Role of imaging in the staging and response assessment of lymphoma: consensus of the International Conference on Malignant Lymphomas Imaging Working Group

Imaging for Staging and Response Assessment in Lymphoma

Lymphoma comprises a heterogeneous group of diseases; remarkable advances have been made in diagnosis and treatment. Diagnostic imaging provides important information for staging and response assessment in patients with lymphoma. Over the years, staging systems have been refined, and dedicated criteria have been developed for evaluating response to therapy with both computed tomography (CT) and fluorine-18 fluorodeoxyglucose positron emission tomography (PET)/CT. The most recent system proposed for staging and response assessment, known as the Lugano classification, applies to both Hodgkin and non-Hodgkin lymphoma. The use of standardized criteria for staging and response assessment is important for making accurate treatment decisions and for determining the direction of further research. This review provides an overview of the updated CT and PET response criteria to familiarize the radiologist with the most important and clinically relevant aspects of lymphoma imaging. It also provides a short clinical update on lymphoma and the associated spectrum of imaging findings.

PET-directed therapy in Hodgkin lymphoma: Ready for prime time?

Advances in chemotherapy and radiation therapy have allowed the vast majority of patients with Hodgkin lymphoma to be cured, but some of these patients develop treatment-related complications, including second malignancies, cardiovascular disease, and thyroid disease. Efforts to decrease exposure of patients to more chemotherapy or radiation therapy than is necessary to cure their disease have led to a trend toward shortened treatment regimens in patients with low-risk disease. Predicting which patients will relapse, and therefore might benefit from a more intense treatment regimen, has been a clinical challenge. PET has emerged as a useful modality in the diagnosis and management of Hodgkin lymphoma, and has been studied as a potential tool to help the oncologist to utilize the optimal chemotherapy and radiation therapy regimen for each patient.

[The prognosis value of early and interim ¹⁸F-FDG-PET/CT scans in patients with diffuse large B-cell lymphoma]

OBJECTIVE

To investigate the prognosis value of early and interim ¹⁸F-FDG-PET/CT scan in patients with diffuse large B- cell lymphoma （DLBCL） to establish the suitable criteria for evaluating posttherapeutic lesions in scans.

METHODS

Fifty- six newly diagnosed DLBCL patients were enrolled in the study, and underwent baseline, early and interim ¹⁸F- FDG PET/CT scans. Five- point and % ΔSUVmax criteria were used separately to interpret ¹⁸F- FDG PET/CT images. Interobserver reproducibility was assessed with the kappa test（κ）, and thresholds of %ΔSUVmax were calculated via receiver operating characteristic curve（ROC）. Survival curves were obtained using Kaplan-Meier curves and log-rank test. Cox regression analysis was used for multi-factor analysis.

RESULTS

Median follow-up was 24 months（6 to 42 months）. The kappa value of the five- point scale was above 0.600 with the reference background set in the liver（Score≥4）. The optimal threshold of %ΔSUVmax was 81% for early PET/CT and 74% for interim PET/CT. Survival analysis showed both early and interim PET/CT scans could predict the outcome of 56 patients with DLBCL, and 3-year PFS and OS of PET-negative patients were significantly higher than those of PET-positive ones（P<0.05）. Five-score criteria were more accurate in evaluating 3- year PFS of DLBCL patients in the interim PET/CT scan（76.79%）. %ΔSUVmax criteria were better for interpreting 3-year OS（76.79% and 83.93%）. Multi-factor analysis demonstrated that early and interim PET/CT were solid predicting factors for DLBCL patients.

CONCLUSION

Early and interim PET/CT scans could predict the outcome of patients with DLBCL, treated with R-CHOP/CHOP. Three-year OS was more accurate in early and interim PET/CT using 66 %ΔSUVmax criteria as an interpretation, while 3-year PFS was more accurate in interim PET/CT by five scores criteria.

Lymph nodes can accurately be measured on PET-CT for lymphoma staging/restaging without a concomitant contrast enhanced CT scan

Dual imaging with both contrast enhanced CT scan and PET-CT is recommended for evaluation of lymphoma. We compared the performance in identification and size measurements of involved lymph nodes in FDG-avid lymphomas on the low dose non-contrast enhanced CT of a PET-CT scan with those on a diagnostic contrast enhanced CT scan. The size of FDG-avid lymph nodes was measured in both the short and long axis on both the low dose non-contrast CT of the PET-CT and the contrast enhanced CT by two independent readers. A total of 307 FGD avid lymph nodes were identified in 52 patients. There was no statistically significant differences in the measured size of the nodes on the non-contrast and contrast enhanced scans (p=0.21). Baseline staging and restaging of FDG-avid lymphomas can be performed with one test, PET-CT, without an accompanying contrast enhanced CT scan, with no effect on the measured nodal size.

