Hodgkin lymphoma: Response assessment by Revised International Workshop Criteria

FDG-PET/CT for the Management of Post-Chemotherapy Residual Mass in Hodgkin lymphoma

Simple Summary

In the present review the authors report the predictive value of FDG/PET-CT (PET) on treatment outcome of Hodgkin lymphoma patients showing a post-chemotherapy residual mass, based on the published reports of PET-guided consolidation radiotherapy after different-intensity chemotherapy regimens such as ABVD or BEACOPP_escalated. A special focus will be dedicated to the role of PET for assessing patients with a residual mass during and after immunotherapy with immune checkpoint inhibitors. Finally, the interpretation criteria of PET will be also reviewed, and the role of alternative imaging techniques discussed.

Abstract

In the present review, the authors report the published evidence on the use of functional imaging with FDG-PET/CT in assessing the final response to treatment in Hodgkin lymphoma. Despite a very high overall Negative Predictive Value of post-chemotherapy PET on treatment outcome ranging from 94% to 86%, according to different treatment intensity, the Positive Predicting Value proved much lower (40–25%). In the present review the Authors discuss the role of PET to guide consolidation RT over a RM after different chemotherapy regimens, both in early and in advanced-stage disease. A particular emphasis is dedicated to the peculiar issue of the qualitative versus semi-quantitative methods for End-of Therapy PET scan interpretation. A short hint will be given on the role of FDG-PET to assess the treatment outcome after immune checkpoint inhibitors.

Consolidation Radiotherapy Could Be Safely Omitted in Advanced Hodgkin Lymphoma With Large Nodal Mass in Complete Metabolic Response After ABVD: Final Analysis of the Randomized GITIL/FIL HD0607 Trial

PURPOSE

To investigate the role of consolidation radiotherapy (cRT) in advanced-stage Hodgkin lymphoma (HL) presenting at baseline with a large nodal mass (LNM) in complete metabolic response after doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) chemotherapy.

PATIENTS AND METHODS

Advanced-stage (IIB-IVB) HL patients, enrolled in the HD 0607 trial (Clinicaltrial.gov identifier NCT00795613), with both a negative PET after two (PET-2) and six (PET-6) ABVD cycles, who presented at baseline with an LNM, defined as a nodal mass with the largest diameter ≥ 5 cm, were prospectively randomly assigned to receive cRT over the LNM or no further treatment (NFT).

RESULTS

Among 296 randomly assigned patients, the largest diameter of LNM at baseline was 5-7 cm in 101 (34%; subgroup A) and 8-10 cm in 96 (32%; subgroup B), whereas classic bulky (diameter > 10 cm) was detected in 99 (33%; subgroup C). Two hundred eighty patients (88%) showed a postchemotherapy RM. The median dose of cRT was 30.6 Gy (range, 24-36 Gy). After a median follow-up of 5.9 years (range, 0.5-10 years), the 6-year progression-free survival rate of patients who underwent cRT or NFT was, respectively, 91% (95% CI, 84% to 99%) and 95% (95% CI, 89% to 100%; P = .62) in subgroup A; 98% (95% CI, 93% to 100%) and 90% (95% CI, 80% to 100%; P = .24) in subgroup B; 89% (95% CI, 81% to 98%) and 86% (95% CI, 77% to 96%; P = .53) in subgroup C (classic bulky).

CONCLUSION

cRT could be safely omitted in patients with HL presenting with an LNM and a negative PET-2 and PET-6 scan, irrespective from the LNM size detected at baseline.

Improvements in Imaging of Hodgkin Lymphoma: Positron Emission Tomography

18-Fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET/CT) is currently the criterion standard of lymphoma imaging and recommended through all stages of Hodgkin lymphoma management. Accurate staging is important for risk stratification and initial choice of therapy and also for the planning of postchemoradiotherapy. 18-Fluoro-2-deoxy-D-glucose PET/CT frequently leads to upstaging and potentially a more intensive treatment. Visual-only assessment of staging and interim scans is being accompanied by quantitative and semiquantitative methods to measure metabolic tumor volume, total lesion glycolysis, and so on. It is still unclear if these methods significantly improve the value of FDG PET/CT by visual assessment only. Because of the good prognostic value of FDG PET/CT, a large number of studies have used interim FDG PET to tailor treatment to the individual patients, according to their early metabolic response rather than according to their pretreatment prognostic features. 18-Fluoro-2-deoxy-D-glucose PET/CT is standard of care for posttreatment response assessment but has no place in routine follow-up of Hodgkin lymphoma patients in remission.

The role of PET/CT in the modern treatment of Hodgkin lymphoma

Classical Hodgkin Lymphoma is distinguished from other lymphomas by its peculiar biology and heterogeneous chemosensitivity. Most of the patients respond to the standard first-line treatment and are cured, however, in selected cases, the disease relapses or remains primarily refractory. Among predictive/prognostic factors ¹⁸FDG positron emission tomography (PET), fully integrated with computed tomography (PET/CT) proved to be extremely useful in identifying patients with poor prognosis at the time of diagnosis, during and at the end of treatment. The aim of this review is to present the current role of PET/CT in cHL at staging, interim and end of therapy assessment and its ability to guide treatment with a response- and risk-adapted strategy in clinical practice. Finally, quantitative PET measurement and the concurrent use of PET with selected biomarkers are discussed.

