Positron emission tomography/computed tomography surveillance in patients with Hodgkin lymphoma in first remission has a low positive predictive value and high costs

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

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

How I Follow Hodgkin Lymphoma in First Complete (Metabolic) Remission?

Hodgkin lymphoma is characterized by a high cure rate in the modern era of medicine regardless of stage, but patients suffer from a high risk of comorbidity associated with the administered therapy. The main aim of this review article is to assess and analyze the various comorbidities associated with Hodgkin lymphoma and address the survivorship of patients, including fertility, secondary cancers due to cardiovascular toxicity, and quality of life. Furthermore, this review explores the optimal strategy for detecting relapse. The treatment paradigm of Hodgkin lymphoma has shifted, with a paradigm shift toward achieving a high cure rate and low toxicity as a standard of care in this patient population. Checkpoint inhibitors, especially nivolumab, in combination with chemotherapy are increasingly being studied in the first line of therapy. However, their long-term toxicity remains to be assessed in longer follow-up. In conclusion, Hodgkin lymphoma survivors, regardless of their treatment, should be followed up individually by a multidisciplinary survivorship team in order to detect and properly treat the long-term side effects of therapy.

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

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

A systematic literature review of the epidemiology, quality of life, and economic burden, including disease pathways and treatment patterns of relapsed/refractory classical Hodgkin lymphoma

INTRODUCTION

A systematic literature review was conducted to understand disease burden in patients with relapsed/refractory classical Hodgkin lymphoma (R/R cHL).

AREAS COVERED

Embase®, PubMed®, and Cochrane were searched for records from 2001 to 2020 in accordance with PRISMA guidelines. A total of 13,257 abstracts and 1731 papers were screened; 144 studies were identified. cHL accounted for 0.5% of all cancers, with 4‒66.7% of cases progressing to R/R disease (studies with >500 patients); this range varied across countries. Quality of life (QoL) was assessed via EORTC-QLQ-C30 (n = 7), EQ-5D (n = 5), SF-36 (n = 3), FACIT-F (n = 1), and MFI (n = 1) questionnaires. In general, pembrolizumab and other programmed cell death protein-1 inhibitors improved QoL scores. Brentuximab vedotin showed mixed outcomes, and high-dose therapy (HDT) and autologous stem-cell rescue (ASCR) showed worsening functionality/symptoms. Economic burden studies (n = 21) reported increased costs and health care resource in R/R cHL. Across clinical guidelines (n = 13) and treatment pattern studies (n = 46), HDT followed by ASCR was recommended as initial R/R cHL treatment. Pembrolizumab and nivolumab were frequently recommended for patients relapsing following HDT/ASCR.

EXPERT OPINION

Despite recent treatment advances, patients with R/R cHL continue to report reduced quality of life. Unmet medical needs remain, particularly with respect to slowing disease progression and identifying the best treatment approaches for improving longer-term survival and quality of life. This systematic literature review provides an extensive overview of the current landscape in patients with R/R cHL, focusing on four key areas: epidemiology, QoL, economic burden, and disease management. These findings will be useful to those with an interest in managing patients with R/R cHL or in designing future studies.

Positron Emission Tomography Molecular Imaging for Phenotyping and Management of Lymphoma

Positron emission tomography (PET) represents molecular imaging for non-invasive phenotyping of physiological and biochemical processes in various oncological diseases. PET imaging with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) for glucose metabolism evaluation is the standard imaging modality for the clinical management of lymphoma. One of the ¹⁸F-FDG PET applications is the detection and pre-treatment staging of lymphoma, which is highly sensitive. ¹⁸F-FDG PET is also applied during treatment to evaluate the individual chemo-sensitivity and accordingly guide the response-adapted therapy. At the end of the therapy regiment, a negative PET scan is indicative of a good prognosis in patients with advanced Hodgkin's lymphoma and diffuse large B-cell lymphoma. Thus, adjuvant radiotherapy may be alleviated. Future PET studies using non-¹⁸F-FDG radiotracers, such as ⁶⁸Ga-labeled pentixafor (a cyclic pentapeptide that enables sensitive and high-contrast imaging of C-X-C motif chemokine receptor 4), ⁶⁸Ga-labeled fibroblast activation protein inhibitor (FAPI) that reflects the tumor microenvironment, and ⁸⁹Zr-labeled atezolizumab that targets the programmed cell death-ligand 1 (PD-L1), may complement ¹⁸F-FDG and offer essential tools to decode lymphoma phenotypes further and identify the mechanisms of lymphoma therapy.

Comparative analysis of international prognostic indices in gray-zone lymphoma

Gray-zone lymphoma (GZL) reflects an aggressive B-cell neoplasm with features intermediate between diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma (cHL). The International Prognostic Index (IPI) and its derivatives (R-IPI, NCCN-IPI, and the Hasenclever IPS) have been established for DLBCL or cHL while the most suitable scoring system for GZL remains undetermined. In an exploratory multi-centric cohort of GZL (n = 61), we performed a comparative analysis of prognostic indices with regard to model fit and mutual concordance. The calculation of the corrected Akaike's information criterion (cAIC) and Harrel's concordance index (c-index) for each scoring system identified the NCCN-IPI to harbor the most convincing prognostic capabilities regarding both overall survival (OS) and progression-free survival (PFS) compared to its enhanced derivatives. The current results affirm the clinical utility of the NCCN-IPI and suggest its preferential use in clinical practice in GZL-patients.