The Prognostic Significance of Metabolic Response Heterogeneity in Metastatic Colorectal Cancer

Background

Tumoral heterogeneity is a major determinant of resistance in solid tumors. FDG-PET/CT can identify early during chemotherapy non-responsive lesions within the whole body tumor load. This prospective multicentric proof-of-concept study explores intra-individual metabolic response (mR) heterogeneity as a treatment efficacy biomarker in chemorefractory metastatic colorectal cancer (mCRC).

Methods

Standardized FDG-PET/CT was performed at baseline and after the first cycle of combined sorafenib (600mg/day for 21 days, then 800mg/day) and capecitabine (1700 mg/m²/day administered D1-14 every 21 days). MR assessment was categorized according to the proportion of metabolically non-responding (non-mR) lesions (stable FDG uptake with SUVmax decrease <15%) among all measurable lesions.

Results

Ninety-two patients were included. The median overall survival (OS) and progression-free survival (PFS) were 8.2 months (95% CI: 6.8–10.5) and 4.2 months (95% CI: 3.4–4.8) respectively. In the 79 assessable patients, early PET-CT showed no metabolically refractory lesion in 47%, a heterogeneous mR with at least one non-mR lesion in 32%, and a consistent non-mR or early disease progression in 21%. On exploratory analysis, patients without any non-mR lesion showed a significantly longer PFS (HR 0.34; 95% CI: 0.21–0.56, P-value <0.001) and OS (HR 0.58; 95% CI: 0.36–0.92, P-value 0.02) compared to the other patients. The proportion of non-mR lesions within the tumor load did not impact PFS/OS.

Conclusion

The presence of at least one metabolically refractory lesion is associated with a poorer outcome in advanced mCRC patients treated with combined sorafenib-capecitabine. Early detection of treatment-induced mR heterogeneity may represent an important predictive efficacy biomarker in mCRC.

Trial Registration

ClinicalTrials.gov NCT01290926

Concordance in the interpretation of PET after chemotherapy in advanced stage Hodgkin lymphoma

The aim was to analyze the degree of agreement between the central review panel and the local PET interpretation within the HD15 trial and its impact on subsequent treatment and progression free survival.

PATIENTS, METHODS

The analysis set consisted of 739 patients with residues ≥ 2.5 cm after 6 or 8 cycles of BEACOPPesc from the HD15 trial performed by the German Hodgkin Study Group. The recommendation for or against further radiotherapy was based on the central [(18)F]FDG-PET interpretation. Central PET interpretation was compared to the local PET interpretation and concordance was measured using Cohen's Kappa coefficient. Prognostic impact of the analysis of concordance between local and central PET interpretations was evaluated using progression free survival (PFS); groups were compared with the log rank test.

RESULTS

The central panel rated 548 of 739 patients (74%) as PET negative. Of these, 513 were also rated as PET negative in the local PET interpretation. PET positivity was seen by central reviewers in the remaining 191 patients (26%), in concordance with local reviewers in 155 cases. Even though substantial agreement was found (Cohen's Kappa 0.81), the interpretation of the central PET review panel led to a different therapeutic recommendation in 71/739 (10%) patients. PFS was equally high in groups in which the therapeutic regime had been changed on the basis of the central panel decision.

CONCLUSION

High concordance is found between local and central reviewers with regard to PET interpretation in residual tissue after intense chemotherapy. The existence of the central PET review panel allows the identification of additional patients as PET negative so that radiotherapy can be safely omitted (35 of 548 patients = 4.7%).

How I treat posttransplant lymphoproliferative disorders

Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal disorder arising after solid organ transplant (SOT) or hematopoietic stem cell transplant (HSCT). Iatrogenically impaired immune surveillance and Epstein-Barr virus (EBV) primary infection/reactivation are key factors in the pathogenesis. However, current knowledge on all aspects of PTLD is limited due to its rarity, morphologic heterogeneity, and the lack of prospective trials. Furthermore, the broad spectrum of underlying immune disorders and the type of graft represent important confounding factors. Despite these limitations, several reviews have been written aimed at offering a guide for pathologists and clinicians in diagnosing and treating PTLD. Rather than providing another classical review on PTLD, this "How I Treat" article, based on 2 case reports, focuses on specific challenges, different perspectives, and novel insights regarding the pathogenesis, diagnosis, and treatment of PTLD. These challenges include the wide variety of PTLD presentation (making treatment optimization difficult), the impact of EBV on pathogenesis and clinical behavior, and the controversial treatment of Burkitt lymphoma (BL)-PTLD.