Molecular Imaging and Precision Medicine: PET/Computed Tomography and Therapy Response Assessment in Oncology

A variety of methods have been developed to assess tumor response to therapy. Standardized qualitative criteria based on 18F-fluoro-deoxyglucose PET/computed tomography have been proposed to evaluate the treatment effectiveness in specific cancers and these allow more accurate therapy response assessment and survival prognostication. Multiple studies have addressed the utility of the volumetric PET biomarkers as prognostic indicators but there is no consensus about the preferred segmentation methodology for these metrics. Heterogeneous intratumoral uptake was proposed as a novel PET metric for therapy response assessment. PET imaging techniques will be used to study the biological behavior of cancers during therapy.

Hybrid FDG-PET/MR compared to FDG-PET/CT in adult lymphoma patients

PURPOSE

The goal of this study is to evaluate the diagnostic performance of simultaneous FDG-PET/MR including diffusion compared to FDG-PET/CT in patients with lymphoma.

METHODS

Eighteen patients with a confirmed diagnosis of non-Hodgkin's (NHL) or Hodgkin's lymphoma (HL) underwent an IRB-approved, single-injection/dual-imaging protocol consisting of a clinical FDG-PET/CT and subsequent FDG-PET/MR scan. PET images from both modalities were reconstructed iteratively. Attenuation correction was performed using low-dose CT data for PET/CT and Dixon-MR sequences for PET/MR. Diffusion-weighted imaging was performed. SUVmax was measured and compared between modalities and the apparent diffusion coefficient (ADC) using ROI analysis by an experienced radiologist using OsiriX. Strength of correlation between variables was measured using the Pearson correlation coefficient (r p).

RESULTS

Of the 18 patients included in this study, 5 had HL and 13 had NHL. The median age was 51 ± 14.8 years. Sixty-five FDG-avid lesions were identified. All FDG-avid lesions were visible with comparable contrast, and therefore initial and follow-up staging was identical between both examinations. SUVmax from FDG-PET/MR [(mean ± sem) (21.3 ± 2.07)] vs. FDG-PET/CT (mean 23.2 ± 2.8) demonstrated a strongly positive correlation [r s = 0.95 (0.94, 0.99); p < 0.0001]. There was no correlation found between ADCmin and SUVmax from FDG-PET/MR [r = 0.17(-0.07, 0.66); p = 0.09].

CONCLUSION

FDG-PET/MR offers an equivalent whole-body staging examination as compared with PET/CT with an improved radiation safety profile in lymphoma patients. Correlation of ADC to SUVmax was weak, understating their lack of equivalence, but not undermining their potential synergy and differing importance.

Response Assessment Criteria and Their Applications in Lymphoma: Part 1

The effectiveness of cancer therapy, both in individual patients and across populations, requires a systematic and reproducible method for evaluating response to treatment. Early efforts to meet this need resulted in the creation of numerous guidelines for quantifying posttherapy changes in disease extent, both anatomically and metabolically. Over the past few years, criteria for disease response classification have been developed for specific cancer histologies. To date, the spectrum of disease broadly referred to as lymphoma is perhaps the most common for which disease response classification is used. This review article provides an overview of the existing response assessment criteria for lymphoma and highlights their respective methodologies and validities. Concerns over the technical complexity and arbitrary thresholds of many of these criteria, which have impeded the long-standing endeavor of standardizing response assessment, are also discussed.

No survival benefit associated with routine surveillance imaging for Hodgkin lymphoma in first remission: a Danish-Swedish population-based observational study

The use of routine imaging for patients with classical Hodgkin lymphoma (HL) in complete remission (CR) is controversial. In a population-based study, we examined the post-remission survival of Danish and Swedish HL patients for whom follow-up practices were different. Follow-up in Denmark included routine imaging, usually for a minimum of 2 years, whereas clinical follow-up without routine imaging was standard in Sweden. A total of 317 Danish and 454 Swedish comparable HL patients aged 18-65 years, diagnosed in the period 2007-2012 and having achieved CR following ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine)/BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone) therapy, were included in the study. The cumulative progression rates in the first 2 years were 4% (95% confidence interval [CI] 1-7) for patients with stage I-II disease vs. 12% (95% CI 6-18) for patients with stage III-IV disease. An imaging-based follow-up practice was not associated with a better post-remission survival in general (P = 0·2) or in stage-specific subgroups (P = 0·5 for I-II and P = 0·4 for III-IV). Age ≥45 years was the only independent adverse prognostic factor for survival. In conclusion, relapse of HL patients with CR is infrequent and systematic use of routine imaging in these patients does not improve post-remission survival. The present study supports clinical follow-up without routine imaging, as encouraged by the recent Lugano classification.

