Setting, and Participants

EuroNet-PHL-R1 was a nonrandomized clinical trial that enrolled patients younger than 18 years with first relapsed/refractory cHL across 68 sites in 13 countries in Europe between January 2007 and January 2013. Data were analyzed between September 2022 and July 2024.

Intervention

Reinduction chemotherapy consisted of alternating IEP (ifosfamide, etoposide, prednisolone) and ABVD (adriamycin, bleomycin, vinblastine, dacarbazine). Patients with low-risk disease (late relapse after 2 cycles of first-line chemotherapy and any relapse with an adequate response after 1 IEP/ABVD defined as complete metabolic response on FDG-PET and at least 50% volume reduction) received a second IEP/ABVD cycle and radiotherapy (RT) to all sites involved at relapse. Patients with high-risk disease (all primary progressions and relapses with inadequate response after 1 IEP/ABVD cycle) received a second IEP/ABVD cycle plus HDCT/aSCT with or without RT.

Main Outcomes and Measures

The primary end point was 5-year event-free survival. Secondary end points were overall survival (OS) and progression-free survival (PFS). PFS was identical to event-free survival because no secondary cancers were observed. PFS data alone are presented for simplicity.

Results

Of 118 patients analyzed, 58 (49.2%) were female, and the median (IQR) age was 16.3 (14.5-17.6) years. The median (IQR) follow-up was 67.5 (58.5-77.0) months. The overall 5-year PFS was 71.3% (95% CI, 63.5%-80.1%), and OS was 82.7% (95% CI, 75.8%-90.1%). For patients in the low-risk group (n = 59), 41 received nontransplant salvage with a 5-year PFS of 89.7% (95% CI, 80.7%-99.8%) and OS of 97.4% (95% CI, 92.6%-100%). In contrast, 18 received HDCT/aSCT off protocol, with a 5-year PFS of 88.9% (95% CI, 75.5%-100%) and OS of 100%. All 59 patients with high-risk disease received HDCT/aSCT (and 23 received post-HDCT/aSCT RT) with a 5-year PFS of 53.3% (95% CI, 41.8%-67.9%) and OS of 66.5% (95% CI, 54.9%-80.5%).

Conclusion and Relevance

In this nonrandomized clinical trial, FDG-PET response-guided salvage in relapsed cHL may identify patients in whom transplant-free salvage achieves excellent outcomes. HDCT/aSCT may be reserved for primary progression and relapsed cHL with inadequate response.

Trial Registration

ClinicalTrials.gov Identifier: NCT00433459.

Primary mediastinal large B-cell Lymphoma: Biological features, clinical characteristics and current treatment strategies

Primary mediastinal large B-cell lymphoma (PMBCL) is a distinct subtype of B-cell lymphoma, representing a clinical and therapeutic challenge due to its unique presentation, histopathological features, and treatment response. It primarily affects young adults, with a significant female preponderance, and is characterized by a large anterior mediastinal mass that causes compressive symptoms. Despite its aggressive nature, PMBCL patients have a favorable prognosis, with a 5-year survival rate exceeding 80% when early remission is achieved through first-line therapy. Drawing on the significant scientific therapeutic advances over recent years, this review focuses on the evolving treatment strategies for PMBCL patients. Anthracycline- and rituximab-containing regimens are the mainstays of first-line approaches, often followed by mediastinal radiation therapy. However, concerns regarding long-term toxicities have led to a reevaluation of treatment protocols, suggesting that radiotherapy can be safely omitted in patients who achieve a complete metabolic response after induction therapy, according to a PET-guided approach. Furthermore, new targeted therapies such as PD-1 inhibitors and CAR-T cell immunotherapy, have shown promising results in refractory or relapsed PMBCL.

Radionuclide treatments of cancer: molecular mechanisms, biological responses, histopathological changes, and role of PET imaging

Radiation treatments [radiotherapy and radionuclide treatments (RNTs)] are one of the main and effective treatment modalities of cancer. Globally, the number of cancer patients treated with radionuclides are much less as compared to number of radiotherapy cases but with the development of new radiotracers, most notably 177 Lu and 225 Ac-labeled prostate-specific membrane antigen ligands, and 223 Ra-dichloride for prostate cancer and 177 Lu-somatostatin analogs for neuroendocrine tumors, there is a significant rise in RNTs in the last decade. As therapeutic applications of nuclear medicine is on the rise, the aim of this review is to summarize biological responses to radiation treatments and molecular mechanisms of radiation-induced cell death (e.g. ionization, DNA damages such as double-strand breaks, DNA repair mechanisms, types of cell deaths such as apoptosis, necrosis, and immunogenic cell death), histopathological changes with radiation treatments, and role of PET imaging in RNTs as part of radionuclide theranostics for selecting and planning patients for RNTs, dosimetry, predicting and assessing response to RNTs, predicting toxicities, and other possible PET findings which may be seen after RNTs such as activation of immune system.

Safety and efficacy of anti-CD30 CAR-T cell therapy in relapsed/refractory classic Hodgkin lymphoma: a systematic review and meta-analysis

BACKGROUND

Relapsed/refractory classic Hodgkin lymphoma (R/R cHL) remains challenging to treat, and anti-CD30 chimeric antigen receptor T (CAR-T) cell therapy may be effective. This meta-analysis investigates the efficacy and safety of anti-CD30 CAR-T cell therapy for treating R/R cHL.

METHODS

A systematic literature search of PubMed, Cochrane, Embase, ClinicalTrials.gov, and Web of Science databases was conducted until February 2024. The odds ratio (OR) with a 95% confidence interval (CI) was analysed using Review Manager 5.4. Outcomes including overall response rate (ORR), complete response (CR), partial response (PR), progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were extracted for meta-analysis. We used the Methodological Index for Non-Randomized Studies (MINORS) to evaluate the quality of the included literature.

RESULTS

A total of 151 participants from 8 records were included. Meta-analysis showed the ORR of CD30 CAR-T cell therapy for R/R cHL was 57% (95%CI 0.36-0.76, P = 0.50), with a CR of 34% (95%CI 0.13-0.64, P = 0.29) and a PR of 32% (95%CI 0.15-0.55, P = 0.12). With the median follow-up range from 9.5 to 71.5 months, the 1-year PFS was 39% (95% CI 0.30-0.49, P = 0.04), and the 1-year OS was 89% (95% CI 0.65-0.97, P = 0.005). The most common hematologic AE was leukopenia (72%, 95% CI: 0.50-0.87), and the most common non-hematological AE was cytokine release syndrome (CRS) (43%, 95% CI: 0.14-0.76). The grade ≥ 3 AEs was 66% (95%CI 0.06-0.98, I2 = 93%, P = 0.70), 34% (95%CI 0.07-0.78, I2 = 85%, P = 0.51) in neutropenia and thrombocytopenia, respectively. All AEs were tolerable and resolved with treatment.

CONCLUSION

Current evidence suggests that anti-CD30 CAR-T cell therapy is effective and safe in treating R/R cHL and is worth considering as a viable therapeutic option.

Prognostic value of pre-treatment 18F-FDG PET uptake for nasopharyngeal carcinoma

PURPOSE

To evaluate the prognostic value of maximal standardized uptake values (SUVmax) from serial fluor-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Fifty-two patients with NPC who underwent 18F-FDG PET/CT scan before radiotherapy with/without chemotherapy were reviewed retrospectively. Twenty-seven patients (52%) were applied 3-D conformal radiotherapy and 25 patients (48%) applied intensity-modulated radiotherapy (IMRT). Fourteen (27%) patients were given neoadjuvant chemotherapy and forty-four (84.6%) patients were given concomitant and adjuvant chemotherapy.

RESULTS

Median follow-up time was 34 months (range 5.6-66.4 months). Forty-four (84.6%) patients were alive at last follow-up and eight (15.4%) had died. The best cut-off value of the SUVmax for the primary tumor site (SUVmax-PT) was 13 and 9 for the lymph nodes (SUVmax-LN). Patients with SUVmax-PT ≥ 13.0 and SUVmax-LN ≥ 9 had a significantly higher risk for the development of the distant metastases (p = 0.044 and p = 0.038). DFS was affected in patients with SUVmax-PT ≥ 13 (log rank χ 2 = 2.54, p = 0.017) and was significantly lower in patients with SUVmax-LN ≥ 9 for the lymph nodes (log rank χ 2 = 5.81, p = 0.013). OS was not affected by SUV levels. A multivariate Cox proportional hazard model of DFS included age (≥ 40), SUVmax-LN (< 9), T stage (T1-2) and neoadjuvant chemotherapy are significantly better prognosis for the DFS.