Limited benefit of additional contrast-enhanced CT to end-of-treatment PET/CT evaluation in patients with follicular lymphoma

Despite follicular lymphoma (FL) is frequently characterized by a moderate increase of glucose metabolism, PET/CT examinations provides valuable information for staging and response assessment of the disease. The aim of the study was to assess and compare the diagnostic performance of PET/ldCT and PET/ceCT, respectively, in evaluating FL patients at the end of treatment. Fifty FL consecutive patients who underwent end-of-therapy PET/CT with both ldCT and ceCT were analyzed. Two blinded observers independently assessed PET/ldCT and PET/ceCT applying the Deauville score (DS) and Lugano classification criteria. PET imaging obtained after the end-of-treatment (EoT) was classified as showing PET and ce-CT matched response (concordant imaging group, CIG) or PET and ce-CT unmatched response (discordant imaging group, DIG). Relapse rate and Event-Free Survival (EFS) were compared between CIG and DIG patients. Overall, no differences in metabolic response classification were observed between PET/ldCT and PET/ceCT. In 13 (26%) patients PET/ceCT identified additional FDG-negative nodal lesions in mesenteric, retroperitoneal and iliac regions. However, in all cases, final DS remained unchanged and the additional results did not modify the following therapeutic decision. Among patients, who obtained complete metabolic response a comparable rate of relapse was registered in DIG 3/13 (23%) and CIG subgroups 5/20 (25%) [p = 0.899]. In all 3 DIG cohort patients who relapsed the recurrent disease involved also, but not exclusively, PET negative lymph nodes detected by ceCT. In overall population metabolic response defined by PET/ldCT predicted EFS [76% (group of patients with metabolic response) vs 35% (group of patients with residual disease), p = 0.0013] significantly better than ceCT-Based response assessment [75% (group of patients with complete response) vs 53% (group of patients with residual disease), p = 0.06]. Our study demonstrates a negligible diagnostic and predictive value of ceCT performed in addition to standard ¹⁸FDG PET/ldCT for EoT response evaluation in FLs. PET/ldCT should be performed as first-line imaging procedure, also in patients with prevalent abdominal and pelvic involvement, limiting the acquisition of ceCT in selected cases. This tailored approach would contribute to avoid useless radiation exposure and preserve renal function of patients.

SEGHI Study: Defining the Best Surveillance Strategy in Hodgkin Lymphoma after First-Line Treatment

Simple Summary

As the optimal strategy for early surveillance after first complete response is unclear in Hodgkin lymphoma (HL), with the aim to identify the best one, we analyzed surveillance strategies after first-line treatment in a group of 640 Hodgkin lymphoma patients from 15 different GELTAMO centers in Spain. In this study, we have demonstrated that surveillance approaches with imaging in HL do not provide benefits for patient survival, nor do they anticipate relapse. Our results are of great importance, because they could contribute to improve the follow up after first complete response of this group of patients.

Abstract

The optimal strategy for early surveillance after first complete response is unclear in Hodgkin lymphoma. Thus, we compared the various follow-up strategies in a multicenter study. All the included patients had a negative positron emission tomography/computed tomography at the end of induction therapy. From January 2007 to January 2018, we recruited 640 patients from 15 centers in Spain. Comparing the groups in which serial imaging were performed, the clinical/analytical follow-up group was exposed to significantly fewer imaging tests and less radiation. With a median follow-up of 127 months, progression-free survival at 60 months of the entire series was 88% and the overall survival was 97%. No significant differences in survival or progression-free survival were found among the various surveillance strategies. This study suggests that follow-up approaches with imaging in Hodgkin lymphoma provide no benefits for patient survival, and we believe that clinical/analytical surveillance for this group of patients could be the best course of action.

Hodgkin Lymphoma, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology for Hodgkin Lymphoma (HL) provide recommendations for the management of adult patients with HL. The NCCN panel meets at least annually to review comments from reviewers within their institutions, examine relevant data, and reevaluate and update their recommendations. Current management of classic HL involves initial treatment with chemotherapy alone or combined modality therapy followed by restaging with PET/CT to assess treatment response. Overall, the introduction of less toxic and more effective regimens has significantly advanced HL cure rates. This portion of the NCCN Guidelines focuses on the management of classic HL.

Limiting surveillance imaging for patients with lymphoma in remission: a mixed methods study leading to a Choosing Wisely recommendation

BACKGROUND

Under the 'Choosing Wisely' (CW) framework, professional organisations internationally have advocated limiting imaging for asymptomatic patients following curative cancer therapy, based on limited value and high cost. F18-fluorodeoxyglucose (FDG) positron emission tomography-CT (PET/CT) was widely adopted locally for surveillance lymphoma imaging after 2004.

OBJECTIVES

Prior to ratification of a local CW recommendation to limit surveillance imaging in lymphoma, we aimed to assess: (A) performance characteristics of surveillance FDG-PET/CT; (B) rates, clinical consequences and costs of false positives (FP); and (C) patients and professionals' attitudes towards overuse.

METHODS

Mixed methods (quantitative and qualitative) study. We analysed surveillance FDG-PET/CT results of two patient cohorts (n1=215 Hodgkin lymphoma and non-Hodgkin lymphoma; n2=203 Hodgkin lymphoma only). FPs were defined by negative biopsy or clinical follow-up. We held focus group discussions and in-depth interviews eliciting attitudes of 26 patients and 11 clinicians, respectively.

RESULTS

FPs were observed in 25.1% (95% CI 20.5 to 30.5) per scan-cohort 1, and 41.7% (95% CI 37.9 to 45.6) per patient-cohort 2, engendering frequent additional testing. Specific characteristics and location of findings altered the FP rate. The estimated cost per relapse detected was $50 000 (cohort 2). Patients sought reassurance via surveillance imaging, which they considered highly accurate, yet stressful. Aware of radiation risks, they were largely unconcerned about consequences of FPs. Confidence in the treating physicians was an important factor in patients' acceptance of forgoing imaging. Clinicians, frequently under patient pressure to order imaging, generally believed that it did not affect prognosis (with important exceptions), welcomed professional guidelines, but rejected regulatory restrictions on its use.