Utility of interim and end-of-treatment PET/CT in peripheral T-cell lymphomas: A review of 124 patients

According to the updated guidelines for imaging in lymphoma, 18F-FDG positron emission tomography/computed tomography (PET/CT) is recommended for staging and evaluation of treatment response in FDG-avid lymphomas. The purpose of the study was to evaluate the utility of PET/CT in nodal peripheral T-cell lymphomas (PTCL). Patients with newly diagnosed nodal PTCL (peripheral T-cell lymphoma NOS, anaplastic large-cell lymphoma, or angioimmunoblastic T-cell lymphoma) seen at five Danish hematology centers during the period 2006 to 2012 were included, if they had been pretherapeutically staged with PET/CT. Medical records were reviewed for baseline clinical and follow-up information. Staging, interim (I-PET), and end-of-treatment PET/CT (E-PET) studies were centrally reviewed, and reported using the Deauville 5-point score (DS). A total of 124 patients fulfilled the inclusion criteria. The median age was 58 years, and 88% received CHOP/CHOP-like therapy. Five years PFS and OS of the study population was 36.8% (95% CI 27.3-46.4) and 49.7% (95% CI 38.9-59.6), respectively. The presence of PET/CT-ascertained lung and/or liver involvement was associated with a worse outcome. The sensitivity of PET/CT for detecting biopsy-defined bone marrow involvement was only 18% (95% CI 4-43). An interim DS >3 was not prognostic for worse OS and PFS among CHOP/CHOP-like treated patients in uni- or multivariate analyses. A DS >3 after treatment predicted a worse prognosis. In conclusion, I-PET was not predictive of outcome in CHOP/CHOP-like treated PTCL patients when using the DS. Prospective studies are needed to determine the optimal use of PET/CT in PTCL including the role of quantitative PET/CT analysis.

FDG PET/CT Response Assessment Criteria for Patients with Hodgkin's and Non-Hodgkin's Lymphoma at End of Therapy: A Multiparametric Approach

PURPOSE

Based on the International Harmonization Project (IHP) criteria, positron emission tomography (PET) response assessment of residual nodal masses in patients with lymphoma after completion of therapy is performed visually using mediastinal blood pool as the reference. The primary objective of this study was to define the optimal reference for PET response assessment. Secondary aim was to assess if morphological criteria on computed tomography (CT) may improve performance of PET.

METHODS

This institutional review board approved retrospective study included 137 patients, with Hodgkin's (n = 43) or non-Hodgkin's lymphoma (n = 94) assessed for residual masses (n = 180) after completion of therapy with pathology and clinical and imaging surveillance data (mean, 19 months) as the standard of reference. Two readers independently assessed response by IHP and Deauville criteria. The addition of morphological parameters on CT was assessed in relation to therapy response.

RESULTS

Based on the standard of reference, 36 patients (26.3 %) had residual lymphoma. For IHP and Deauville criteria, sensitivity, specificity and accuracy were 97.2 %, 97.2 % (p = 1); 79.2 %, 92.1 % (p < 0.001); and 83.9 %, 93.4 % (p = 0.001), respectively. Of the morphological parameters assessed, only change in size over course of therapy was significant (p < 0.003) and improved specificity for IHP-based interpretation to 90.4 % (p = 0.008).

CONCLUSIONS

Using liver as the visual reference to determine PET positivity for lymphoma patients being assessed for residual masses at the end of therapy improves specificity, yet maintains the high sensitivity of PET in identifying residual disease. The addition of change in size after therapy improves specificity of PET when using IHP-based but not Deauville-based interpretation.

Imbalance of Pro- and Anti-Inflammatory Cytokines in Patients With cHL Persists Despite Treatment Compared With Control Subjects

BACKGROUND

Classical Hodgkin lymphoma (cHL) is a malignant lymphoma that most commonly affects young adults. The lymphomagenesis of cHL depends largely on immune alterations that contribute to proliferation and maintenance of the Hodgkin-Reed-Sternberg (HRS) neoplastic cells. A combination of different immune processes is responsible for the escape of HRS cells, the imbalance between pro- and anti-inflammatory cytokines being one of them. In this study, we aimed to measure serum levels of pro- and anti-inflammatory cytokines in cHL patients before and after treatment compared with a healthy controls group, and to investigate associations with clinical and pathologic characteristics.

PATIENTS AND METHODS

We prospectively studied all cases of cHL diagnosed between March 2009 to March 2013 at the Universidade Federal de São Paulo and Hospital Santa Marcelina, in Sao Paulo, Brazil. Twenty-nine cases with sufficient clinical data were included in this study. Additionally, 18 healthy control subjects were included and recruited from our University Blood Bank. Serum cytokine levels of interleukin (IL)-2, IL-4, IL-5, IL-6, IL-10, IL-17, tumor necrosis factor (TNF)-α, soluble IL-2 receptor (sCD25), vascular endothelial growth factor (VEGF), and interferon (IFN)-γ were determined in serum of patients and controls using a multiplexed immunoassay system.

RESULTS

Higher International Prognostic Score was positively correlated with increased levels of IL-6 (P = .003); sCD25 levels were higher in patients with low serum albumin (P = .04), and IFN-γ seemed to correlate with B symptoms, although did not reach statistical significance (P = .057). Pretreatment levels of IL-10, IL-6, TNF-α, and sCD25 were increased in cHL patients compared with in healthy control subjects (P < .001), with median values of 7 pg/mL (range, 0.3-230.9), 5.3 pg/mL (range, 0.4-72.7), 14.6 (range, 4.0-60.4), and 575.9 pg/mL (range, 7.5-1813.3), respectively. Treatment significantly reduced levels of IL-10 (7.0 to 0.3; P < .001), IL-6 (5.3 to 0.4; P = .014), and sCD25 (575.9 to 93.5; P < .001), however, levels of IL-4 increased (0.6 to 2.2; P = .002). Compared with normal control subjects, increased levels of IL-6 (0.4 to 0.4; P = .027), sCD25 (93.5 to 7.5; P = .002), and TNF-α (12 to 8.7; P = .003) persisted after treatment.