CONCLUSION

18F-FDG PET/CT uptake before treatment, as determined by SUVmax, may be a valuable tool to evaluate prognosis in NPC patients.

Long-term follow-up of bulky classic Hodgkin lymphoma managed with ABVD and PET-guided RT demonstrates excellent outcomes in PET-negative cases

The outcome of 221 patients with bulky (≥10 cm) classic Hodgkin lymphoma (cHL) treated with doxorubicin, bleomycin, vinblastine, dacarbazine and consolidative radiotherapy (RT) only in those with a positive end-of-treatment (EOT) positron emission tomography (PET) scan was evaluated. With a median follow-up of 9.6 years, 5- and 10-year progression-free survival (PFS) in EOT PET-negative cases were 94.0% and 90.4%, respectively, and in PET-positive cases, 5/10-year PFS was 64.6% (p < 0.001), with 15% overall receiving RT. Five-year PFS for Deauville (D) score DX/D1-3 was 93.6%, compared with D4 66.7% (p < 0.001) and D5 33.3% (p < 0.001). Omission of RT in EOT PET-negative cases is associated with excellent long-term outcomes in bulky cHL.

The Value of Bone Marrow Assessment by FDG PET/CT, Biopsy and Aspirate in the Upfront Evaluation of Mantle Cell Lymphoma: A Nationwide Cohort Study

BACKGROUND

Assessment of bone marrow infiltration (BMI) is part of the initial staging of mantle cell lymphoma (MCL), although BMI evaluated by biopsy (BMB) is not considered significant in the MIPI scales, and standardized recommendations remain lacking.

OBJECTIVES

To evaluate the accuracy and prognostic impact of BMI assessed by PET/CT and BMB in a large series of MCL patients.

METHODS

We deconstructed the IPI-NCCN, MIPI, and MIPI-c indices and considered BMI as positive if indicated by a BMB, PET/CT scan, or a combination of both.

RESULTS

In the total cohort (n = 148), 110 patients had BMI detected by BMB and 33 by PET/CT. The sensitivity of BMB was higher than that of PET/CT (94.8% vs. 28.4%), as were its negative predictive value (84.2% vs. 27.8%) and accuracy (95.9% vs. 43.9%). In the total cohort, BMI detected by PET/CT showed a significant predictive value for PFS (p = 0.027), while BMB demonstrated independent prognostic value only in combination with PET/CT (p = 0.025). Among intensively treated patients (n = 128), PET/CT had significant clinical impact on PFS (p = 0.030), and when combined with BMB, it provided independent prognostic value for both PFS and OS (p = 0.026 and p = 0.033, respectively). Based on these findings, we propose a prognostic model (MCL-PET-I) that incorporates BMI by PET/CT, allowing for the identification of three groups with distinct clinical outcomes (p < 0.0001 for PFS and p = 0.00025 for OS).

CONCLUSIONS

In the upfront work of MCL, PET/CT-based BMI has greater prognostic impact, while BMB remains essential for staging. We propose the MCL-PET-I prognostic index, which effectively differentiates between clinical risk groups.

Circulating Tumor DNA Sequencing for Biologic Classification and Individualized Risk Stratification in Patients With Hodgkin Lymphoma

PURPOSE

Current clinical challenges in Hodgkin lymphoma (HL) include difficult-to-treat relapsed/refractory disease and considerable long-term toxicities of treatment. Since clinical risk factors lack discriminatory power, intensity of therapy is mainly based on tumor burden. Exploring HL genetics and tumor microenvironment (TME) might provide valuable insights for improved risk stratification.

MATERIALS AND METHODS

In this study, we applied circulating tumor DNA sequencing to 243 patients obtained from pivotal German Hodgkin Study Group trials to identify subtypes of HL. Independent validation of the subtypes was performed in 96 patients treated in the EuroNet-PHL-C2 study. Outcome differences of subtypes were assessed in an event-enriched clinical validation cohort comprising 72 patients from the HD21 trial, using a refined, validated, and clinically feasible assay.

RESULTS

We propose a biologic classification of HL consisting of three distinct subtypes: inflammatory immune escape HL is characterized by frequent copy-number variations including immune escape variants such as high-level amplifications of the PD-L1 locus and an inflammatory TME. Virally-driven HL is associated with Epstein-Barr virus and/or human herpesvirus 6 and an inflammatory TME with neutrophils and macrophages, while the tumor mutational burden (TMB) is low. Oncogene-driven HL is defined by a high TMB, recurrent mutations in oncogenic drivers such as TNFAIP3, ITPKB, and SOCS1, and a cold TME. A refined and validated assay version aiming at clinically feasible risk stratification showed significant progression-free survival differences between subtypes. In addition, assessment of minimal residual disease (MRD) allowed for the detection of patients at very high risk of relapse within the subtypes.

CONCLUSION

We propose a clinically feasible, noninvasive method for individualized risk stratification and MRD monitoring in patients with HL on the basis of circulating tumor DNA sequencing.

Benefits of BV-AVD (Brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine) versus ABVD (doxorubicin hydrochloride, bleomycin sulfate, vinblastine sulfate, dacarbazine) in patients with advanced-stage Hodgkin's lymphoma: an analysis of the ECHELON 1 trial by the GATLA group using the Delphi Method

INTRODUCTION

The BV-AVD (Brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine) combination for first-line treatment of advanced stage Hodgkin's lymphoma has been approved by regulatory authorities and included in international guidelines. However, several factors influence its incorporation as standard of care.

MATERIALS AND METHODS

A group of experts from different institutions was identified and, using the Delphi method, an analysis of the results of the ECHELON 1 trial for the indication of BV-AVD over ABVD (doxorubicin hydrochloride, bleomycin sulfate, vinblastine sulfate, dacarbazine) in patients with Hodgkin's lymphoma Stages III and IV in Argentina was done. The clinical and academic experience of the authors and the context of the Argentine healthcare system were considered.

RESULTS AND DISCUSSION

Seven statements on general aspects of the management of Hodgkin's lymphoma and nine on specific aspects related to the use of BV-AVD over ABVD reached a consensus of agreement. There was a strong expert consensus in favor of indicating BV-AVD in the presence of extranodal disease or pulmonary disease. Moderate to severe neuropathy, pregnancy and drug allergy were considered absolute contraindications to prescribe BV.

CONCLUSIONS

The authors agreed that BV-AVD could be considered a new treatment option in high-risk patients. However health system-dependent factors (such as high cost, lack of availability, reimbursement difficulties, irregular delivery, and issues with granulocyte-colony stimulating factor availability) could pose limitations for this prescription. While awaiting new data from clinical trials and real-world studies, these recommendations can represent a useful tool for hematologists in different parts of the world.

PET/CT Response Assessment in Pediatric Hodgkin Lymphoma: Does Deauville Score 3 Reflect Negativity?

BACKGROUND

FDG PET is required for the staging and response evaluation of pediatric Hodgkin lymphoma. This study aimed to evaluate the outcomes of pediatric patients with Hodgkin's lymphoma based on interim PET CT assessments of early response following second-cycle chemotherapy using the Deauville score (DS). It also determines whether DS-3 is providing an adequate or inadequate response.

METHODS

We conducted a retrospective cohort study including 504 pediatric patients with classic Hodgkin lymphoma who were treated with chemotherapy based on the Euro-Net protocol at the Children Cancer Hospital Egypt from March 2019 till the end of October 2022.

RESULTS

Patients with adequate response DS 1/2 and DS 3 showed nearly the same 3-year event-free survival (EFS) of 91.9% and 91.5%, respectively, compared with those patients with inadequate response DS 4/5, who showed an EFS of 80.4% ( P =0.001). Patients with a DS 3 at interim PET evaluation were considered negative as DS 1/2. Patients of DS 3 group who did not receive radiotherapy had a much worse 3-year EFS by the existence of positive B symptoms, an ESR>30, or an advanced stage. Radiation therapy did not improve the 3-year EFS in patients with an inadequate response (DS4/5) and poor prognostic characteristics. They still need more advanced treatment.

CONCLUSION

DS 1/2 and DS 3 had about the same 3-year EFS, which is better than the 3-year EFS of patients with DS 4/5. Therefore, we can classify DS 3 as having negative FDG PET CT uptake.