Evaluation of the International Prognostic Score (IPS-7) and a Simpler Prognostic Score (IPS-3) for advanced Hodgkin lymphoma in the modern era

The International Prognostic Score (IPS-7) is the most commonly used risk stratification tool for advanced Hodgkin lymphoma (HL), however recent studies suggest the IPS-7 is less discriminating due to improved outcomes with contemporary therapy. We evaluated the seven variables for IPS-7 recorded at study entry for 854 patients enrolled on Eastern Cooperative Oncology Group 2496 trial. Univariate and multivariate Cox models were used to assess their prognostic ability for freedom from progression (FFP) and overall survival (OS). The IPS-7 remained prognostic however its prognostic range has narrowed. On multivariate analysis, two factors (age, stage) remained significant for FFP and three factors (age, stage, haemoglobin level) for OS. An alternative prognostic index, the IPS-3, was constructed using age, stage and haemoglobin level, which provided four distinct risk groups [FFP (P = 0·0001) and OS (P < 0·0001)]. IPS-3 outperformed the IPS-7 on risk prediction for both FFP and OS by model fit and discrimination criteria. Using reclassification calibration, 18% of IPS-7 low risk patients were re-classified as intermediate risk and 13% of IPS-7 intermediate risk patients as low risk. For patients with advanced HL, the IPS-3 may provide a simpler and more accurate framework for risk assessment in the modern era. Validation of these findings in other large data sets is planned.

Impact of PET/CT image reconstruction methods and liver uptake normalization strategies on quantitative image analysis

BACKGROUND

In oncological imaging using PET/CT, the standardized uptake value has become the most common parameter used to measure tracer accumulation. The aim of this analysis was to evaluate ultra high definition (UHD) and ordered subset expectation maximization (OSEM) PET/CT reconstructions for their potential impact on quantification.

PATIENTS AND METHODS

We analyzed 40 PET/CT scans of lung cancer patients who had undergone PET/CT. Standardized uptake values corrected for body weight (SUV) and lean body mass (SUL) were determined in the single hottest lesion in the lung and normalized to the liver for UHD and OSEM reconstruction. Quantitative uptake values and their normalized ratios for the two reconstruction settings were compared using the Wilcoxon test. The distribution of quantitative uptake values and their ratios in relation to the reconstruction method used were demonstrated in the form of frequency distribution curves, box-plots and scatter plots. The agreement between OSEM and UHD reconstructions was assessed through Bland-Altman analysis.

RESULTS

A significant difference was observed after OSEM and UHD reconstruction for SUV and SUL data tested (p < 0.0005 in all cases). The mean values of the ratios after OSEM and UHD reconstruction showed equally significant differences (p < 0.0005 in all cases). Bland-Altman analysis showed that the SUV and SUL and their normalized values were, on average, up to 60 % higher after UHD reconstruction as compared to OSEM reconstruction.

CONCLUSION

OSEM and HD reconstruction brought a significant difference for SUV and SUL, which remained constantly high after normalization to the liver, indicating that standardization of reconstruction and the use of comparable SUV measurements are crucial when using PET/CT.

The importance of radiotherapy on diffuse large B cell lymphoma treatment: a current review

Diffuse large B cell lymphoma is recognized as a heterogeneous group of hematological malignancies; two main subtypes germinal center B and activated B cells are well defined although 15% of patients remain with unclassifiable disease. R-CHOP treatment has proven to provide very effective results in limited or advanced stage of the disease. However, treatment solely involving R-CHOP submits the patient to possible chemotherapy-induced toxicities, which may be avoided with the use of radiotherapy. Patients with early stage localized disease or who are particularly unresponsive to chemotherapy may be more suitable for mixed modality treatment with R-CHOP and consolidative radiotherapy. Although radiotherapy is being slowly phased out by other treatment strategies including chemotherapy and therapeutic drugs, it is still a highly important method of treatment. The different forms of radiotherapy can be used alongside these "new-age" treatment strategies to further improve prognostic outcomes and overall survival rates. The establishment of radiotherapy as a treatment strategy provides a highly beneficial prognostic advantage in early stage, localized disease.