CONCLUSION

In this study we showed higher levels of IL-6, IL-10, TNF-α, and sCD25 in cHL patients at diagnosis than in healthy control subjects. After treatment, levels of IL-6, IL-10, and sCD25 decreased gradually but did not normalize. Understanding the cytokine pattern is extremely important in the development of future therapies that target interactions between neoplastic cells and the inflammatory microenvironment.

Response criteria for malignant lymphoma

In the last 35 years, many attempts have been made to define criteria for the assessment of treatment response in malignant lymphoma. These systems, with respect to both morphological and molecular imaging, aim to standardize scan results, in order to simplify the interpretation of findings, facilitate multicentric research trials, and compare published data. Unfortunately, there is no consensus among the main international hematological associations on which criteria are the most appropriate. This detailed and comprehensive description of all classifications intends to focus attention on this topic.

Current role of FDG PET/CT in lymphoma

The management approach in Hodgkin's (HL) and high-grade non-Hodgkin's lymphomas (NHL) has shifted towards reducing the toxicity and long-term adverse effects associated with treatment while maintaining favorable outcomes in low-risk patients. The success of an individualized treatment strategy depends largely on accurate diagnostic tests both at staging and during therapy. In this regard, positron emission tomography (PET) using fluorodeoxyglucose (FDG) with computed tomography (CT) has proved effective as a metabolic imaging tool with compelling evidence supporting its superiority over conventional modalities, particularly in staging and early evaluation of response. Eventually, this modality was integrated into the routine staging and restaging algorithm of lymphomas. This review will summarize the data on the proven and potential utility of PET/CT imaging for staging, response assessment, and restaging, describing current limitations of this imaging modality.

Clinical translation of molecular imaging agents used in PET studies of cancer

Over recent years, there has been a rapid expansion in our knowledge of the factors that regulate tumor growth; this has resulted in the identification of new therapeutic targets and improvements in the long-term survival of cancer patients. New noninvasive biomarkers of drug targets and pathway modulation in vivo are needed to guide therapy selection and detect drug resistance early so that alternative, more effective treatments can be offered. The translation of new therapeutics into the clinic is disappointingly slow, expensive, and subject to high rates of attrition often occurring at late stages (phase 3) of development. In an attempt to mitigate these delays and failures, there has been resurgence in the development of new molecular imaging probes for studies with positron emission tomography (PET) to characterize tumor biology. In the assessment of therapeutic effects, PET allows imaging of entire tumor burden in a noninvasive repeatable manner. This chapter focuses on the clinical translation of PET imaging agents from bench to bedside. New probes are being used to study a diverse range of processes such as angiogenesis, apoptosis, fatty acid metabolism, and growth factor receptor expression. In the future, validation of these novel imaging probes could allow more innovative therapies to be adapted earlier in the clinic leading to improved patient outcomes.

Current status of PET/CT in the diagnosis and follow up of lymphomas

Lymphomas are a heterogeneous group of malignancies that have a distinct biological behavior according to the subtype and degree of differentiation. Adequate staging, which has a direct impact on prognosis, is essential to properly plan therapy. Structural cross-sectional imaging, such as computed tomography, has been the standard imaging tool to stage and monitor patients with lymphoma. However, molecular imaging such as positron emission tomography has shown complementary diagnostic and prognostic values. This review discusses the current value of positron emission tomography imaging using 2-[fluorine-18]fluoro-2-deoxy-d-glucose in staging, restaging, monitoring and detecting relapse in Hodgkin's and non-Hodgkin lymphoma.

Scaling up cancer care for children without medical insurance in developing countries: The case of Mexico

BACKGROUND

In 2006, the Mexican government launched the Fund for Protection Against Catastrophic Expenditures (FPGC) to support financially healthcare of high cost illnesses. This study aimed at answering the question whether FPGC improved coverage for cancer care and to measure survival of FPGC affiliated children with cancer.

PROCEDURE

A retrospective cohort study (2006-2009) was conducted in 47 public hospitals. Information of children and adolescents with cancer was analyzed. The coverage was estimated in accordance with expected number of incident cases and those registered at FPGC. The survival was analyzed by using Kaplan-Meier survival curves and Cox proportional hazards regression modeling.

RESULTS

The study included 3,821 patients. From 2006 to 2009, coverage of new cancer cases increased from 3.3% to 55.3%. Principal diagnoses were acute lymphoblastic leukemia (ALL, 46.4%), central nervous system (CNS) tumors (8.2%), and acute myeloid leukemia (AML, 7.4%). The survival rates at 36 months were ALL (50%), AML (30.5%), Hodgkin lymphoma (74.5%), Non-Hodgkin lymphoma (40.1%), CNS tumors (32.8%), renal tumors (58.4%), bone tumors (33.4%), retinoblastoma (59.2%), and other solid tumors (52.6%). The 3-year overall survival rates varied among the regions; children between the east and south-southeast had the higher risks (hazard ratio 3.0; 95% CI: 2.3-3.9) and 2.4; 95% CI: 2.0-2.8) of death from disease when compared with those from the central region.

CONCLUSION

FPGC has increased coverage of cancer cases. Survival rates were different throughout the country. It is necessary to evaluate the effectiveness of this policy to increase access and identify opportunities to reduce the differences in survival.