CONCLUSION

Acceptance of CW recommendations to limit overuse may be enhanced by quantitative data on consequences and costs of surveillance imaging, supplemented by qualitative data on patient and physician attitudes.

Imaging Surveillance of Limited-stage Classic Hodgkin Lymphoma Patients After PET-CT-documented First Remission

INTRODUCTION

Early stage Hodgkin lymphoma (ESHL) is highly curable; however, 10% to 15% of patients experience relapse. We examined the utilization of follow-up imaging for patients with ESHL who achieved a metabolic complete response after upfront therapy.

MATERIALS AND METHODS

The records of adult patients treated at a single institution between 2003 and 2014 were reviewed. Positron emission tomography-computed tomography (PET-CT) and CT scan frequency was quantified during the 2 years following treatment and subsequent visits beyond 2 years.

RESULTS

The study cohort contained 179 patients. The median age was 31 years; bulky disease was present in 30%. ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) or AVD (doxorubicin, vinblastine, and dacarbazine) was given in 97%; 75% received radiation therapy. At a median follow-up of 6.9 years, the 5-year progression-free and overall survival rates were 93.7% and 98.1%, respectively. Relapse occurred in 5% (n = 9) of patients at a median of 9.1 months (range, 4.6-27.2 months) from therapy. Two patients presented with symptoms prompting imaging in follow-up. Within 2 years after therapy, 376 PET-CT scans and 3325 CT scans were performed, yielding an average of 2.1 PET-CTs and 18.6 CTs per patient. Of the initial 179 patients, 113 had follow-up conducted beyond 2 years post-therapy; an average of 2.7 PET-CTs and 33.2 CTs were performed. In the 2-year post-therapy period, 463 scans were performed per relapse detected.

CONCLUSION

In this cohort of patients with ESHL who responded completely to frontline therapy, the relapse rate was low. Routine imaging surveillance lacks clinical benefit in this patient population.

Interim PET-results for prognosis in adults with Hodgkin lymphoma: a systematic review and meta-analysis of prognostic factor studies

BACKGROUND

Hodgkin lymphoma (HL) is one of the most common haematological malignancies in young adults and, with cure rates of 90%, has become curable for the majority of individuals. Positron emission tomography (PET) is an imaging tool used to monitor a tumour's metabolic activity, stage and progression. Interim PET during chemotherapy has been posited as a prognostic factor in individuals with HL to distinguish between those with a poor prognosis and those with a better prognosis. This distinction is important to inform decision-making on the clinical pathway of individuals with HL.

OBJECTIVES

To determine whether in previously untreated adults with HL receiving first-line therapy, interim PET scan results can distinguish between those with a poor prognosis and those with a better prognosis, and thereby predict survival outcomes in each group.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and conference proceedings up until April 2019. We also searched one trial registry (ClinicalTrials.gov).

SELECTION CRITERIA

We included retrospective and prospective studies evaluating interim PET scans in a minimum of 10 individuals with HL (all stages) undergoing first-line therapy. Interim PET was defined as conducted during therapy (after one, two, three or four treatment cycles). The minimum follow-up period was at least 12 months. We excluded studies if the trial design allowed treatment modification based on the interim PET scan results.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form according to the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Two teams of two review authors independently screened the studies, extracted data on overall survival (OS), progression-free survival (PFS) and PET-associated adverse events (AEs), assessed risk of bias (per outcome) according to the Quality in Prognosis Studies (QUIPS) tool, and assessed the certainty of the evidence (GRADE). We contacted investigators to obtain missing information and data.

MAIN RESULTS

Our literature search yielded 11,277 results. In total, we included 23 studies (99 references) with 7335 newly-diagnosed individuals with classic HL (all stages). Participants in 16 studies underwent (interim) PET combined with computed tomography (PET-CT), compared to PET only in the remaining seven studies. The standard chemotherapy regimen included ABVD (16) studies, compared to BEACOPP or other regimens (seven studies). Most studies (N = 21) conducted interim PET scans after two cycles (PET2) of chemotherapy, although PET1, PET3 and PET4 were also reported in some studies. In the meta-analyses, we used PET2 data if available as we wanted to ensure homogeneity between studies. In most studies interim PET scan results were evaluated according to the Deauville 5-point scale (N = 12). Eight studies were not included in meta-analyses due to missing information and/or data; results were reported narratively. For the remaining studies, we pooled the unadjusted hazard ratio (HR). The timing of the outcome measurement was after two or three years (the median follow-up time ranged from 22 to 65 months) in the pooled studies. Eight studies explored the independent prognostic ability of interim PET by adjusting for other established prognostic factors (e.g. disease stage, B symptoms). We did not pool the results because the multivariable analyses adjusted for a different set of factors in each study. Overall survival Twelve (out of 23) studies reported OS. Six of these were assessed as low risk of bias in all of the first four domains of QUIPS (study participation, study attrition, prognostic factor measurement and outcome measurement). The other six studies were assessed as unclear, moderate or high risk of bias in at least one of these four domains. Four studies were assessed as low risk, and eight studies as high risk of bias for the domain other prognostic factors (covariates). Nine studies were assessed as low risk, and three studies as high risk of bias for the domain 'statistical analysis and reporting'. We pooled nine studies with 1802 participants. Participants with HL who have a negative interim PET scan result probably have a large advantage in OS compared to those with a positive interim PET scan result (unadjusted HR 5.09, 95% confidence interval (CI) 2.64 to 9.81, I² = 44%, moderate-certainty evidence). In absolute values, this means that 900 out of 1000 participants with a negative interim PET scan result will probably survive longer than three years compared to 585 (95% CI 356 to 757) out of 1000 participants with a positive result. Adjusted results from two studies also indicate an independent prognostic value of interim PET scan results (moderate-certainty evidence). Progression-free survival Twenty-one studies reported PFS. Eleven out of 21 were assessed as low risk of bias in the first four domains. The remaining were assessed as unclear, moderate or high risk of bias in at least one of the four domains. Eleven studies were assessed as low risk, and ten studies as high risk of bias for the domain other prognostic factors (covariates). Eight studies were assessed as high risk, thirteen as low risk of bias for statistical analysis and reporting. We pooled 14 studies with 2079 participants. Participants who have a negative interim PET scan result may have an advantage in PFS compared to those with a positive interim PET scan result, but the evidence is very uncertain (unadjusted HR 4.90, 95% CI 3.47 to 6.90, I² = 45%, very low-certainty evidence). This means that 850 out of 1000 participants with a negative interim PET scan result may be progression-free longer than three years compared to 451 (95% CI 326 to 569) out of 1000 participants with a positive result. Adjusted results (not pooled) from eight studies also indicate that there may be an independent prognostic value of interim PET scan results (low-certainty evidence). PET-associated adverse events No study measured PET-associated AEs.