Metabolic tumor volume from baseline [18 F]FDG PET/CT at diagnosis improves the IPI stratification in patients with diffuse large B-cell lymphoma

PURPOSE

Although several different parameters of PET/CT were reported to be predictive of survival in DLBCL, the best parameter remains to be elucidated and whether it could improve the risk stratification of IPI in patients with DLBCL.

PROCEDURES

262 DLBCL patients including in the training and validation cohort were retrospectively analyzed in this study.

RESULTS

Among different parameters, MTV was identified as the optimal prognostic parameter with a maximum area under the curve (AUC) of 0.652 ± 0.112 than TLG and SDmax (0.645 ± 0.113 and 0.600 ± 0.117, respectively). Patients with high MTV were associated with inferior PFS (p < 0.001 and p = 0.021, respectively) and OS (p < 0.001 and p < 0.001, respectively) in both the training and validation cohort. The multivariate analysis revealed that high MTV was an unfavorable factor for PFS (relative ratio [RR], 2.295; 95% confidence interval [CI], 1.457-3.615; p < 0.01) and OS (RR, 2.929; 95% CI 1.679-5.109; p < 0.01) independent of IPI.

CONCLUSIONS

Further analysis showed MTV could improve the risk stratification of IPI for both PFS and OS (p < 0.01 and p < 0.01, respectively). In conclusion, our study suggests that MTV was an optimal prognostic parameter of PET/CT for survival and it could improve the risk stratification of IPI in DLBCL, which may help to guide treatment in clinical trial.

Automated Lugano Metabolic Response Assessment in 18F-Fluorodeoxyglucose-Avid Non-Hodgkin Lymphoma With Deep Learning on 18F-Fluorodeoxyglucose-Positron Emission Tomography

PURPOSE

Artificial intelligence can reduce the time used by physicians on radiological assessments. For 18F-fluorodeoxyglucose-avid lymphomas, obtaining complete metabolic response (CMR) by end of treatment is prognostic.

METHODS

Here, we present a deep learning-based algorithm for fully automated treatment response assessments according to the Lugano 2014 classification. The proposed four-stage method, trained on a multicountry clinical trial (ClinicalTrials.gov identifier: NCT01287741) and tested in three independent multicenter and multicountry test sets on different non-Hodgkin lymphoma subtypes and different lines of treatment (ClinicalTrials.gov identifiers NCT02257567, NCT02500407; 20% holdout in ClinicalTrials.gov identifier NCT01287741), outputs the detected lesions at baseline and follow-up to enable focused radiologist review.

RESULTS

The method's response assessment achieved high agreement with the adjudicated radiologic responses (eg, agreement for overall response assessment of 93%, 87%, and 85% in ClinicalTrials.gov identifiers NCT01287741, NCT02500407, and NCT02257567, respectively) similar to inter-radiologist agreement and was strongly prognostic of outcomes with a trend toward higher accuracy for death risk than adjudicated radiologic responses (hazard ratio for end of treatment by-model CMR of 0.123, 0.054, and 0.205 in ClinicalTrials.gov identifiers NCT01287741, NCT02500407, and NCT02257567, compared with, respectively, 0.226, 0.292, and 0.272 for CMR by the adjudicated responses). Furthermore, a radiologist review of the algorithm's assessments was conducted. The radiologist median review time was 1.38 minutes/assessment, and no statistically significant differences were observed in the level of agreement of the radiologist with the model's response compared with the level of agreement of the radiologist with the adjudicated responses.

CONCLUSION

These results suggest that the proposed method can be incorporated into radiologic response assessment workflows in cancer imaging for significant time savings and with performance similar to trained medical experts.

FDG-PET/CT is a powerful tool to predict and evaluate response to chimeric antigen receptor (CAR) T-cell therapy in Non-Hodgkin-Lymphoma (NHL)

Chimeric antigen receptor (CAR) T-cell therapy has dramatically shifted the landscape of treatment especially for Non-Hodgkin-Lymphoma (NHL). This study evaluates the role of fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in NHL treated with CAR T-cell therapy concerning response assessment and prognosis.We evaluated 34 patients with NHL who received a CAR T-cell therapy between August 2019 and July 2022. All patients underwent a pre-therapeutic FDG-PET/CT (PET-0) 6 days prior and a post-therapeutic FDG-PET/CT (PET-1) 34 days after CAR T-cell therapy. Deauville score (DS) was used for evaluation of response to therapy and compared to a minimum follow-up of 5 months.19/34 (55.9%) patients achieved DS ≤ 3 on PET-1, the remaining 15 (44.1%) patients had DS > 3 on PET-1. 14/19 patients with DS ≤ 3 on PET-1 had no relapsed or refractory (r/r)-disease and were still alive at last follow-up. The other 5 patients had r/r-disease and 4 of these died. Except for two patients who had no r/r-disease, all other patients (13/15) with DS > 3 on PET-1 had r/r-disease and 12 of these subsequently died. Patients with DS ≤ 3 on PET-1 had significantly better progression free survival (PFS; HR: 5.7; p < 0.01) and overall survival (OS; HR: 5.0; p < 0.01) compared to patients with DS > 3 on PET-1. In addition, we demonstrated that patients with DS ≤ 4 on PET-0 tended to have longer PFS (HR: 3.6; p = 0.05).Early FDG-PET/CT using the established DS after CAR T-cell therapy is a powerful tool to evaluate response to therapy.

Optimization of older adults by a geriatric assessment-guided multidisciplinary clinic before CAR T-cell therapy

ABSTRACT

The optimal means of assessing candidacy of older adults (≥65 years) for chimeric antigen receptor T-cell (CAR-T) therapy are unknown. We explored the role of a geriatric assessment (GA)-guided multidisciplinary clinic (GA-MDC) in selecting and optimizing older adults for CAR-T. Sixty-one patients were evaluated in a GA-MDC (median age, 73 years; range, 58-83). A nonbinding recommendation ("proceed" or "decline") regarding suitability for CAR-T was provided for each patient based on GA results. Fifty-three patients ultimately received CAR-T (proceed, n = 47; decline, n = 6). Among patients who received B-cell maturation antigen (BCMA)-directed (n = 11) and CD19-directed CAR-T (n = 42), the median overall survival (OS) was 14.2 months and 16.6 months, respectively. GA uncovered high rates of geriatric impairment among patients proceeding to CAR-T therapy, with fewer impairments in those recommended "proceed." Patients recommended "proceed" had shorter median length of stay (17 vs 31 days; P = .05) and lower rates of intensive care unit admission (6% vs 50%; P = .01) than those recommended "decline." In patients receiving CD19- and BCMA-directed CAR-T therapy, a "proceed" recommendation was associated with superior OS compared with "decline" (median, 16.6 vs 11.4 months [P = .02]; and median, 16.4 vs 4.2 months [P = .03], respectively). When controlling for Karnofsky performance status, C-reactive protein, and lactate dehydrogenase at time of lymphodepletion, the GA-MDC treatment recommendation remained prognostic for OS (hazard ratio, 3.26; P = .04). Patients optimized via the GA-MDC without serious vulnerabilities achieved promising outcomes, whereas patients with high vulnerability experienced high toxicity and poor outcomes after CAR-T therapy.

End-of-treatment 18[F]-FDG PET can predict early progression in patients receiving bendamustine-rituximab for follicular lymphoma in first relapse: a prospective West Japan hematology Study Group (W-JHS) NHL01 trial

Response determined by 18[F]-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)-CT after induction therapy can predict progression-free survival (PFS) in follicular lymphoma (FL). However, little prospective research has examined the significance of PET after second-line therapy. We conducted a prospective multicenter phase II trial (W-JHS NHL01) of bendamustine plus rituximab (BR) without rituximab maintenance for FL in first relapse. This study aimed to evaluate the usefulness of end-of-treatment (EOT)-PET for predicting PFS in FL patients in first relapse. EOT-PET examinations were performed between 6 and 8 weeks from the start of the last BR cycle. The primary endpoint was 1-year PFS. Key secondary endpoints were overall response rate (ORR), complete response rate (CRR), and 1-year overall survival (OS). Seventy-five patients were enrolled, and 8 were excluded from analysis. ORR was 86.6% and CRR was 59.7%. One-year PFS was 88.9% (95% confidence interval [CI] 80.7-94.3%) and 1-year OS in 75 patients was 97.3% (95% CI 89.6-99.3%). One-year PFS was significantly inferior in EOT-PET-positive patients (n = 9) compared with PET-negative patients (n = 58) (77.8% vs. 93.1%; p = 0.02). We confirmed that EOT-PET after second-line BR therapy could predict early progression in FL patients in first relapse.