The role of FDG-PET scanning in assessing lymphoma in 2012

Positron emission tomography (PET) has a proven role in the assessment diffuse large B-cell lymphoma (DLBCL) and Hodgkin's lymphoma (HL). The clinical impact of PET carried out at the end of the patient's course of treatment is undeniable and recommendations must be followed in the interpretation of these examinations. PET is highly recommended as part of the initial investigations of these diseases because it can be used as a reference for the interpretation at treatment completion and allows disease spread to be assessed with greater sensitivity and specificity than when computed tomography (CT) is used. It seems to be certain that PET is useful for interim examinations too, in terms of assessing prognosis in DLBCL and HL, although its impact in terms of early changes to treatment is still to be determined. The criteria for interpreting the results of these early assessments are still evolving and the annual meetings in Menton, France, of groups of experts are leading towards a uniform interpretation method. In other types of lymphoma, PET can be useful for confirming local disease staging, especially in follicular lymphoma, and for guiding biopsy in patients with low-grade lymphoma that is suspicious for transformation into more aggressive disease. Several studies are in agreement that PET is valuable for assessing prognosis at treatment completion in FL and mantle cell lymphoma, but prospective studies are needed for this new indication to be validated.

How does PET/CT help in selecting therapy for patients with Hodgkin lymphoma?

Positron emission tomography/computed tomography (PET/CT) has emerged as the most accurate tool for staging, treatment monitoring, and response evaluation in Hodgkin lymphoma (HL). Accurate staging and restaging are very important for the optimal management of HL, but we are only beginning to understand how to use PET/CT to improve treatment outcome. More precise determination of disease extent may result in more precise pretreatment risk stratification, and is also essential for the minimal and highly individualized radiotherapy volumes of the present era. Several trials are currently investigating the use of PET/CT for early response-adapted therapy, with therapeutic stratification based on interim PET/CT results. Posttreatment PET/CT is a cornerstone of the revised response criteria and enables the selection of advanced-stage patients without the need for consolidation radiotherapy. Once remission is achieved after first-line therapy, PET/CT seems to have little or no role in the routine surveillance of HL patients. PET/CT looks promising for the selection of therapy in relapsed and refractory disease, but its role in this setting is still unclear.

Comparison of various criteria in interpreting end of therapy F-18 labeled fluorodeoxyglucose positron emission tomography/computed tomography in patients with aggressive non-Hodgkin lymphoma

Various interpretation criteria exist to assess end of therapy F-18 labeled fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in lymphoma. This study was carried out to compare these criteria. Data of 69 patients with aggressive non-Hodgkin lymphoma (AGR-NHL) who underwent FDG PET/CT at the end of therapy and were followed up for a minimum period of 1 year (median follow-up period 17 months) were evaluated. Twenty-eight of the 69 patients were found to have residual/recurrent disease during follow-up. The accuracy for predicting residual disease of International Harmonization Project (IHP) criteria, London criteria and Gallamini criteria was 71.0%, 84.0% and 88.4%, respectively. Gallamini and London criteria had greater accuracies in predicting residual disease than IHP criteria (p = 0.0001). The major difference in accuracy was due to the low positive predictive value of IHP criteria. Positive predictive values (PPVs) of both London and Gallamini criteria (79.3% and 88.5%, respectively) were high when compared with that of IHP criteria (60.5%) (p = 0.001). Negative predictive values (NPVs) were similar for all the criteria. In conclusion, Gallamini and London criteria had higher accuracy when interpreting end of therapy FDG PET/CT studies in AGR-NHL. London criteria can be used preferentially over Gallamini criteria because of simplicity in interpretation and reproducibility.

Increased expression of CD4+CD25 +FOXP3+ regulatory T cells correlates with Epstein-Barr virus and has no impact on survival in patients with classical Hodgkin lymphoma in Brazil

The tumor microenvironment of classical Hodgkin lymphoma (cHL) is clearly responsible for the maintenance of the malignant Hodgkin-Reed-Sternberg (HRS) cells, and Epstein-Barr virus (EBV) has been shown to play a role in this immune evasion. EBV can increase the migration of CD4(+)CD25(+)FOXP3(+) lymphocytes, named regulatory T cells (Tregs). In this study, we assessed the distribution and biological significance of Tregs in patients with cHL. Tissue microarrays were constructed using diagnostic biopsies available in 130 cHL patients and stained with CD4, CD8, CD25, and FOXP3 antibodies. For the present study, only cHL patients whose histology could be confirmed and EBV association established were studied. From the 130 cHL patients selected for this study, 56 were classified as EBV-related and 74 EBV non-related cHL. There were no association between clinical characteristics and the expression of Tregs. However, higher levels of Tregs correlated with EBV presence on HRS cells (p = 0.02), although it did not influence event-free survival (EFS) and overall survival (p = 0.98 and p = 0.59, respectively). This study demonstrates that Tregs expression correlates with EBV presence in HRS cells and has no impact on survival of patients with cHL. Further studies investigating the mechanisms in which EBV recruits Tregs to the tumor microenvironment will contribute not only to our understanding on the pathogenesis of cHL but also to the development of new therapeutic strategies.

[Quantitative and qualitative evaluation of the interim PET/CT in lymphoma treatment in the prediction of complete metabolic response]

OBJECTIVE

To compare two different methods for the interpretation of interim PET/CT (PET/CT-i) in lymphomas, and to establish which one best predicts a complete metabolic response (CMR) in the PET/CT study at the end of treatment (PET/CT-et).