Prognostic Value of Anemia and C-Reactive Protein Levels in Diffuse Large B-Cell Lymphoma

PURPOSE

To determine the prognostic value of pretreatment anemia, pretreatment elevated C-reactive protein (CRP) levels, and 6-month posttreatment anemia in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) treated with rituximab, cyclophosphamide, hydroxydaunorubicin, Oncovin, and prednisolone (R-CHOP).

PATIENTS AND METHODS

A total of 104 patients with newly diagnosed DLBCL were retrospectively included. Pretreatment hemoglobin and CRP levels and 6-month posttreatment hemoglobin levels were measured. Cox regression analyses were used to determine the associations of laboratory assessments and National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) risk groups with progression-free survival (PFS) and overall survival (OS).

RESULTS

Pretreatment anemia, elevated pretreatment CRP levels, and higher risk NCCN-IPI groups were significantly associated with reduced PFS and OS (P = .001 and P = .003 for pretreatment anemia, P = .035 and P = .029 for elevated CRP, and P < .001 and P < .001 for higher risk NCCN-IPI groups). On multivariate Cox regression analysis, only the NCCN-IPI risk group remained as an independent significant predictor for PFS (P < .001) and OS (P < .001). In the subgroup of patients in complete remission 6 months after chemotherapy (n = 80), 6-month posttreatment anemia was significantly associated with reduced PFS (P = .046) but not OS (P = .062), and higher risk NCCN-IPI groups were significantly associated with both reduced PFS (P = .008) and OS (P = .017). On multivariate Cox regression analysis, only the NCCN-IPI group remained an independent significant predictor for PFS (P = .008) and OS (P = .017).

CONCLUSION

Pretreatment anemia, pretreatment CRP levels, and 6-month posttreatment anemia are significantly associated with poor outcome, but were not proven to be of additional prognostic value to the current risk stratification index for DLBCL.

The role of bone marrow biopsy and FDG-PET/CT in identifying bone marrow infiltration in the initial diagnosis of high grade non-Hodgkin B-cell lymphoma and Hodgkin lymphoma. Accuracy in a multicenter series of 372 patients

Bone marrow infiltration (BMI), categorized as an extra-nodal site, affects stage and is associated with poor prognosis in newly diagnosed lymphoma patients. We have evaluated the accuracy of PET/CT and bone marrow biopsy (BMB) to assess BMI in 372 lymphoma patients [140 Hodgkin Lymphoma (HL) and 232 High Grade B-cell non-Hodgkin Lymphoma (HG B-NHL), among them 155 Diffuse Large B-Cell Lymphoma (DLCL)]. For HL cases, and taking into account PET/CT, sensitivity, negative predictive value (NPV) and accuracy were 96.7, 99.3, and 99.3% while those of BMB were 32.3, 83.8, and 85%, respectively. For HG B-NHL and considering PET/CT, sensitivity, NPV, and accuracy were 52.7, 81.7, and 84.1%, while those of BMB were 77.6, 90.2, and 90.7%, respectively. In the HG B-NHL group, 25 patients would have been under-staged without BMB. These results lead us to recommend PET/CT and the avoidance of BMB to assess BMI in HL. In the case of HG B-NHL, bone marrow status should be assessed firstly by means of PET/CT; only in either focal or diffuse PET/CT with low borderline SUV max values or in negative cases, should BMB be carried out afterwards. In the HG B-NHL setting and at the present moment, both techniques are complementary.

Non-Hodgkin Lymphoma: Diagnosis and Treatment

Non-Hodgkin lymphomas are lymphoid malignant neoplasms with diverse biological and clinical behavior. Patients typically present with persistent painless lymphadenopathy, but some patients may present with constitutional symptoms or with involvement of organs other than the lymphoid and hematopoietic system. An accurate diagnosis, careful staging of the disease, and identification of adverse prognostic factors form the basis of treatment selection. Patients commonly receive chemoimmunotherapy as initial treatment, and radiation therapy may be added if patients have early-stage disease. Most patients respond well to treatment, but relapses are frequent and additional therapies including stem cell transplant are often needed. Because many subtypes of lymphoma remain incurable with current management strategies, clinical trials are in progress to identify novel therapies with promising activity in this disease.