Pulmonary lesions in early response assessment in pediatric Hodgkin lymphoma: prevalence and possible implications for initial staging

BACKGROUND

Disseminated pulmonary involvement in pediatric Hodgkin lymphoma (pHL) is indicative of Ann Arbor stage IV disease. During staging, it is necessary to assess for coexistence of non-malignant lung lesions due to infection representing background noise to avoid erroneously upstaging with therapy intensification.

OBJECTIVE

This study attempts to describe new lung lesions detected on interim staging computed tomography (CT) scans after two cycles of vincristine, etoposide, prednisolone, doxorubicin in a prospective clinical trial. Based on the hypothesis that these new lung lesions are not part of the underlying malignancy but are epiphenomena, the aim is to analyze their size, number, and pattern to help distinguish true lung metastases from benign lung lesions on initial staging.

MATERIALS AND METHODS

A retrospective analysis of the EuroNet-PHL-C1 trial re-evaluated the staging and interim lung CT scans of 1,300 pediatric patients with HL. Newly developed lung lesions during chemotherapy were classified according to the current Fleischner glossary of terms for thoracic imaging. Patients with new lung lesions found at early response assessment (ERA) were additionally assessed and compared to response seen in hilar and mediastinal lymph nodes.

RESULTS

Of 1,300 patients at ERA, 119 (9.2%) had new pulmonary lesions not originally detectable at diagnosis. The phenomenon occurred regardless of initial lung involvement or whether a patient relapsed. In the latter group, new lung lesions on ERA regressed by the time of relapse staging. New lung lesions on ERA in patients without relapse were detected in 102 (7.8%) patients. Pulmonary nodules were recorded in 72 (5.5%) patients, the majority (97%) being<10 mm. Consolidations, ground-glass opacities, and parenchymal bands were less common.

CONCLUSION

New nodules on interim staging are common, mostly measure less than 10 mm in diameter and usually require no further action because they are most likely non-malignant. Since it must be assumed that benign and malignant lung lesions coexist on initial staging, this benign background noise needs to be distinguished from lung metastases to avoid upstaging to stage IV disease. Raising the cut-off size for lung nodules to ≥ 10 mm might achieve the reduction of overtreatment but needs to be further evaluated with survival data. In contrast to the staging criteria of EuroNet-PHL-C1 and C2, our data suggest that the number of lesions present at initial staging may be less important.

Quarter-Century PET/CT Transformation of Oncology: Lymphoma

The clinical landscape of lymphomas has changed dramatically over the last 2 decades, including significant progress made in the understanding and utilization of imaging modalities and the available treatment options for both indolent and aggressive lymphomas. Since the introduction of hybrid PET/CT scanners in 2001, the indications of 18F-fluorodeoxyglucose (FDG) PET/CT in the management of lymphomas have grown rapidly. In today's clinical practice, FDG PET/CT is used in successful management of the vast majority patients with lymphomas.

Update on FDG-PET in pediatric lymphoma

Lymphoma represent the third most common malignant disease in childhood and adolescence. They are divided into pediatric Hodgkin lymphoma (P-HL) and pediatric non-Hodgkin lymphoma (P-NHL). In P-HL, excellent cure rates are achieved through combined modality treatment using chemotherapy and radiotherapy. For more than 20 years, FDG-PET has been an integral part of the treatment and guides its intensity through improved staging and precise assessment of chemotherapy response. In P-NHL, good cure rates are achieved with chemotherapy alone. At present FDG-PET plays only a subordinate role in the treatment setting. Its potential to contribute to treatment management is far from being fully utilised. In this article, the current status of FDG-PET in pediatric lymphoma is presented in detail. The core elements are the sections on staging and response assessment. In addition, challenges and pitfalls are discussed and future developments are outlined.

Predictive Value of Corrected 18 F-FDG PET/CT Baseline Parameters for Primary DLBCL Prognosis: A Single-center Study

Objective  The purpose of this study was to evaluate the prognostic significance of corrected baseline metabolic parameters in fluorodeoxyglucose positron emission tomography imaging ( 18 F-FDG PET/CT) for 3-year progression-free survival (PFS) in patients with primary diffuse large B cell lymphoma (DLBCL). Patients and Methods  Retrospective clinical and pathological data were collected for 199 patients of DLBCL diagnosed between January 2018 and January 2021. All patients underwent 18 F-FDG PET/CT scans without any form of treatment. The corrected maximum standardized uptake value (corSUVmax), corrected mean standardized uptake value (corSUVmean), corrected whole-body tumor metabolic volume sum (corMTVsum), and corrected total lesion glycolysis of whole body (corTLGtotal) were corrected using the SUVmean in a 1-cm diameter mediastinal blood pool (MBP) from the descending thoracic aorta of patients. Kaplan-Meier survival curves and Cox regression were used to examine the predictive significance of corrected baseline metabolic parameters on 3-year PFS of patients. The incremental values of corrected baseline metabolic parameters were evaluated by using Harrell's C-indices, receiver operating characteristic, and Decision Curve Analysis. Results  The multivariate analysis revealed that only the National Comprehensive Cancer Network (NCCN)-International Prognostic Index (IPI) and corMTVsum had an effect on 3-year PFS of patients ( p  < 0.05, respectively). The Kaplan-Meier survival analysis demonstrated significant differences in PFS between the risk groups classified by corSUVsum, corMTVsum, and corTLGtotal (log-rank test, p  < 0.05). The predictive model composed of corMTVsum and corTLGtotal surpasses the predictive performance of the model incorporating MTVsum and TLGtotal. The optimal performance was observed when corMTVsum was combined with NCCN-IPI, resulting in a Harrell's C index of 0.785 and area under the curve values of 0.863, 0.891, and 0.947 for the 1-, 2-, and 3-year PFS rates, respectively. Conclusion  The corMTVsum offers significant prognostic value for patients with DLBCL. Furthermore, the combination of corMTVsum with the NCCN-IPI can provide an accurate prediction of the prognosis.

Ultra-low dose CT scanning for PET/CT

BACKGROUND

The use of computed tomography (CT) for attenuation correction (AC) in whole-body PET/CT can result in a significant contribution to radiation exposure. This can become a limiting factor for reducing considerably the overall radiation exposure of the patient when using the new long axial field of view (LAFOV) PET scanners. However, recent CT technology have introduced features such as the tin (Sn) filter, which can substantially reduce the CT radiation dose.

PURPOSE

The purpose of this study was to investigate the ultra-low dose CT for attenuation correction using the Sn filter together with other dose reduction options such as tube current (mAs) reduction. We explore the impact of dose reduction in the context of AC-CT and how it affects PET image quality.

METHODS

The study evaluated a range of ultra-low dose CT protocols using five physical phantoms that represented a broad collection of tissue electron densities. A long axial field of view (LAFOV) PET/CT scanner was used to scan all phantoms, applying various CT dose reduction parameters such as reducing tube current (mAs), increasing the pitch value, and applying the Sn filter. The effective dose resulting from the CT scans was determined using the CTDIVol reported by the scanner. Several voxel-based and volumes of interest (VOI)-based comparisons were performed to compare the ultra-low dose CT images, the generated attenuation maps, and corresponding PET images against those images acquired with the standard low dose CT protocol. Finally, two patient datasets were acquired using one of the suggested ultra-low dose CT settings.

RESULTS

By incorporating the Sn filter and adjusting mAs to the lowest available value, the radiation dose in CT images of PBU-60 phantom was significantly reduced; resulting in an effective dose of nearly 2% compared to the routine low dose CT protocols currently in clinical use. The assessment of PET images using VOI and voxel-based comparisons indicated relative differences (RD%) of under 6% for mean activity concentration (AC) in the torso phantom and patient dataset and under 8% for a source point in the CIRS phantom. The maximum RD% value of AC was 14% for the point source in the CIRS phantom. Increasing the tube current from 6 mAs to 30 mAs in patients with high BMI, or with arms down, can suppress the photon starvation artifact, whilst still preserving a dose reduction of 90%.

CONCLUSIONS

Introducing a Sn filter in CT imaging lowers radiation dose by more than 90%. This reduction has minimal effect on PET image quantification at least for patients without Body Mass Index (BMI) higher than 30. Notably, this study results need validation using a larger clinical PET/CT dataset in the future, including patients with higher BMI.