MATERIAL AND METHODS

Retrospective longitudinal analysis of the PET/CT studies for staging (PET/CT-s), PET/CT-i and PET/CT-et of 65 patients, 35 Hodgkin's lymphoma (HL) and 30 Non-HL. The PET/CT-i was performed between the second and fourth chemotherapy cycle. It was interpreted using two different criteria: qualitative criteria (5 point visual scale), semiquantitative criteria (percentage difference between the lesion with more SUVmax in the PET/CT-s and PET/CT-i). We analyzed the likelihood of obtaining a CMR in the PET/CT-et according to the results obtained on the PET/CT-i with these two criteria.

RESULTS

We obtained sensitivity (S), specificity (Sp), positive predictive values (PPV), negative predictive values (NPV) and likelihood ratio (LR) for the qualitative/semiquantitative method of 91%/80%, 76.2%/67%, 88.9%/83.3%, 80%/60.9% and 32%/7.8%, respectively, to predict a CMR in the PET/CT-et. There were no statistically significant differences between the LR of both methods (p=0.1942).

CONCLUSION

We found clear differences in S, Sp, PPV and NPV between both interpretation criteria for the PET/CT-i to predict a CMR in the PET/CT-et. Nevertheless, we cannot confirm the superiority of the qualitative method over the semiqualitative method for this purpose as no statistically significance differences were found in their LR in our study.

Association between radiotherapy vs no radiotherapy based on early response to VAMP chemotherapy and survival among children with favorable-risk Hodgkin lymphoma

CONTEXT

More than 90% of children with favorable-risk Hodgkin lymphoma can achieve long-term survival, yet many will experience toxic effects from radiation therapy. Pediatric oncologists strive for maintaining excellent cure rates while minimizing toxic effects.

OBJECTIVE

To evaluate the efficacy of 4 cycles of vinblastine, Adriamycin (doxorubicin), methotrexate, and prednisone (VAMP) in patients with favorable-risk Hodgkin lymphoma who achieve a complete response after 2 cycles and do not receive radiotherapy.

DESIGN, SETTING, AND PATIENTS

Multi-institutional, unblinded, nonrandomized single group phase 2 clinical trial to assess the need for radiotherapy based on early response to chemotherapy. Eighty-eight eligible patients with Hodgkin lymphoma stage I and II (<3 nodal sites, no B symptoms, mediastinal bulk, or extranodal extension) enrolled between March 3, 2000, and December 9, 2008. Follow-up data are current to March 12, 2012.

INTERVENTIONS

The 47 patients who achieved a complete response after 2 cycles received no radiotherapy, and the 41 with less than a complete response were given 25.5 Gy-involved-field radiotherapy.

MAIN OUTCOME MEASURES

Two-year event-free survival was the primary outcome measure. A 2-year event-free survival of greater than 90% was desired, and 80% was considered to be unacceptably low.

RESULTS

Two-year event-free survival was 90.8% (95% CI, 84.7%-96.9%). For patients who did not require radiotherapy, it was 89.4% (95% CI, 80.8%-98.0%) compared with 92.5% (95% CI, 84.5%-100%) for those who did (P = .61). Most common acute adverse effects were neuropathic pain (2% of patients), nausea or vomiting (3% of patients), neutropenia (32% of cycles), and febrile neutropenia (2% of patients). Nine patients (10%) were hospitalized 11 times (3% of cycles) for febrile neutropenia or nonneutropenic infection. Long-term adverse effects after radiotherapy were asymptomatic compensated hypothyroidism in 9 patients (10%), osteonecrosis and moderate osteopenia in 2 patients each (2%), subclinical pulmonary dysfunction in 12 patients (14%), and asymptomatic left ventricular dysfunction in 4 patients (5%). No second malignant neoplasms were observed.

CONCLUSIONS

Among patients with favorable-risk Hodgkin lymphoma and a complete early response to chemotherapy, the use of limited radiotherapy resulted in a high rate of 2-year event-free survival.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00145600.

Impact of FDG-PET/CT in the management of lymphoma

Since the introduction of (67)Gallium-citrate 30 years ago, nuclear medicine has played an important role in the evaluation of malignant lymphoma. During that time, several radiotracers were evaluated as potential alternatives for the diagnosis of lymphoma, but the introduction of (18)F-fluorodeoxyglucose PET (FDG-PET) marked a major turning point. FDG-PET took over most of the role of gallium, and is now an essential tool in the diagnosis of lymphoma. FDG-PET is increasingly being used for assessment of the tumor staging prior to treatment, for evaluating the response to treatment, and for monitoring the early reactions to therapy to predict the final outcome. FDG-PET has been shown to have more accurate diagnostic capability than conventional CT and MRI for distinguishing the tumor necrosis and residual masses frequently seen after therapy in lymphoma patients without any clinical and biochemical manifestation. Malignant lymphoma is the first disease for which FDG-PET was adopted as a tool for response assessment in the international standard criteria. However, lymphoma does not always display a clear high uptake, and there are some pitfalls in assessing the response to therapy. This review will highlight the most important applications of FDG-PET in lymphoma, focusing on the advantages and pitfalls of this imaging, and past and ongoing efforts to standardize the use of FDG-PET, particularly in response to assessment and therapy monitoring.