Harmonizing FDG PET quantification while maintaining optimal lesion detection: prospective multicentre validation in 517 oncology patients

PURPOSE

Point-spread function (PSF) or PSF + time-of-flight (TOF) reconstruction may improve lesion detection in oncologic PET, but can alter quantitation resulting in variable standardized uptake values (SUVs) between different PET systems. This study aims to validate a proprietary software tool (EQ.PET) to harmonize SUVs across different PET systems independent of the reconstruction algorithm used.

METHODS

NEMA NU2 phantom data were used to calculate the appropriate filter for each PSF or PSF+TOF reconstruction from three different PET systems, in order to obtain EANM compliant recovery coefficients. PET data from 517 oncology patients were reconstructed with a PSF or PSF+TOF reconstruction for optimal tumour detection and an ordered subset expectation maximization (OSEM3D) reconstruction known to fulfil EANM guidelines. Post-reconstruction, the proprietary filter was applied to the PSF or PSF+TOF data (PSFEQ or PSF+TOFEQ). SUVs for PSF or PSF+TOF and PSFEQ or PSF+TOFEQ were compared to SUVs for the OSEM3D reconstruction. The impact of potential confounders on the EQ.PET methodology including lesion and patient characteristics was studied, as was the adherence to imaging guidelines.

RESULTS

For the 1380 tumour lesions studied, Bland-Altman analysis showed a mean ratio between PSF or PSF+TOF and OSEM3D of 1.46 (95%CI: 0.86-2.06) and 1.23 (95%CI: 0.95-1.51) for SUVmax and SUVpeak, respectively. Application of the proprietary filter improved these ratios to 1.02 (95%CI: 0.88-1.16) and 1.04 (95%CI: 0.92-1.17) for SUVmax and SUVpeak, respectively. The influence of the different confounding factors studied (lesion size, location, radial offset and patient's BMI) was less than 5%. Adherence to the European Association of Nuclear Medicine (EANM) guidelines for tumour imaging was good.

CONCLUSION

These data indicate that it is not necessary to sacrifice the superior lesion detection and image quality achieved by newer reconstruction techniques in the quest for harmonizing quantitative comparability between PET systems.

A case of Hodgkin lymphoma in a patient with a history of bone pain and an initial diagnosis of chronic osteomyelitis

Hodgkin lymphoma (HL) is an uncommon monoclonal lymphoid malignancy consisting of 2 main entities: classical HL and nodular lymphocyte predominant. Hodgkin lymphoma usually presents with peripheral lymphadenopathies, while extranodal involvement is rare. Prevalent osseous presentation is rare and still misdiagnosed, despite improvements in diagnostic techniques. Here we report the case of a 30-year-old man with multifocal HL bone involvement initially misdiagnosed as chronic recurrent osteomyelitis. This case emphasizes the difficulties in the diagnosis of HL presenting with bone pain and with radiologic skeletal findings not specific for lymphoma. These patients often have diagnostic delays and misdiagnosis. Repeated investigations and clinical suspicion of unusual presentations may be helpful in order to establish a correct diagnosis and start an effective treatment in this highly curable disease.

Opportunities and limitations of bone marrow biopsy and bone marrow FDG-PET in lymphoma

Bone marrow involvement in lymphoma may have prognostic and therapeutic consequences. Bone marrow biopsy (BMB) is the established method for the evaluation of the bone marrow. (18)F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) plays an important role in lymphoma staging, but its value in the assessment of the bone marrow and whether it can replace BMB is still a topic of debate and investigation. The purpose of this scientific communication is to provide an evidence-based overview about the opportunities and limitations of BMB and FDG-PET in the evaluation of the bone marrow in patients with lymphoma. This article first reviews the basic properties, opportunities and limitations of BMB and bone marrow FDG-PET, and then focuses on the clinical utility of BMB and bone marrow FDG-PET in three major lymphoma subtypes including Hodgkin lymphoma, diffuse large B-cell lymphoma, and follicular lymphoma.

Prognostic Value of FDG PET/CT before Allogeneic and Autologous Stem Cell Transplantation for Aggressive Lymphoma

PURPOSE

To determine the prognostic value of performing fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) before allogeneic and autologous stem cell transplantation (SCT) in patients with aggressive lymphoma.