Outcomes of Patients Treated With RCHOP With a PET-Adapted Approach for Consolidative Radiotherapy: A Retrospective Single-Center Study at the Royal Marsden Hospital

BACKGROUND

Treatment with CHOP-based chemotherapy with consolidative radiotherapy (CRT) for primary mediastinal B cell lymphoma (PMBCL) has been the standard approach in the pre-rituximab era. Overtreatment with CRT for patients who may have already been cured by primary immunochemotherapy in the rituximab era is a significant concern due to the long-term toxicity associated with radiotherapy. Positron emission tomography (PET) may help to identify patients who may not benefit from further CRT.

METHODS

We conducted a retrospective review of patients treated at the Royal Marsden Hospital between 2003 and 2020 for PMBCL to assess CRT use and survival outcomes.

RESULTS

Forty-three patients were identified, with 95% of the patients receiving R-CHOP. CRT was given in 5 patients. Five-year event-free survival was 79% (95% confidence interval: 64%-89%) and 5-year overall survival was 88% (95% confidence interval: 73%-95%). Seven of 9 patients with DS4 did not receive CRT and instead monitored with serial PET scans. None of these 7 patients relapsed in the mediastinum.

CONCLUSION

CRT may be omitted in patients with a negative end of treatment PET scans; however, careful observation may also obviate the need for CRT in PET positive patients.

PET/CT in the Evaluation of CAR-T Cell Immunotherapy in Hematological Malignancies

Chimeric antigen receptor (CAR)-T cell-based immunotherapy has emerged as a path-breaking strategy for certain hematological malignancies. Assessment of the response to CAR-T therapy using quantitative imaging techniques such as positron emission tomography/computed tomography (PET/CT) has been broadly investigated. However, the definitive role of PET/CT in CAR-T therapy remains to be established. [18F]FDG PET/CT has demonstrated high sensitivity and specificity for differentiating patients with a partial and complete response after CAR-T therapy in lymphoma. The early therapeutic response and immune-related adverse effects such as cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome can also be detected on [18F]FDG PET images. In otherwise asymptomatic lymphoma patients with partial response following CAR-T therapy, the only positive findings could be abnormal PET/CT results. In multiple myeloma, a negative [18F]FDG PET/CT after receiving B-cell maturation antigen-directed CAR-T therapy has been associated with a favorable prognosis. In leukemia, [18F]FDG PET/CT can detect extramedullary metastases and treatment responses after therapy. Hence, PET/CT is a valuable imaging tool for patients undergoing CAR-T therapy for pretreatment evaluation, monitoring treatment response, assessing safety, and guiding therapeutic strategies. Developing guidelines with standardized cutoff values for various PET parameters and tumor cell-specific tracers may improve the efficacy and safety of CAR-T therapy.

A Systematic Review on Childhood Non-Hodgkin Lymphoma: An Overlooked Phenomenon in the Health and Research Sector of Bangladesh

Globally, childhood cancer, particularly non-Hodgkin lymphomas (NHLs), is a prevalent concern. However, the difficulty becomes even more distressing in lower-middle-income nations such as Bangladesh. The insufficiency of research, resources, inadequate guidelines, expensive treatment costs, and specialized knowledge exacerbate the challenges associated with the treatment of certain types of cancers. Our investigation looked extensively into the circumstances prevailing in Bangladesh, with the objective of providing a comprehensive overview of the current status and approaches to managing NHL in the country. Through this work, our intention was to illuminate the domains that require immediate focus and assistance. To get insight into the present state of NHL in Bangladesh, our analysis focused on a selection of seven research articles and two case reports published between 2018 and 2023. In order to ensure the integrity and consistency of our review, we conducted a detailed selection procedure, employing the systematic PRISMA review methodology. From a pool of 294 papers, we selected the ones that met our predetermined criteria. These papers were sourced from reputable academic databases, such as Google Scholar and PubMed. The findings of our study indicate a higher prevalence of NHL among children in Bangladesh compared to Hodgkin lymphoma (HL). Additionally, this phenomenon exhibits a higher prevalence among male individuals. Our study revealed that in Bangladesh, there is a lack of a dedicated guideline or research center specifically focused on NHL. Additionally, the number of research centers and research dedicated to cancer treatment as a whole is limited. Our research aims to offer a complete analysis of NHL in the context of Bangladesh, with the intention of offering valuable guidance to healthcare professionals and policymakers. The utilization of our research outcomes has the potential to enhance patient care, facilitate the development of more effective clinical protocols, and promote greater accessibility and affordability of therapies. This has the potential to provide improved cancer care not only in Bangladesh but also in other comparable contexts worldwide.

Longitudinal patient-reported outcomes in patients receiving chimeric antigen receptor T-cell therapy

Chimeric antigen receptor T-cell therapy (CAR-T) has transformed the treatment for relapsed/refractory hematologic malignancies; however, data on patient-reported outcomes in CAR-T are limited. We conducted a longitudinal study of adults with hematologic malignancies receiving CAR-T. We assessed quality of life (QOL; functional assessment of cancer therapy-general), psychological distress (hospital anxiety and depression scale, patient health questionnaire-9, posttraumatic stress disorder [PTSD] checklist), and physical symptoms (Edmonton symptom assessment scale-revised) at baseline, 1 week, 1, 3, and 6 months after CAR-T. We used linear mixed models to identify factors associated with QOL trajectory. We enrolled 103 of 142 eligible patients (3 did not receive CAR-T). QOL (B = 1.96; P < .001) and depression (B = -0.32; P = .001) worsened by 1 week and improved by 6 months after CAR-T. At 6 months, 18%, 22%, and 22% reported clinically significant depression, anxiety, and PTSD symptoms, respectively. At 1 week, 52% reported severe physical symptoms, declining to 28% at 6 months after CAR-T. In unadjusted linear mixed models, worse Eastern Cooperative Oncology Group performance status (B = 1.24; P = .042), receipt of tocilizumab (B = 1.54; P = .042), and receipt of corticosteroids for cytokine release syndrome and/or neurotoxicity (B = 2.05; P = .006) were associated with higher QOL trajectory. After CAR-T, QOL declined, and depression increased early, followed by improvements in QOL, psychological distress, and physical symptoms by 6 months after infusion. A significant minority of patients reported substantial psychological distress and physical symptoms longitudinally.

Clinical applications of circulating tumor DNA in Hodgkin lymphoma

Hodgkin lymphoma is a B-cell lymphoma often affecting young adults. Outcomes following intensive chemo- and radiotherapy are generally favourable but leave patients at high risk for early and late toxicities frequently reducing quality of life. Relapsed/refractory disease is regularly difficult to treat and ultimately results in death in a relevant subset of patients. Current strategies for risk stratification and response evaluation rely on clinical features and imaging only, and lack discriminatory power to detect patients at risk for disease progression. Here, we explore how circulating tumor DNA sequencing might help to overcome these shortcomings. We provide an overview over recent technical and methodological developments and suggest potential use cases for different clinical situations. Circulating tumor DNA sequencing offers the potential to significantly augment current risk stratification strategies with the ultimate goal of further individualizing treatment strategies for patients with HL.

Characterization and outcome of post-transplant lymphoproliferative disorders within a collaborative study

Background

Post-transplant lymphoproliferative disorders (PTLD) are heterogeneous lymphoid disorders ranging from indolent polyclonal proliferations to aggressive lymphomas that can arise after solid organ transplantation (SOT) and allogeneic hematopoietic transplantation (allo-HSCT).

Methods

In this multi-center retrospective study, we compare patient characteristics, therapies, and outcomes of PTLD after allo-HSCT and SOT. Twenty-five patients (15 after allo-HSCT and 10 after SOT) were identified who developed PTLD between 2008 and 2022.

Results

Median age (57 years; range, 29-74 years) and baseline characteristics were comparable between the two groups (allo-HSCT vs SOT), but median onset of PTLD was markedly shorter after allo-HSCT (2 months vs. 99 months, P<0.001). Treatment regimens were heterogeneous, with reduction of immunosuppression in combination with rituximab being the most common first-line treatment strategy in both cohorts (allo-HSCT: 66%; SOT: 80%). The overall response rate was lower in the allo-HSCT (67%) as compared to the SOT group (100%). Consequently, the overall survival (OS) trended towards a worse outcome for the allo-HSCT group (1-year OS: 54% vs. 78%; P=0.58). We identified PTLD onset ≤150 days in the allo-HSCT (P=0.046) and ECOG >2 in the SOT group (P=0.03) as prognostic factors for lower OS.