An overview of cancer/testis antigens expression in classical Hodgkin's lymphoma (cHL) identifies MAGE-A family and MAGE-C1 as the most frequently expressed antigens in a set of Brazilian cHL patients

ABSTRACT: BACKGROUND: Cancer/testis antigens are considered potential targets for immunotherapy due to their tumor-associated expression pattern. Although recent studies have demonstrated high expression of CT45 in classical Hodgkin's lymphomas (cHL), less is known about the expression pattern of other families of CTAs in cHL. We aim to evaluate the expression of MAGE-A family, MAGE-C1/CT7, MAGE-C2/CT10, NY-ESO1 and GAGE family in cHL and to correlate their expression with clinical and prognostic factors in cHL. METHODS: Tissue microarray was generated from 38 cHL archival cases from Pathology Department of Universidade Federal de Sao Paulo. Immunohistochemistry (IHC) was done using the following panel of antibodies: MAGE-A family (MA454, M3H67, 57B and 6C1), GAGE (#26), NY-ESO-1 (E978), MAGE-C1/CT7 (CT7-33) and MAGE-C2/CT10 (CT10#5). RESULTS: We found CTA expression in 21.1% of our cHL series. Among the tested CTAs, only MAGE-A family 7/38 (18.4%) and MAGE-C1/CT7 5/38 (13.2%) were positive in our cHL samples. We found higher CTA positivity in advanced stage (28.6%) compared to early stage (11.8%) disease, but this difference was not statistically significant. Analysis of other clinicopathological subgroups of cHL including histological subtypes, EBV status and response to treatment also did not demonstrate statistical significant differences in CTA expression. CONCLUSION: We found CTA expression in 21.1% of cHL samples using our panel. Our preliminary findings suggest that from all CTAs included in this study, MAGE-A family and MAGE-C1/CT7 are the most interesting ones to be explored in further studies.

Dose-response relationship in cyclophosphamide-treated B-cell lymphoma xenografts monitored with [18F]FDG PET

PURPOSE

Although [(18)F]FDG PET can measure therapy response sooner and more accurately than morphological imaging techniques, there is still some debate as to whether [(18)F]FDG uptake really reflects changes in the viable cell fraction. In this study changes in [(18)F]FDG uptake were investigated in a lymphoma model at several time-points after treatment and with different doses of chemotherapy. Data were analysed in terms of several parameters.

METHODS

SCID mice were subcutaneously inoculated with 5x10(6) Daudi cells in the right thigh. One group was not treated (control group). The other groups received cyclophosphamide 75 mg/kg (low-dose group), 125 mg/kg (medium-dose group) and 175 mg/kg (high-dose group) on day 0. Sequential [(18)F]FDG small-animal PET (microPET) scans were performed on days 0, 2, 6, 9, 13 and 16 after treatment. The mean and maximum standardized uptake value (SUV(mean) and SUV(max)), metabolic tumour volume (Vol(metab)) and total lesion glycolysis (TLG) were calculated.

RESULTS

A significant decrease in [(18)F]FDG uptake was observed on day 2 in the medium-dose and high-dose groups and on day 6 in the low-dose group, all preceding morphological changes. SUV(mean) and SUV(max) formed a plateau from day 6 to day 9, corresponding to the known influx of inflammatory cells. No obvious plateau was observed with TLG which was found to be the most sensitive parameter clearly differentiating the low-dose group from the medium- and high-dose groups early after therapy.

CONCLUSION

[(18)F]FDG uptake was able to reflect the dose-response relationship for cyclophosphamide. TLG was the best parameter for dose-related response assessment in this tumour model.

Exhaled nitric oxide and nitric oxide synthase expression in Hodgkin's disease

Hodgkin's disease (HD) is a malignant lymphoma with frequent mediastinal involvement, characterized by a significant inflammatory infiltration. Exhaled nitric oxide (FENO), is present in healthy humans, and has been proven to be increased in eosinophilic diseases such as allergic asthma. We investigated whether FENO is increased in mediastinal HD and whether NO is produced by lymphoma tissue. To this aim FENO was measured in 56 HD patients, 17 with and 39 without bulky mediastinal involvement, in the period from January 2007 to December 2008. Thirty-seven patients were reassessed after remission. Lymph node biopsies of 10 patients were evaluated for inducible (iNOS) and constitutive (eNOS) nitric oxide synthase expression by immunohistochemistry. FENO resulted significantly related to the mediastinal mass maximum diameter (p=0.009) and was significantly higher in patients with as compared to those without bulky mediastinal disease (38.7 ppb, CI 95% 19.3-58.0, versus 20.7 ppb, CI 95% 16.6-24.7; p=0.009). iNOS and eNOS immunoreactivity was observed in tumour and inflammatory cells (eosinophils and histiocytes). Only in patients with bulky mediastinal HD there was a significant decrease in FENO (from 50.4 ppb CI 95% 18.0-82.8 to 11.1 ppb CI 95% 4.4-17.8, p=0.011). In conclusion, high FENO and NOS expression in lymph-nodes indicate that NO is a component of the inflammatory network of HD. FENO may be proposed for the assessment and follow up of bulky mediastinal HD patients.

PET imaging in lymphoma

PET has become a cornerstone procedure in modern lymphoma management. This paper reviews, from a clinical point of view, the evidence for using PET in the different subtypes of lymphoma and the different steps of their management. The reader is given an overview of the current PET-based interventional lymphoma trials and an insight into possible future developments in the field, including new PET tracers.