MATERIALS AND METHODS

A HIPAA-compliant retrospective review was performed under institutional review board waiver. Patients with aggressive lymphoma underwent allogeneic or autologous SCT between January 2005 and December 2010. FDG PET/CT was performed within the 3 months prior to transplantation. PET/CT images were evaluated for lesions with FDG avidity greater than that of the background liver. The relationship between pretransplantation PET and progression-free survival (PFS), disease-specific survival (DSS), and overall survival (OS) was assessed with Kaplan-Meier curves and a corresponding log-rank test for categorical variables and Cox regression for continuous variables.

RESULTS

A total of 175 patients were identified, of whom 73 underwent FDG PET/CT before allogeneic SCT and 102 underwent FDG PET/CT before autologous SCT. Before allogeneic SCT, 23 of 73 patients (32%) had FDG-avid lesions, and before autologous SCT, 11 of 102 patients (11%) had FDG-avid lesions. For allogeneic SCT, the 2-year PFS estimate was 68% (95% confidence interval [CI]: 56%, 82%) in patients without FDG-avid lesions, but only 35% (95% CI: 20%, 61%) for patients with FDG-avid lesions (P = .014). For autologous SCT, the 2-year PFS was 72% (95% CI: 64%, 82%) in patients without FDG-avid lesions, but only 18% (95% CI: 5%, 64%) for patients with FDG-avid lesions (P < .0001). Similar differences were seen in OS and DSS. The risk for posttransplantation recurrence correlated with higher lesional maximum standardized uptake values: for PFS, P < .0001 to P = .01; for DSS, P < .0001 to P = .002; and for OS, P < .0001 to P = .015.

CONCLUSION

Performing FDG PET/CT before SCT in patients with aggressive lymphoma has prognostic value. For patients with aggressive lymphomas, the presence of FDG-avid lesions at PET/CT performed before allogeneic and autologous SCT indicates a lower likelihood of SCT success.

Phase II study of interim PET-CT-guided response-adapted therapy in advanced Hodgkin's lymphoma

BACKGROUND

Combination chemotherapy ABVD (doxorubicin, bleomycin, vinblastine and dacarabazine) cures ∼70% of patients with advanced Hodgkin's lymphoma (aHL, stages IIB, III and IV) while more toxic escalated BEACOPP (EB, combination of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisolone) increases cure rates to 85%. Patients with a positive interim positron emission tomography-computerized tomography (PET-CT) scan after two cycles (PET-2) of ABVD have very poor outcomes with continued ABVD. Intensifying therapy with EB in PET-2-positive patients ('response-adapted therapy') may improve cure rates, whereas the negative patients can continue ABVD alone.

PATIENTS AND METHODS

Eligible patients with newly diagnosed aHL received two cycles of ABVD and underwent PET-2 (scored with semi-quantitative 5-point visual criteria, 'Deauville score'). PET-2-negative patients continued four additional cycles of ABVD, whereas PET-2-positive patients received four cycles of EB. A phase II sample size of 50 was estimated keeping the lower and higher proportion of rejection of the event-free survival (EFS) as 70% and 85%, respectively.

RESULTS

Fifty patients [median age 28 (12-60) years; male : female: 39 : 11; stages: IIB-3 (6%), III-29 (58%) and IV-18 (36%); International Prognostic Score (IPS): 0-3: 34 (68%); 4-7: 16 (32%)] were enrolled; 49 underwent PET-2. Eight (16%) were PET-2-positive, whereas 41 (84%) were negative. Forty-seven were evaluable for EFS and all 50 for overall survival (OS). The 2-year EFS was 76% (95% CI: 68-83) and OS was 88% (95% CI: 82-94). PET-2 was strongly prognostic-2-year EFS, negative versus positive: 82% versus 50%; P = 0.013.

CONCLUSION

PET-2 response-adapted strategy could not achieve EFS of 85% in aHL. However, escalated therapy improved outcomes in PET-2-positive patients compared with historical data.

TRIAL REGISTRATION

CTRI/2012/06/002741 (http://www.ctri.nic.in) and NCT01304849 (http://www.clinicaltrials.gov).