Conclusion

PTLD cases present heterogeneously and pose unique challenges after both types of allogeneic transplantation.

Assessment of Response to Immunotherapy in Patients with Hodgkin Lymphoma: Towards Quantifying Changes in Tumor Burden Using FDG-PET/CT

Immune checkpoint inhibitors are currently the standard of care for many advanced solid tumors, and they have been recently approved for the treatment of relapsed/refractory Hodgkin lymphoma and primary mediastinal B cell lymphoma. Assessments of the response to immunotherapy may be complicated by the occurrence of the flare/pseudoprogression phenomenon, consisting of initial tumor enlargement and even the appearance of new lesions, followed by a response, which may initially be indistinguishable from true progression. There have been efforts to characterize and capture the new patterns of response observed during immunotherapy, namely, pseudoprogression and delayed response, and several immune-related response criteria have been proposed. Confirming progression on a subsequent scan and measuring the total tumor burden are both common in immune-related criteria. Due to the peculiarity of hematologic malignancies, lymphoma-specific immune-related criteria have been developed (LYRIC), and they have been evaluated in research studies in comparison to the Lugano Classification. In this review work, we illustrate the evolution of the response criteria in lymphomas from the first CT-based criteria to the development of the PET-based Lugano Classification, further refined to take into account the flare phenomenon encountered during immunotherapy. We also describe the additional contribution of PET-derived volumetric parameters to the interpretation of responses during immunotherapy.

Primary Lymphoproliferative Lung Diseases: Imaging and Multidisciplinary Approach

Lymphoproliferative lung diseases are a heterogeneous group of disorders characterized by primary or secondary involvement of the lung. Primary pulmonary lymphomas are the most common type, representing 0.5–1% of all primary malignancies of the lung. The radiological presentation is often heterogeneous and non-specific: consolidations, masses, and nodules are the most common findings, followed by ground-glass opacities and interstitial involvement, more common in secondary lung lymphomas. These findings usually show a prevalent perilymphatic spread along bronchovascular bundles, without a prevalence in the upper or lower lung lobes. An ancillary sign, such as a “halo sign”, “reverse halo sign”, air bronchogram, or CT angiogram sign, may be present and can help rule out a differential diagnosis. Since a wide spectrum of pulmonary parenchymal diseases may mimic lymphoma, a correct clinical evaluation and a multidisciplinary approach are mandatory. In this sense, despite High-Resolution Computer Tomography (HRCT) representing the gold standard, a tissue sample is needed for a certain and definitive diagnosis. Cryobiopsy is a relatively new technique that permits the obtaining of a larger amount of tissue without significant artifacts, and is less invasive and more precise than surgical biopsy.

Prognostic Value of 18F-FDG PET/CT in Diffuse Large B-Cell Lymphoma Treated with a Risk-Adapted Immunochemotherapy Regimen

Early identification of patients with diffuse large B-cell lymphoma (DLBCL) who are likely to experience disease recurrence or refractory disease after rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) would be useful for improving risk-adapted treatment strategies. We aimed to assess the prognostic value of 18F-FDG PET/CT parameters at baseline, interim, and end of treatment (EOT). Methods: We analyzed the prognostic impact of 18F-FDG PET/CT in 166 patients with DLBCL treated with a risk-adapted immunochemotherapy regimen. Scans were obtained at baseline, after 4 cycles of R-CHOP or 3 cycles of RR-CHOP (double dose of R) and 1 cycle of CHOP alone (interim) and 6 wk after completing therapy (EOT). Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier and the impact of clinical/PET factors assessed with Cox models. We also assessed the predictive ability of the recently proposed International Metabolic Prognostic Index (IMPI). Results: The median follow-up was 7.9 y. International Prognostic Index (IPI), baseline metabolic tumor volume (MTV), and change in maximum SUV (ΔSUVmax) at interim scans were statistically significant predictors for OS. Baseline MTV, interim ΔSUVmax, and EOT Deauville score were statistically significant predictors of PFS. Combining interim PET parameters demonstrated that patients with Deauville 4-5 and positive ΔSUVmax ≤ 70% at restaging (∼10% of the cohort) had extremely poor prognosis. The IMPI had limited discrimination and slightly overestimated the event rate in our cohort. Conclusion: Baseline MTV and interim ΔSUVmax predicted both PFS and OS with this sequential immunochemotherapy program. Combining interim Deauville score with interim ΔSUVmax may identify an extremely high-risk DLBCL population.

Is local review of positron emission tomography scans sufficient in diffuse large B-cell lymphoma clinical trials? A CALGB 50303 analysis

BACKGROUND

Quantitative methods of Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) interpretation, including the percent change in FDG uptake from baseline (ΔSUV), are under investigation in lymphoma to overcome challenges associated with visual scoring systems (VSS) such as the Deauville 5-point scale (5-PS).

METHODS

In CALGB 50303, patients with DLBCL received frontline R-CHOP or DA-EPOCH-R, and although there were no significant associations between interim PET responses assessed centrally after cycle 2 (iPET) using 5-PS with progression-free survival (PFS) or overall survival (OS), there were significant associations between central determinations of iPET ∆SUV with PFS/OS. In this patient cohort, we retrospectively compared local vs central iPET readings and evaluated associations between local imaging data and survival outcomes.

RESULTS

Agreement between local and central review was moderate (kappa = 0.53) for VSS and high (kappa = 0.81) for ∆SUV categories (<66% vs. ≥66%). ∆SUV ≥66% at iPET was significantly associated with PFS (p = 0.03) and OS (p = 0.002), but VSS was not. Associations with PFS/OS when applying local review vs central review were comparable.

CONCLUSIONS

These data suggest that local PET interpretation for response determination may be acceptable in clinical trials. Our findings also highlight limitations of VSS and call for incorporation of more objective measures of response assessment in clinical trials.

Prospective Evaluation of Quantitative F-18-FDG-PET/CT for Pre-Operative Thoracic Lymph Node Staging in Patients with Lung Cancer as a Target for Computer-Aided Diagnosis

Purpose: Pre-operative assessment of thoracic lymphonodal (LN) involvement in patients with lung cancer (LC) is crucial when choosing the treatment modality. Visual assessment of F-18-FDG-PET/CT (PET/CT) is well established, however, there is still a need for prospective quantitative data to differentiate benign from malignant lesions which would simplify staging and guide the further implementation of computer-aided diagnosis (CAD). Methods: In this prospective study, 37 patients with confirmed lung cancer (m/f = 24/13; age: 70 [52–83] years) were analyzed. All patients underwent PET/CT and quantitative data (standardized uptake values) were obtained. Histological results were available for 101 thoracic lymph nodes. Quantitative data were matched to determine cut-off values for delineation between benign vs. malignant lymph nodes. Furthermore, a scoring system derived from these cut-off values was established. Statistical analyses were performed through ROC analysis. Results: Quantitative analysis revealed the optimal cut-off values (p < 0.01) for the differentiation between benign and malignant thoracic lymph nodes in patients suffering from lung cancer. The respective areas under the curve (AUC) ranged from 0.86 to 0.94. The highest AUC for a ratio of lymph node to healthy lung tissue was 0.94. The resulting accuracy ranged from 78.2% to 89.1%. A dedicated scoring system led to an AUC of 0.93 with a negative predictive value of 95.4%. Conclusion: Quantitative analysis of F-18-FDG-PET/CT data provides reliable results for delineation between benign and malignant thoracic lymph nodes. Thus, quantitative parameters can improve diagnostic accuracy and reliability and can also facilitate the handling of the steadily increasing number of clinical examinations.