18F-FDG PET/CT for monitoring the response of lymphoma to radioimmunotherapy

We retrospectively evaluated 18F-FDG PET/CT for monitoring the response of non-Hodgkin's lymphoma to radioimmunotherapy.

METHODS

A total of 33 clinical patients received 131I-tositumomab (n=23) or 90Y-ibritumomab tiuxetan (n=10) and underwent 18F-FDG PET/CT scans before radioimmunotherapy and at 12 wk after radioimmunotherapy. A third scan was performed on 13 patients at 24 wk after radioimmunotherapy, 12 of whom did not receive interval therapy. Tumor metabolic activity was assessed before and after radioimmunotherapy visually and quantitatively by lean maximum standardized uptake value (SUVlean max). Response was assessed by the International Workshop Criteria (IWC) and Revised IWC, which includes 18F-FDG PET (IWC-PET).

RESULTS

Mean SUVlean max decreased from baseline in 244 target lesions 12 wk after radioimmunotherapy (from 6.51+/-4.05 to 3.94+/-4.41; P<0.01), regardless of response at 12 wk after radioimmunotherapy (P<or=0.02). After radioimmunotherapy, SUVlean max was lower for responders than for nonresponders (P<or=0.01). Median percentage change in SUVlean max of target lesions per patient was -51% (-95% to 97%). No significant difference in decline in SUVlean max between patients who received 131I-tositumomab and those who received 90Y-ibritumomab tiuxetan was demonstrated (-31%+/-51% vs. -47%+/-46%; P=0.38). Patients with greater than a 52% decline in SUVlean max tended toward longer survival (P=0.09) than those with lesser declines. The 12-wk overall response rate to radioimmunotherapy based on IWC was 42% (14/33); complete response rate was 15% (5/33). Eleven of 12 patients with progression at 12 wk had new disease sites, and in 4 patients, new disease sites were the only sites of progression. Of 108 lesions evaluated at 12 and 24 wk after radioimmunotherapy, 49 resolved at 12 wk and remained resolved at 24 wk, 17 gradually declined in SUV over 24 wk, and 37 initially decreased at 12 wk but increased at 24 wk. PET showed disease progression at 24 wk in 10 of 13 patients; 7 patients had new lesions and 1 was reclassified from partial response to complete response.

CONCLUSION

In non-Hodgkin's lymphoma, 18F-FDG uptake in tumors typically drops significantly after radioimmunotherapy. A continued decline in tumor SUVlean max between 12 and 24 wk without additional therapy can occur, suggesting a need for delayed-response assessment. In patients who progress after radioimmunotherapy, new sites of disease commonly develop, rather than recurrence or progression at previous disease sites. Large declines in 18F-FDG uptake tend to be seen in those with the longest progression-free survival.

Positron emission tomography in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare but aggressive non-Hodgkin lymphoma subtype with a poor prognosis; most patients relapse despite initial response to therapy. Response was traditionally evaluated by computed tomography (CT), but the introduction of [(18)F]Fluorine-Deoxyglucose Positron Emission Tomography (PET) changed response assessment in aggressive lymphoma. However, the value of PET-evaluation in MCL has not been studied yet. Therefore, PET- and CT-findings were investigated in 37 patients with MCL (239 scans) and categorised following standardised response criteria for CT-evaluation (IWC-criteria), PET-evaluation (EORTC-criteria) and combined PET/CT-evaluation (IWC + PET-criteria). FDG-PET showed a high sensitivity for the detection of deposits of MCL and a higher FDG-uptake was shown in patients with the more aggressive blastoid-variant of MCL versus common MCL. However, routine use of PET for end-of-treatment response assessment in MCL cannot be recommended because CT- and PET-based designation systems had equivalent prognostic value. PET-based end-of-treatment response assessment only provided additional information over CT-based response assessment in a subpopulation of patients with highly FDG-avid MCL. PET allowed early detection of preclinical relapse during post-therapy surveillance, but the therapeutic consequences of such information are currently unclear.

Allogeneic transplantation for Hodgkin lymphoma

The majority of patients with Hodgkin lymphoma (HL) can now expect to be cured with conventional chemo- and/or radio-therapy. However, a subgroup still exists that have poor outcomes, even following dose escalation and autologous stem cell transplantation. Furthermore, patients relapsing after autografting have limited therapeutic options available. Whilst the application of allogeneic transplantation strategies has historically been limited by prohibitive transplant-related mortality, the exploration of reduced intensity approaches has demonstrated the feasibility of delivering allogeneic immunotherapies with more acceptable mortality rates. Although its role remains controversial, we are beginning to re-evaluate the use of allogeneic transplantation in the management of patients with HL and to address a number of critical questions. These include whether a clinically relevant graft-versus-tumour response occurs in HL, and whether subgroups of patients who might benefit from allogeneic approaches can be identified in order to inform development of rational clinical studies. This review focuses on evaluating recent experience with reduced intensity allogeneic approaches in HL in order to inform opinion on its current role and to highlight areas for future investigation.

FDG-PET Evaluation of Response to Treatment

This article discusses evaluating response after and during therapy in various settings and for the types of cancers for which ample evidence demonstrates that PET imaging with flourodeoxyglucose provides a valuable surrogate for response to therapy. It also briefly discusses pitfalls in obtaining an optimal assessment of response and issues that need further attention for this modality to become established as an independent predictor of response to anticancer therapy.