AUTHORS' CONCLUSIONS

This review provides moderate-certainty evidence that interim PET scan results predict OS, and very low-certainty evidence that interim PET scan results predict progression-free survival in treated individuals with HL. This evidence is primarily based on unadjusted data. More studies are needed to test the adjusted prognostic ability of interim PET against established prognostic factors.

Histological transformation in malignant lymphoma: a possible role of PET/CT and circulating tumor DNA as noninvasive diagnostic tools

Introduction: Transformation is a multi-step event wherein indolent lymphomas, such as follicular lymphomas, are converted into an aggressive subtype, such as diffuse large B-cell lymphoma. This process progresses not only through mutations in several of the causative genes, such as TP53, CDKN2A/B, or MYC, but also through epigenetic or micro-environmental changes. Excisional biopsy is recommended when transformation is clinically suspected.Areas covered: The authors summarized the current knowledge regarding the clinicopathological and molecular features of transformed lymphomas and discussed the relevance of re-biopsy in the diagnosis of transformation, comparing it with noninvasive diagnostic tools [fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) and circulating tumor DNA (ctDNA) analysis].Expert opinion: Pathological confirmation by biopsy is considered the golden standard for diagnosis and is indispensable for determining subsequent treatment strategies. The potential weakness of this approach is its invasiveness and the unavailability of pathological findings outside the biopsied areas. In the context of relapse, PET/CT is used mainly for the selection of the best suitable biopsy site, while ctDNA has the potential for detecting systemic genomic changes associated with relapse before clinical presentation. Future investigations should be focused on combining biopsies with new technologies for an early and accurate diagnosis of transformation.

Interim PET-results for prognosis in adults with Hodgkin lymphoma: a systematic review and meta-analysis of prognostic factor studies

BACKGROUND

Hodgkin lymphoma (HL) is one of the most common haematological malignancies in young adults and, with cure rates of 90%, has become curable for the majority of individuals. Positron emission tomography (PET) is an imaging tool used to monitor a tumour's metabolic activity, stage and progression. Interim PET during chemotherapy has been posited as a prognostic factor in individuals with HL to distinguish between those with a poor prognosis and those with a better prognosis. This distinction is important to inform decision-making on the clinical pathway of individuals with HL.

OBJECTIVES

To determine whether in previously untreated adults with HL receiving first-line therapy, interim PET scan results can distinguish between those with a poor prognosis and those with a better prognosis, and thereby predict survival outcomes in each group.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and conference proceedings up until April 2019. We also searched one trial registry (ClinicalTrials.gov).

SELECTION CRITERIA

We included retrospective and prospective studies evaluating interim PET scans in a minimum of 10 individuals with HL (all stages) undergoing first-line therapy. Interim PET was defined as conducted during therapy (after one, two, three or four treatment cycles). The minimum follow-up period was at least 12 months. We excluded studies if the trial design allowed treatment modification based on the interim PET scan results.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form according to the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Two teams of two review authors independently screened the studies, extracted data on overall survival (OS), progression-free survival (PFS) and PET-associated adverse events (AEs), assessed risk of bias (per outcome) according to the Quality in Prognosis Studies (QUIPS) tool, and assessed the certainty of the evidence (GRADE). We contacted investigators to obtain missing information and data.