Relapse patterns in early-PET negative, limited-stage Hodgkin lymphoma (HL) after ABVD with or without radiotherapy-a joint analysis of EORTC/LYSA/FIL H10 and NCRI RAPID trials

In the H10 and RAPID randomised trials, chemotherapy+radiotherapy (combined modalities treatment, CMT) was compared with chemotherapy (C) in limited-stage Hodgkin lymphoma (HL), with negative early positron emission tomography (ePETneg). We analysed patterns of relapses in the H10 trial, validated findings in the RAPID trial and performed a combined analysis stratified by trial. The impact of radiotherapy (RT) on risk of relapse was studied using adjusted Cox models, with time-varying effects. In H10, 1,059 ePETneg patients were included (465 European Organisation for Research and Treatment of Cancer (EORTC) favourable [F], 594 unfavourable [U]). Among the F patients, 2/227 (1%) relapsed after CMT, 30/238 (13%) after C: of these relapses, 21/30 (70%) occurred in less than 2 years and 25/30 (83%) affected originally involved areas. Among the U group, 16/292 (5%) relapsed after CMT: 8/16 (50%) in less than 2 years, 11/16 (69%) in originally involved areas. After C 30/302 (10%) relapsed: 27/30 (90%) in less than 2 years, and 26/30 (87%) in originally involved areas. Similar results were observed in 419 ePETneg RAPID patients (241 F, 128 U, 50 unclassified): among F patients, 6/118 (5%) relapsed after CMT; 13/123 (11%) after C: 11/13 (85%) in less than 2 years and 11/13 (85%) affecting originally involved areas. In U patients, 3/65 (5%) relapsed after CMT and 5/63 (8%) after C. In both trials, omitting RT in ePETneg HL resulted in more early relapses, mainly affecting originally involved areas. RT significantly reduced risk of early relapses in the combined stratified analysis.

Comparison of bone marrow biopsy and fluorodeoxyglucose-positron emission tomography for the assessment of bone marrow infiltration in children with Hodgkin's lymphoma

PURPOSE

To compare bone marrow biopsy (BMB) with [18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (PET/CT) imaging in the demonstration of bone marrow involvement in children with Hodgkin's Lymphoma (HL) and to investigate the effectiveness of PET/CT imaging and thus the necessity for BMB at staging.

METHODS

Pediatric patients with HL, who underwent both bilateral iliac BMB and PET/CT imaging at disease staging were retrospectively analyzed. In determining bone marrow involvement (BMinv), BMB and/or first/follow-up PET/CT imaging were eligible for review.

RESULTS

Fifty-six patients were included. BMinv was detected by PET/CT imaging in 6/56 (10.7%), whereas the proportion was 3/56 (5.3%) in BMB specimens. Bone marrow biopsies and PET/CT images were concordant in 53/56 (94.6%) patients with BMB specimens missing three cases of BMinv detected by PET/CT. When diagnostic accuracy was calculated, sensitivity, specificity, positive predictive value and negative predictive values for PET/CT were 100%, 100%, 100%, 100%, respectively, and the same values for BMB were 50%, 100%, 100%, 94.3%, respectively.

CONCLUSIONS

The results of PET/CT and BMB for staging of pediatric HL patients were compatible, and PET/CT imaging was found to provide high diagnostic performance in determining BMinv. In keeping with earlier research, the current study showed that BMB may not be necessary in every patient at staging, and should be reserved for cases where PET/CT is inconclusive.

FDG PET/CT Maximum Tumor Dissemination to Predict Recurrence in Patients with Diffuse Large B-Cell Lymphoma

Purpose

We investigated the prognostic value of maximum tumor dissemination (Dmax), the distance between malignant lesions that were farthest apart, as assessed by fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), and other clinical factors in patients with diffuse large B-cell lymphoma (DLBCL).We investigated the prognostic value of maximum tumor dissemination (Dmax), the distance between malignant lesions that were farthest apart, as assessed by fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), and other clinical factors in patients with diffuse large B-cell lymphoma (DLBCL).

Methods

Patients who underwent FDG PET/CT for initial staging and treatment response evaluation of DLBCL were reviewed retrospectively. Baseline Dmax, maximum standardized uptake value, total summation of all metabolic tumor volumes (tMTV), and total summation of all total lesion glycolysis (tTLG) were measured. The treatment response was evaluated at the interim and end of first-line treatment (EOT) using the Deauville score (DS). FDG PET/CT parameters and other clinical factors including sex, age, serum lactate dehydrogenase (LDH) level, stage, performance status, and the International Prognostic Index (IPI) were analyzed to identify factors prognostic of the time to progression (TTP) and disease-specific survival (DSS).

Results

A total of 63 patients were included. Univariate survival analysis identified Dmax (> 275 mm), tMTV (> 180 mL), tTLG (> 1300), interim DS (≥ 4), and EOT DS (≥ 4) as significant predictors of poor TTP. Serum LDH level (> 640 IU/L), IPI (≥ 4), tMTV (> 180 mL), tTLG (> 1300), interim DS (≥ 4), and EOT DS (≥ 4) were significant predictors of DSS. After multivariate survival analysis, Dmax (P = 0.008) and EOT DS (P = 0.005) were independent predictors of TTP. EOT DS was an independent predictor of DSS (P = 0.029).

Conclusions

Dmax at the time of diagnosis and the EOT response assessed by FDG PET/CT provide useful prognostic information additive to the IPI in patients with DLBCL.

Haemophagocytic Lymphohistiocytosis Associated With Anaplastic Large-Cell Lymphoma in a Young Woman

Haemophagocytic lymphohistiocytosis is a syndrome of excessive immunological activation that can be triggered by various diseases, including haematological cancers. We report a case of a 25-year-old woman presenting with constitutional symptoms and a painful thoracic mass of four months duration. Laboratory exams showed pancytopenia, hypertriglyceridemia and extremely high serum ferritin levels. A whole-body computed tomography (CT) scan revealed splenomegaly and highlighted the mass on the deep tissues of the left breast; the biopsy was compatible with anaplastic large-cell lymphoma. Additionally, a bone marrow biopsy revealed haemophagocytosis, fulfilling the criteria for associated haemophagocytic lymphohistiocytosis. The patient was quickly sent for chemotherapy followed by autologous haematopoietic cell transplantation. She achieved a complete metabolic response and has been in clinical remission after nearly four years of follow-up. We emphasise the benefit of a timely diagnosis and intervention which were the keys to success in this case.

Iterated cross validation method for prediction of survival in diffuse large B-cell lymphoma for small size dataset

Efforts have been made to improve the risk stratification model for patients with diffuse large B-cell lymphoma (DLBCL). This study aimed to evaluate the disease prognosis using machine learning models with iterated cross validation (CV) method. A total of 122 patients with pathologically confirmed DLBCL and receiving rituximab-containing chemotherapy were enrolled. Contributions of clinical, laboratory, and metabolic imaging parameters from fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scans to the prognosis were evaluated using five regression models, namely logistic regression, random forest, support vector classifier (SVC), deep neural network (DNN), and fuzzy neural network models. Binary classification predictions for 3-year progression free survival (PFS) and 3-year overall survival (OS) were conducted. The 10-iterated fivefold CV with shuffling process was conducted to predict the capability of learning machines. The median PFS and OS were 41.0 and 43.6 months, respectively. Two indicators were found to be independent predictors for prognosis: international prognostic index and total metabolic tumor volume (MTVsum) from FDG PET/CT. For PFS, SVC and DNN (both with accuracy 71%) have the best predictive results, of which outperformed other algorithms. For OS, the DNN has the best predictive result (accuracy 76%). Using clinical and metabolic parameters as input variables, the machine learning methods with iterated CV method add the predictive values for PFS and OS evaluation in DLBCL patients.

Brentuximab Vedotin Plus AVD for First-Line Treatment of Early-Stage Unfavorable Hodgkin Lymphoma (BREACH): A Multicenter, Open-Label, Randomized, Phase II Trial

PURPOSE

The prognosis of patients with early-stage unfavorable Hodgkin lymphoma remains unsatisfactory. We assessed the efficacy and safety of brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine (BV-AVD) in previously untreated, early-stage unfavorable Hodgkin lymphoma (ClinicalTrials.gov identifier: NCT02292979).

METHODS

BREACH is a multicenter, randomized, open-label, phase II trial. Eligible patients were age 18-60 years with ≥ 1 unfavorable EORTC/LYSA criterion. Patients were randomly assigned (2:1) to four cycles of BV-AVD or standard doxorubicin, bleomycin, vincristine, and dacarbazine (ABVD), followed by 30 Gy involved node radiotherapy. The primary end point was the positron emission tomography (PET) response rate after two cycles by expert independent review using the Deauville score. The study was designed to test if the PET-negative rate after two cycles of BV-AVD was superior to 75%. We hypothesized a 10% increase in the PET-negative rate after two cycles of BV-AVD.