Impact of Pretransplantation (18)F-fluorodeoxy Glucose-Positron Emission Tomography Status on Outcomes after Allogeneic Hematopoietic Cell Transplantation for Non-Hodgkin Lymphoma

Assessment with (18)F-fluorodeoxy glucose (FDG)-positron emission tomography (PET) before hematopoietic cell transplantation (HCT) for lymphoma may be prognostic for outcomes. Patients with chemotherapy-sensitive non-Hodgkin lymphoma (NHL) undergoing allogeneic HCT reported to the Center of International Blood and Marrow Transplantation Registry between 2007 and 2012 were included. Pre-HCT PET status (positive versus negative) was determined by the reporting transplantation centers. We analyzed 336 patients; median age was 55 years and 60% were males. Follicular lymphoma (n = 104) was more common than large cell (n = 85), mantle cell (n = 69), and mature natural killer or T cell lymphoma (n = 78); two thirds of the cohort received reduced-intensity conditioning; one half had unrelated donor grafts. Patients underwent PET scanning a median of 1 month (range, .07 to 2.83 months) before HCT; 159 were PET positive and 177 were PET negative. At 3 years, relapse/progression, progression-free survival (PFS), and overall survival (OS) in PET-positive versus PET-negative groups were 40% versus 26%; P = .007; 43% versus 47%; P = .47; and 58% versus 60%; P = .73, respectively. On multivariate analysis, a positive pretransplantation PET was associated with an increased risk of relapse/progression (risk ratio [RR], 1.86; P = .001) but was not associated with increased mortality (RR, 1.29, 95% confidence interval [CI], .96 to 1.7; P = .08), therapy failure (RR, 1.32; 95% CI, .95 to 1.84; P = .10), or nonrelapse mortality (RR, .75; 95% CI, .48 to 1.18; P = .22). PET status conferred no influence on graft-versus-host disease. A positive PET scan before HCT is associated with increased relapse risk but should not be interpreted as a barrier to a successful allograft. PET status does not appear to predict survival after allogeneic HCT for NHL.

International Pediatric Non-Hodgkin Lymphoma Response Criteria

PURPOSE

Response criteria are well established for adult patients with non-Hodgkin lymphoma (NHL). A revised set of response criteria in adults with NHL was recently published. However, NHL in children and adolescents involves different histologies, primary sites of disease, patterns of metastatic spread, approaches to therapy, and responses to treatment compared with adult NHL. However, there are no standardized response criteria specific to pediatric NHL. Therefore, we developed international standardized methods for assessing response to therapy in children and adolescents with NHL.

METHODS

An international multidisciplinary group of pediatric oncologists, pathologists, biologists, and radiologists convened during and after the Third and Fourth International Childhood, Adolescent and Young Adult NHL Symposia to review existing response and outcome data, develop methods for response evaluation that reflect incorporation of more sensitive technologies currently in use, and incorporate primary and metastatic sites of disease for the evaluation of therapeutic response in children and adolescents with NHL.

RESULTS

Using the current adult NHL response criteria as a starting point, international pediatric NHL response criteria were developed incorporating both contemporary diagnostic imaging and pathology techniques, including novel molecular and flow cytometric technologies used for the determination of minimal residual disease.

CONCLUSION

Use of the international pediatric NHL response criteria in children and adolescents receiving therapy for NHL incorporates data obtained from new and more sensitive technologies that are now being widely used for disease evaluation, providing a standardized means for reporting treatment response.

Revised International Pediatric Non-Hodgkin Lymphoma Staging System

PURPOSE

Treatment and prognosis of pediatric non-Hodgkin lymphoma (NHL) have improved dramatically in the last 30 years. However, the St Jude NHL staging classification for pediatric NHL was developed more than 35 years ago. The most recent Lugano lymphoma staging classification focused on adult lymphoma. Furthermore, major limitations of the current pediatric NHL staging classification include lack of consideration of new distinct pediatric NHL histologic entities; absence of recognition of frequent skin, bone, kidney, ovarian, and other organ involvement; and lack of newer precise methods to detect bone marrow and CNS involvement, minimal disease quantification, and highly sensitive imaging technologies.

METHODS

An international multidisciplinary expert panel convened in Frankfurt, Germany, in 2009 at the Third International Childhood, Adolescent and Young Adult NHL Symposium to develop a revised international pediatric NHL staging system (IPNHLSS), addressing limitations of the current pediatric NHL staging system and creating a revised classification. Evidence-based disease distribution and behavior were reviewed from multiple pediatric cooperative group NHL studies.

RESULTS

A revised IPNHLSS was developed incorporating new histologic entities, extranodal dissemination, improved diagnostic methods, and advanced imaging technology.

CONCLUSION

This revised IPNHLSS will facilitate more precise staging for children and adolescents with NHL and facilitate comparisons of efficacy across different treatment strategies, various institutions, multicenter trials, and cooperative groups by allowing for reproducible pediatric-based staging at diagnosis and relapse.