MAIN RESULTS

Our literature search yielded 11,277 results. In total, we included 23 studies (99 references) with 7335 newly-diagnosed individuals with classic HL (all stages).Participants in 16 studies underwent (interim) PET combined with computed tomography (PET-CT), compared to PET only in the remaining seven studies. The standard chemotherapy regimen included ABVD (16) studies, compared to BEACOPP or other regimens (seven studies). Most studies (N = 21) conducted interim PET scans after two cycles (PET2) of chemotherapy, although PET1, PET3 and PET4 were also reported in some studies. In the meta-analyses, we used PET2 data if available as we wanted to ensure homogeneity between studies. In most studies interim PET scan results were evaluated according to the Deauville 5-point scale (N = 12).Eight studies were not included in meta-analyses due to missing information and/or data; results were reported narratively. For the remaining studies, we pooled the unadjusted hazard ratio (HR). The timing of the outcome measurement was after two or three years (the median follow-up time ranged from 22 to 65 months) in the pooled studies.Eight studies explored the independent prognostic ability of interim PET by adjusting for other established prognostic factors (e.g. disease stage, B symptoms). We did not pool the results because the multivariable analyses adjusted for a different set of factors in each study.Overall survivalTwelve (out of 23) studies reported OS. Six of these were assessed as low risk of bias in all of the first four domains of QUIPS (study participation, study attrition, prognostic factor measurement and outcome measurement). The other six studies were assessed as unclear, moderate or high risk of bias in at least one of these four domains. Nine studies were assessed as high risk, and three studies as moderate risk of bias for the domain study confounding. Eight studies were assessed as low risk, and four studies as high risk of bias for the domain statistical analysis and reporting.We pooled nine studies with 1802 participants. Participants with HL who have a negative interim PET scan result probably have a large advantage in OS compared to those with a positive interim PET scan result (unadjusted HR 5.09, 95% confidence interval (CI) 2.64 to 9.81, I² = 44%, moderate-certainty evidence). In absolute values, this means that 900 out of 1000 participants with a negative interim PET scan result will probably survive longer than three years compared to 585 (95% CI 356 to 757) out of 1000 participants with a positive result.Adjusted results from two studies also indicate an independent prognostic value of interim PET scan results (moderate-certainty evidence).Progression-free survival Twenty-one studies reported PFS. Eleven out of 21 were assessed as low risk of bias in the first four domains. The remaining were assessed as unclear, moderate or high risk of bias in at least one of the four domains. Eleven studies were assessed as high risk, nine studies as moderate risk and one study as low risk of bias for study confounding. Eight studies were assessed as high risk, three as moderate risk and nine as low risk of bias for statistical analysis and reporting.We pooled 14 studies with 2079 participants. Participants who have a negative interim PET scan result may have an advantage in PFS compared to those with a positive interim PET scan result, but the evidence is very uncertain (unadjusted HR 4.90, 95% CI 3.47 to 6.90, I² = 45%, very low-certainty evidence). This means that 850 out of 1000 participants with a negative interim PET scan result may be progression-free longer than three years compared to 451 (95% CI 326 to 569) out of 1000 participants with a positive result.Adjusted results (not pooled) from eight studies also indicate that there may be an independent prognostic value of interim PET scan results (low-certainty evidence).PET-associated adverse eventsNo study measured PET-associated AEs.

AUTHORS' CONCLUSIONS

This review provides moderate-certainty evidence that interim PET scan results predict OS, and very low-certainty evidence that interim PET scan results predict progression-free survival in treated individuals with HL. This evidence is primarily based on unadjusted data. More studies are needed to test the adjusted prognostic ability of interim PET against established prognostic factors.

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.

Proportion of false-positive follow-up FDG-PET scans in lymphoma: Systematic review and meta-analysis

This study aimed to assess the false-positive proportion of follow-up ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in lymphoma patients who initially achieved an end-of-treatment complete remission, using biopsy as reference standard. Medline was searched for original studies, studies were methodologically evaluated and results were meta-analytically summarized. Proportion of false-positive results ranged between 9.5%-90.0%, with a weighted summary proportion (random effects) of 42.9% (95% confidence interval [CI]: 29.0%-58.0%). A separate subgroup analysis in symptomatic patients only again revealed a relatively high summary proportion of false-positive follow-up FDG-PET of 37.5% (random effects). In conclusion, the false-positive proportion of follow-up FDG-PET in lymphoma patients who initially achieved an end-of-treatment complete remission is high and remains high when a combination of clinical symptoms and follow-up FDG-PET is used. Therefore, biopsy remains compulsory and follow-up FDG-PET alone may be regarded as unreliable to define progression-free survival.

Do Deauville Scores Improve the Clinical Utility of End-of-Therapy FDG PET Scans for Pediatric Hodgkin Lymphoma?

OBJECTIVE

The purpose of this study was to evaluate the clinical utility of Deauville scores in interpretation of end-of-chemotherapy FDG PET scans.

CONCLUSION

Deauville scores improve the clinical utility of end-of-chemotherapy PET, as evidenced by an increase in positive predictive value to 72.7% from 44.4% on the basis of report alone. The negative predictive value remains greater than 95%.

FDG-PET/CT in the management of lymphomas: current status and future directions

FDG-PET/CT is the current state-of-the-art imaging in lymphoma and plays a central role in treatment decisions. At diagnosis, accurate staging is crucial for appropriate therapy selection: FDG-PET/CT can identify areas of lymphoma missed by CT alone and avoid under-treatment of patients with advanced disease stage who would have been misclassified as having limited stage disease by CT. Particularly in Hodgkin lymphoma, positive interim FDG-PET/CT scans are adversely prognostic for clinical outcomes and can inform PET-adapted treatment strategies, but such data are less consistent in diffuse large B-cell lymphoma. The use of quantitative FDG-PET/CT metrics using metabolic tumour volume, possibly in combination with other biomarkers, may better define prognostic subgroups and thus facilitate better treatment selection. After chemotherapy, FDG-PET/CT response is predictive of outcome and may identify a subgroup who benefit from consolidative radiotherapy. Novel therapies, in particular immunotherapies, exhibit different response patterns than conventional chemotherapy, which has led to modified response criteria that take into account the risk of transient pseudo-progression. In relapsed lymphoma, FDG-PET/CT after second-line therapy and prior to high-dose therapy is also strongly associated with outcome and may be used to guide intensity of salvage therapy in relapsed Hodgkin lymphoma. Currently, FDG-PET/CT has no role in the routine follow-up after complete metabolic response to therapy, but it remains a powerful tool for excluding relapse if patients develop clinical features suggestive of disease relapse. In conclusion, FDG-PET/CT plays major roles in the various phases of management of lymphoma and constitutes a step towards the pursuit of personalized treatment.

2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography in primary extranodal lymphomas: treatment response evaluation and prognosis

BACKGROUND

We evaluated the role of [18F]FDG PET/CT in tumor response assessment and prognosis of primary extranodal lymphoma (PEL) patients.