RESULTS

Between March 2015 and October 2016, 170 patients were enrolled. After two cycles, the primary end point of the study was met: 93 (82.3%; 90% CI, 75.3 to 88.0) of 113 patients in the BV-AVD arm were PET-negative (Deauville score 1-3) compared with 43 (75.4%; 90% CI, 64.3% to 84.5%) of 57 in the ABVD arm. The 2-year progression-free survival (PFS) was 97.3% (95% CI, 91.9 to 99.1) and 92.6% (95% CI, 81.4% to 97.2%) in the BV-AVD and ABVD arms, respectively. High total metabolic tumor volume was associated with a significantly shorter PFS (hazard ratio, 17.9; 95% CI, 2.2 to 145.5; P < .001). For patients with high total metabolic tumor volume, the 2-year PFS rate was 90.9% (95% CI, 74.4 to 97.0) and 70.7% (95% CI, 39.4% to 87.9%) in the BV-AVD and ABVD arms, respectively.

CONCLUSION

BV-AVD demonstrated an improvement in the PET-negative rate compared with ABVD after two cycles.

Imaging evaluation of lymphoma in pregnancy with review of clinical assessment and treatment options

Lymphoma-related malignancies can be categorized as Hodgkin's lymphoma (HL) or non-Hodgkin's lymphoma (NHL) based on histologic characteristics. Although quite rare during pregnancy, HL and NHL are the fourth and fifth most common malignancies during the pregnancy period, respectively. Given the rarity of lymphoma among pregnant patients, radiologists are usually unfamiliar with the modifications required for staging and treatment of this population, even those who work at centers with busy obstetrical services. Therefore, this manuscript serves to not only review the abdominopelvic imaging features of lymphoma in pregnancy, but it also discusses topics including birthing parent and fetal lymphoma-related prognosis, both antenatal and postpartum, current concepts in the management of pregnancy-related lymphoma, as well as the current considerations regarding birthing parent onco-fertility.

Repeatability of metabolic tumor burden and lesion glycolysis between clinical readers

The Metabolic Tumor Volume (MTV) and Tumor Lesion Glycolysis (TLG) has been shown to be independent prognostic predictors for clinical outcome in Diffuse Large B-cell Lymphoma (DLBCL). However, definitions of these measurements have not been standardized, leading to many sources of variation, operator evaluation continues to be one major source. In this study, we propose a reader reproducibility study to evaluate computation of TMV (& TLG) metrics based on differences in lesion delineation. In the first approach, reader manually corrected regional boundaries after automated detection performed across the lesions in a body scan (Reader M using a manual process, or manual). The other reader used a semi-automated method of lesion identification, without any boundary modification (Reader A using a semi- automated process, or auto). Parameters for active lesion were kept the same, derived from standard uptake values (SUVs) over a 41% threshold. We systematically contrasted MTV & TLG differences between expert readers (Reader M & A). We find that MTVs computed by Readers M and A were both concordant between them (concordant correlation coefficient of 0.96) and independently prognostic with a P-value of 0.0001 and 0.0002 respectively for overall survival after treatment. Additionally, we find TLG for these reader approaches showed concordance (CCC of 0.96) and was prognostic for over -all survival (p ≤ 0.0001 for both). In conclusion, the semi-automated approach (Reader A) provides acceptable quantification & prognosis of tumor burden (MTV) and TLG in comparison to expert reader assisted measurement (Reader M) on PET/CT scans.

A retrospective study of 18 children with subcutaneous panniculitis-like T-cell lymphoma: multidrug combination chemotherapy or immunomodulatory therapy?

BACKGROUND

Subcutaneous panniculitis T-cell lymphoma (SPTCL) is a rare, cytotoxic T-cell lymphoma with which some patients have accompanying hemophagocytic syndrome (HPS). There is currently no standard treatment regimen. In the past, the most commonly used treatment was multidrug chemotherapy. In contrast, numerous case reports or small series suggest that immunosuppressive drugs could also be effective for some patients. Since this NHL subtype is extremely rare in children and adolescents, to improve the understanding of this disease and standardize its rational treatment, we retrospectively summarized the treatment regimens of 18 pathologically diagnosed children with SPTCL to compare the clinical efficacy of multidrug chemotherapy and immunomodulatory therapy.

RESULTS

The median age of onset was 11.1 years. Painless subcutaneous nodules or skin patchy lesions were found in all patients, most commonly involving the lower extremities and/or trunk. Before January 1, 2019, the treatment was mainly chemotherapy, and 10 patients were initially treated with chemotherapy, among whom was one patient who progressed during initial treatment, was voluntarily discharged and was subsequently lost to follow-up, one patient who died of disease progression, and the remaining 8 patients who all achieved sustained remission, with a complete remission (CR) rate of 80% (8/10). Corticosteroids combined with cyclosporine A or ruxolitinib were the most common initial immunosuppressive agents at our center after January 1, 2019 and had a CR rate of 71.4% (5/7). In addition, 1 patient achieved partial remission (PR) during follow-up, and one had autologous hematopoietic stem cell transplantation (AHSCT) after 4 months of drug withdrawal. There were 7 patients (38.9%, one case in chemotherapy group and six cases in immunotherapy group) with HPS and 4/5 screened patients (80%) with positive HAVCR2 gene mutations. The median follow-up was 17 months.

CONCLUSION

The prognosis of SPTCL is relatively good. Previous multi-drug and long-term chemotherapy treatment has clear efficacy, and recent immunomodulatory therapy as pre-chemotherapy therapy can also benefit patients.

Do all patients with primary refractory/first relapse of HL need autologous stem cell transplant?

The standard approach to treatment of primary refractory/first relapse of classical Hodgkin lymphoma (cHL) is administration of second-line therapy (SLT) followed by consolidation with high-dose therapy and autologous hematopoietic cell transplantation (HDT/AHCT). Historically, this approach cured about 50% of patients. Due to improvements in supportive care, positron emission tomography-adaptive strategies, and incorporation of novel agents into SLT, contemporary studies show that about 75% of patients with primary refractory or first relapse of cHL can be cured. Recent studies evaluating incorporation of PD-1 blockade in SLT appear to show even further improvement in remission rates and bring into question whether an aggressive approach that includes HDT/AHCT is needed for everyone. To address this question, several ongoing studies are beginning to explore the possibility of avoiding or delaying HDT/AHCT for patients with primary refractory or first relapse of cHL.

PET-CR as a potential surrogate endpoint in untreated DLBCL: meta-analysis and implications for clinical trial design

This study's focus is the association of end-of-therapy (EOT) PET results with progression-free (PFS) and overall survival (OS) in patients with diffuse large B-cell lymphoma receiving first-line chemoimmunotherapy. We develop a Bayesian hierarchical model for predicting PFS and OS from EOT PET-complete response (PET-CR) using a literature-based meta-analysis of 20 treatment arms and a substudy of 4 treatment arms in 3 clinical trials for which we have patient-level data. The PET-CR rate in our substudy was 72%. The modeled estimates for hazard ratio (PET-CR/non-PET-CR) were 0.13 for PFS (95% CI 0.10, 0.16) and 0.10 for OS (CI 0.07, 0.12). Hazard ratios varied little by patient subtype and were confirmed by the overall meta-analysis. We link these findings to designing future clinical trials and show how our model can be used in adapting the sample size of a trial to accumulating results regarding treatment benefits on PET-CR and a survival endpoint.

Comparison between diffusion-weighted magnetic resonance and positron-emission tomography in the evaluation of treated lymphomas with mediastinal involvement

Background

The persistence of residual tissue after treatment is frequent in patients with mediastinal lymphomas and it is often characterized by 18F-Flurodeoxyglucose Positron Emission Tomography (18F-FDG PET) uptake. This study aims to investigate the usefulness of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) sequence in residual tissues of treated mediastinal lymphomas and to compare it with 18F-FDG PET-CT.

Results

We included 21 patients with mediastinal Hodgkin and non-Hodgkin lymphomas who showed residual masses on PET-CT imaging at end of treatment and underwent DWIBS-Magnetic Resonance Imaging (MRI). SUVmax and Apparent Diffusion Coefficient (ADC) values of residual masses were assessed quantitatively, including measurement of mean ADC. 15 patients showed radiotracer uptake at 18F-FDG PET-CT, among them only 3 had positive DWIBS-MRI with low ADC values (median value: 0.90 mm2/s). The mediastinal biopsy in these 3 “double positive” patients confirmed pathological residual tissue. All the patients with positive 18F-FDG PET-CT but negative DWIBS-MRI (n = 18) with high ADC values (median value: 2.05 mm2/s) were confirmed negative by biopsy.

Conclusions

DWIBS-MRI examination combined with ADC measurement allowed to discriminate pathological and non-pathological residual tissue in patients with treated mediastinal lymphoma. These preliminary results seem to pave the way for a leading role of the MRI which could be a useful alternative to the 18F-FDG PET/CT.