Hodgkin lymphoma, version 2.2015

Hodgkin lymphoma (HL) is an uncommon malignancy involving lymph nodes and the lymphatic system. Classical Hodgkin lymphoma (CHL) and nodular lymphocyte-predominant Hodgkin lymphoma are the 2 main types of HL. CHL accounts for most HL diagnosed in the Western countries. Chemotherapy or combined modality therapy, followed by restaging with PET/CT to assess treatment response using the Deauville criteria (5-point scale), is the standard initial treatment for patients with newly diagnosed CHL. Brentuximab vedotin, a CD30-directed antibody-drug conjugate, has produced encouraging results in the treatment of relapsed or refractory disease. The potential long-term effects of treatment remain an important consideration, and long-term follow-up is essential after completion of treatment.

Imaging of non-Hodgkin lymphomas: diagnosis and response-adapted strategies

Optimal lymphoma management requires accurate pretreatment staging and reliable assessment of response, both during and after therapy. Positron emission tomography with computerized tomography (PET/CT) combines functional and anatomical imaging and provides the most sensitive and accurate methods for lymphoma imaging. New guidelines for lymphoma imaging and recently revised criteria for lymphoma staging and response assessment recommend PET/CT staging, treatment monitoring, and response evaluation in all FDG-avid lymphomas, while CT remains the method of choice for non-FDG-avid histologies. Since interim PET imaging has high prognostic value in lymphoma, a number of trials investigate PET-based, response-adapted therapy for non-Hodgkin lymphomas (NHL). PET response is the main determinant of response according to the new response criteria, but PET/CT has little or no role in routine surveillance imaging, the value which is itself questionable. This review presents from a clinical point of view the evidence for the use of imaging and primarily PET/CT in NHL before, during, and after therapy. The reader is given an overview of the current PET-based interventional NHL trials and an insight into possible future developments in the field, including new PET tracers.

Primary mediastinal large B-cell lymphoma

The management of primary mediastinal large B-cell lymphoma (PMBCL) requires a balance between optimizing chances of cure and reducing risk of long-term toxicities. The combination of rituximab to cyclophosphamide, doxorubicin, vincristine and prednisone (RCHOP) followed by mediastinal radiation results in a plateau in progression-free survival after first few years of follow-up. In rituximab era, a negative positron emission tomography (PET) scan performed after the completion of immunochemotherapy has a high predictive value for durable remission. Consequently, end-of-therapy PET may be utilizable to avoid radiation without compromising survival. Additionally, intensified chemotherapy alone has shown excellent survival. PMBCL is frequently associated with amplification of programmed death ligand (PDL) 1/2 and constitutive activation of JAK-STAT and NFKB pathways; these may serve as promising therapeutic targets. Clinical trials that integrate novel therapies into upfront immunochemotherapy and utilize end-of-therapy PET scan to guide mediastinal radiation have potential to further enhance survival and prevent long-term toxicities.

Brentuximab vedotin for treatment of relapsed or refractory malignant lymphoma: results of a systematic review and meta-analysis of prospective studies

Background

Recently, brentuximab vedotin has become a promising therapeutic approach for CD30-positive hematological malignancies, but its role in other relapsed or refractory malignant lymphoma needs to be proven. Brentuximab vedotin was demonstrated effective, but no study has summarized the concrete effect of brentuximab vedotin in malignant lymphoma. To truly know the role of brentuximab vedotin, we performed a systematic review of the literature and a meta-analysis of all known prospective trials, to assess the value of brentuximab vedotin for patients with relapsed and refractory malignant lymphoma.

Methods and materials

This was a systematic review of publications indexed in the PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and ISI Web of Knowledge performed on February 10, 2015. Six studies, including 302 patients were identified. Meta-analyses were carried out to calculate the objective response rate (ORR), complete response rate (CRR), and partial response rate (PRR) of brentuximab vedotin for malignant lymphoma.

Results

In patients with malignant lymphoma, ORR was 0.61, CRR was 0.38, and PRR was 0.51. High heterogeneity between studies was observed, and funnel plots were not symmetrical, which means that publication bias existed. Brentuximab vedotin was generally well-tolerated by patients reported in the included studies; adverse effects also occurred, but they were considered manageable.

Conclusion

Our analysis revealed a promising benefit of brentuximab vedotin in the treatment of relapsed and refractory malignant lymphoma. Larger sample of randomized controlled clinical trials are needed in the future.