METHODS

We examined retrospectively, 56 PEL patients: 31 with aggressive diffuse large B cell lymphoma (DLBCL) and 25 with indolent lymphoma (20 mucosa-associated lymphoid tissue lymphoma and five follicular lymphoma). All patients had undergone [18F]FDG PET/CT at diagnosis (PET-I) and 50 of them also after therapy (PET-II). Moreover, 52 patients were subjected to a mean follow-up period of 76 months.

RESULTS

PET-I was positive in 50 (89%) patients (mean SUVmax 10.3±6.7). In the assessment of tumor response, according to Lugano classification, 45 patients showed complete metabolic response (CMR), four patients had partial metabolic response (PMR) and one had progressive metabolic disease (PMD). Based on 66% ΔSUVmax cut-off, among CMR patients, 41 showed a ΔSUVmax>66% whereas among non-responders, four patients showed a ΔSUVmax<66%. At follow-up, univariate analysis showed that age, performance status, prognostic index, ΔSUVmax and Lugano classification predicted progression-free survival (PFS) (P<0.05), while, performance status, prognostic index, ΔSUVmax and Lugano classification predicted overall survival (OS) (P<0.05). At multivariate analysis only Lugano classification was retained in the model for prediction of both PFS (P<0.05) and OS (P<0.05). By Kaplan-Meier analysis and log-rank testing both PFS and OS were significantly better in patients in CMR as compared to patients in PMR or PMD according to Lugano classification (P<0.01).

CONCLUSIONS

[18F]FDG PET/CT represents a useful tool in the detection of disease response and in the evaluation of outcome in PEL patients.

Post-treatment surveillance imaging in lymphoma

Appropriate post-treatment management of patients with lymphoma has been controversial, with imaging frequently performed as post-treatment surveillance. The goal of post-treatment imaging is to identify relapse prior to clinical symptoms, when the burden of disease is lower and the possibility of effective salvage therapy and cure are greater. However, little data exist to support the performance of surveillance imaging after completion of treatment, with the vast majority of studies suggesting there is no clinical benefit to surveillance imaging in asymptomatic patients. Ongoing efforts seek to identify a subset of patients with a higher risk of relapse that might benefit from surveillance imaging, though financial and other costs associated with imaging are non-negligible and must be considered. Here we summarize the current data regarding post-treatment surveillance imaging in lymphoma.

Young adults diagnosed with Hodgkin lymphoma are at risk of relapsing late: a comprehensive analysis of late relapse in Hodgkin lymphoma

PURPOSE

Majority of relapses in Hodgkin lymphoma (HL) occur within 3 years after initial treatment, late relapses (LR), happening 5 or more years after first diagnosis is rare events. Neither clinical characteristics, risk factors, nor optimal treatment is well described for LR patients. Our aim was to provide a comprehensive analysis on the LR of HL to outline a patient population at risk of relapsing late.

PATIENTS AND METHODS

637 HL patients were treated at the University of Debrecen between 1981 and 2010. Patient data was evaluated retrospectively. Survival analysis was performed using the Kaplan-Meier method and odds ratios (OR) were identified by binary logistic regression models.

RESULTS

With a median observational time of 9.08 years 584 (91%) HL patients achieved complete remission (CR) after first line treatment. Relapse occurred in 176 (28%) patients, 26 (4%) of them 5 or more years after first diagnosis. With multivariable analysis, initial diagnosis before the age of 24 (p < 0.001), initial presentation between 1981 and 1990 or 1991-2000 (p = 0.025 and p = 0.023, respectively) and first line treatment with radiotherapy only (p = 0.034) were identified as independent risk factors for LR. We observed a significantly impaired OS for patients with early relapse HL compared to those in long-term remission or experiencing LR (p < 0.001).

CONCLUSION

Late relapse of HL presents with clinical characteristics very similar to primary disease and appears to have a good prognosis. First diagnosis in childhood or young adulthood and first line treatment before the ABVD era increases the risk of relapsing late.

PET-CT in Staging, Response Evaluation, and Surveillance of Lymphoma

OPINION STATEMENT

Lymphoma represents a broad spectrum of diseases with diverse biology, clinical behavior, and imaging features. Functional imaging with 18-F-fluorodeoxyglucose (FDG)-positron emission tomography combined with computed tomography (PET-CT) is widely recognized as the most sensitive and specific imaging modality for patients with lymphoma and is used as part of staging, response evaluation, and surveillance in patients with Hodgkin (HL) and non-Hodgkin lymphoma (NHL). Recent efforts at standardizing the conduct and consensus interpretation of PET-CT have facilitated its use in patients on clinical studies and beyond. The role of PET-CT has been affirmed in some clinical situations, such as staging and end-of-treatment evaluation in Hodgkin lymphoma and diffuse large B cell lymphoma (DLBCL), and in the evaluation of aggressive transformation of an indolent lymphoma. However, the role of functional imaging in other histologies and clinical settings is not as clear given the higher rate of false positive results and the costs inherent to PET-CT. There is little evidence to suggest its utility or impact on outcome in most indolent lymphomas, or in the setting of post-treatment surveillance. In addition, there remains controversy about the value of PET-CT in early response assessment during active therapy, particularly in DLBCL. This review will evaluate the evidence surrounding the role of PET-CT in staging, response evaluation and surveillance of Hodgkin and non-Hodgkin lymphoma.

Surveillance Scans in Lymphoma: Friend or Foe?

OPINION STATEMENT

Advancements in the treatment of lymphoma over the last few decades have allowed more patients to achieve a remission after the completion of therapy. Due to the improvement in response rates, methods to detect recurrence early and accurately during follow-up, especially in patients with potential curable aggressive lymphomas, are a key. Observation has always involved close clinical follow-up with the use of physical exams and routine labs, but rapid changes in technology have allowed CT scans, PET scans, and MRIs to become an integral part of managing patients with lymphoma. While the utility of scans in initial staging and immediately after completion of therapy is well established, the use of these imaging modalities for monitoring recurrence in lymphoma patients is still controversial. Patient advocacy groups and other regulatory committees have questioned the frequency and in some cases even the need for these tests in patients without evidence of active disease given the concern for radiation-associated health risks. Additionally, the extent to which this form of testing impacts the psyche of our patients is not completely known. Given the numerous questions raised about the benefits, safety, and cost-effectiveness of CT imaging, firm guidelines are needed at this time in standard practice and within our clinical trials to limit the use of surveillance imaging. Such efforts are expected to improve the utility of these scans in asymptomatic patients, reduce healthcare costs, and reduce patient exposure to radiation.

The role of FDG-PET in Hodgkin lymphoma

18-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) is currently the most valuable imaging technique in Hodgkin lymphoma. Since its first use in lymphomas in the 1990s, it has become the gold standard in the staging and end-of-treatment remission assessment in patients with Hodgkin lymphoma. The possibility of using early (interim) PET during first-line therapy to evaluate chemosensitivity and thus personalize treatment at this stage holds great promise, and much attention is now being directed toward this goal. With high probability, it is believed that in the near future, the result of interim PET-CT would serve as a compass to optimize treatment. Also the role of PET in pre-transplant assessment is currently evolving. Much controversy surrounds the possibility of detecting relapse after completed treatment with the use of PET in surveillance in the absence of symptoms suggestive of recurrence and the results of published studies are rather discouraging because of low positive predictive value. This review presents current knowledge about the role of 18-FDG-PET/CT imaging at each point of management of patients with Hodgkin lymphoma.

The clinical utility of FDG PET/CT among solid organ transplant recipients suspected of malignancy or infection

PURPOSE

Solid organ transplant (SOT) recipients are at high risk of developing infections and malignancies. 18F-FDG PET/CT may enable timely detection of these diseases and help to ensure early intervention. We aimed to describe the clinical utility of FDG PET/CT in consecutive, diagnostic unresolved SOT recipients transplanted from January 2004 to May 2015.

METHODS

Recipients with a post-transplant FDG PET/CT performed as part of diagnostic work-up were included. Detailed chart reviews were done to extract relevant clinical information and determine the final diagnosis related to the FDG PET/CT. Based on á priori defined criteria and the final diagnosis, results from each scan were classified as true or false, and diagnostic values determined.

RESULTS

Among the 1,814 recipients in the cohort, 145 had an FDG PET/CT performed; 122 under the indication of diagnostically unresolved symptoms with a suspicion of malignancy or infection. The remaining (N = 23) had an FDG PET/CT to follow-up on a known disease or to stage a known malignancy. The 122 recipients underwent a total of 133 FDG PET/CT scans performed for a suspected malignancy (66 %) or an infection (34 %). Sensitivity, specificity, and positive and negative predictive values of the FDG PET/CT in diagnosing these conditions were 97, 84, 87, and 96 %, respectively.

CONCLUSION

FDG PET/CT is an accurate diagnostic tool for the work-up of diagnostic unresolved SOT recipients suspected of malignancy or infection. The high sensitivity and NPV underlines the potential usefulness of PET/CT for excluding malignancy or focal infections in this often complex clinical situation.

Evaluating surveillance imaging for diffuse large B-cell lymphoma and Hodgkin lymphoma

Up to 50% of patients with Hodgkin lymphoma and diffuse large B-cell lymphoma will relapse, requiring additional therapy. Although surveillance imaging is commonly performed in clinical practice, its ability to identify asymptomatic relapses and improve survival for patients is not well defined. We evaluated the surveillance imaging role in relapse detection and reviewed its impact on survival for relapsed patients, and found that current imaging approaches do not detect most relapses prior to clinical signs and symptoms or improve survival.

PET/CT in the Evaluation of Relapsed or Refractory Hodgkin Lymphoma

18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) has been the most important advance in the assessment of Hodgkin lymphoma (HL) since the introduction of computed tomography (CT). In the frontline management of HL, FDG-PET combined with low-dose CT has emerged as the modality of choice for staging and treatment response assessment. Substantial data have accumulated over the past several years supporting the use of PET/CT in the evaluation and management of relapsed or refractory HL, as well. In this article, we review the role of PET/CT after the frontline treatment of HL, as well as the prognostic utility of PET/CT before autologous and allogeneic stem cell transplantation. We also review the use of PET/CT as a part of response-adapted treatment strategies in relapsed or refractory HL and implications for current and future clinical practice.

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.

A pilot study of the value of 18F-fluoro-deoxy-thymidine PET/CT in predicting viable lymphoma in residual 18F-FDG avid masses after completion of therapy

BACKGROUND

Despite its success in diagnosing and staging lymphoma, F-FDG PET/CT can be falsely positive in areas of posttreatment inflammation. 3'-F-fluoro-3'-deoxy-l-thymidine (F-FLT) is a structural analog of the DNA constituent thymidine; its uptake correlates with cellular proliferation. This pilot study evaluates the ability of F-FLT PET/CT to distinguish viable lymphoma from posttreatment inflammatory changes in F-FDG avid residual masses.

METHODS

Twenty-one patients with lymphoma with at least 1 F-FDG avid residual mass after therapy underwent F-FLT PET/CT imaging. F-FDG and F-FLT uptake values were compared, including quantitative pharmacokinetic parameters extracted from the F-FLT time activity curves generated from dynamic data using graphical and nonlinear compartmental modeling.

RESULTS

The true nature of the residual mass was confirmed by biopsy in 12 patients (8 positive and 4 negative for viable lymphoma and by follow-up CT and/or repeat F-FDG PET/CT imaging over 1 year); among the remaining 9 patients, 7 lesions resolved or decreased and 2 showed growth indicative of lymphoma. F-FLT PET SUVest.max was significantly higher in tumors than in benign lesions (5.5 [2.2] vs 1.7 [0.6]; P < 0.0001), whereas the difference in F-FDG SUVs was not significant (malignant, 7.8 [3.8] vs benign, 5.4 [2.4]; P = 0.11). All of the benign lesions had an F-FLT SUVest.max of less than 3.0.

CONCLUSIONS

F-FLT shows improved specificity over F-FDG in distinguishing residual lymphoma from posttreatment inflammation and may be useful in the evaluation of patients with residual F-FDG-positive masses after completing therapy.

[Usefulness of Clinicobiological Data Obtained Prior to Cervical Lymph Node Biopsy]

INTRODUCTION

We commonly use data obtained prior to cervical lymph node biopsy for the diagnosis of malignant lymphoma. Based on such data, we can confirm whether a biopsy should be performed in some cases. Currently, the parameters used to indicate a presurgery examination prior to biopsy have been very few. So, we retrospectively analyzed cases of cervical lymph node biopsy. Moreover, we examined the usefulness of clinicobiological data obtained prior to cervical lymph node biopsy to evaluate various factors related to the diagnosis of malignant lymphoma.

METHODS

This study included 77 patients for whom the initial diagnostic impression was malignant lymphoma before surgery. Of the 77 cases, 40 were diagnosed as having malignant lymphoma and 37 were diagnosed as having non-malignant lymphoma. We performed a case-controlled study to evaluate the differences in clinicobiological data between malignant and non-malignant lymphoma in terms of the following parameters: (1) age, (2) sex, (3) number of white blood cells, (4) white blood cell lymphocyte count, (5) percentage of white blood cell lymphocytes, (6) percentage of eosinophils (%), (7) percentage of monocytes (%), (8) atypical lymphocytes (%), (9) hemoglobin level, (10) lactate dehydrogenase level, (11) C-reactive protein level, (12) soluble interleukin-2 receptor (IL-2R) level, and (13) cytological findings. We used multivariate and univariate analyses to study the data statistically.

RESULTS

The following 5 factors were found to be significant in a Wilcoxon t-test for malignant lymphoma: percentage of white blood cell lymphocytes, sIL-2R level, age, white blood cell lymphocyte count, and cytological findings; these factors were also significant when examined using a Pearson χ2 test. The other factors did not differ significantly between the malignant and non-malignant lymphomas. The percentage of white blood cell lymphocytes and the cytological findings were identified as significant independent factors for the diagnosis of malignant lymphoma in a multivariate analysis, whereas the other factors were not found to be significant.

CONCLUSION

Based on the results of the univariate and multivariate analyses performed in the present study, the decline in the percentage of white blood cell lymphocytes and the cytological findings obtained prior to cervical lymph node biopsy are significant indicators of malignant lymphoma.

Baseline and ongoing PET-derived factors predict detrimental effect or potential utility of 18F-FDG PET/CT (FDG-PET/CT) performed for surveillance in asymptomatic lymphoma patients in first remission

PURPOSE

To identify both clinical and FDG PET/CT-derived factors predicting the occurrence of relapse, or conversely, the likelihood of false positive findings in surveillance FDG-PET/CT studies (PETsv).

METHODS

The study included 149 asymptomatic patients with Hodgkin's lymphoma (HL) (n = 55) or diffuse large B cell lymphoma (DLBCL) (n = 94) in first remission. PETSv studies were performed 12, 18, 24 and 36 months thereafter. Logistic regression analysis was performed to identify clinical and imaging-derived predictors of either PET-detected relapse or false-positive (FP) results. Tested clinical variables were: 1) age, 2) HL vs. DLBCL, 3) stage of disease, 4) bulky disease, 5) previous radiotherapy. PET/CT-derived variables were: 1) maximum standardized uptake value at baseline, 2) size-incorporated maximum standardized uptake value (SIMaxSUV) at baseline, 3) positive interim PET(PET-2), 4) presence of hot spots likely to be unrelated to the disease in final PET, 5) residual non-FDG avid mass.

RESULTS

Accuracy was 88 % for PETsv1, 95 % for PETsv2, 95 % for PETsv3 and 91 % for PETsv4. However, PPV was relatively low in all PETsv. Best predictors of relapse were result of interim PET, HL versus NHL type, SIMaxSUV, age ≥ 60. Best predictors of FP were previous radiotherapy and hot spots unrelated to the disease in final PET.

CONCLUSIONS

The present study confirms the need of restricting the use of surveillance PET/CT to patients at high risk of relapse. Information derived from PET/CT performed at baseline (metabolic disease burden), in the course (PET2) and at the end of therapy (unrelated hot spots) can help to select high-risk patients and also to identify patients more likely to present equivocal findings at PETsv.

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.

Beyond PET/CT in Hodgkin lymphoma: a comprehensive review of the role of imaging at initial presentation, during follow-up and for assessment of treatment-related complications

Objective

The purpose of this article is to provide a comprehensive review of the role of imaging modalities other than PET/CT in the management of Hodgkin lymphoma (HL). PET/CT is the imaging modality of choice in the management of Hodgkin’s lymphoma (HL). However, imaging modalities other than PET/CT such as plain radiographs, ultrasound, CT, MRI and nuclear imaging can help in various stages of clinical management of HL, including the initial workup and post-treatment surveillance. Both CT and MRI help in detecting recurrences, treatment-related pulmonary, cardiovascular and abdominal complications as well as second malignancies. Familiarity with expected post-treatment changes and complications on surveillance images can help radiologists guide patient management. The purpose of this article is to provide a comprehensive review of the role of imaging modalities other than PET/CT in the management of Hodgkin lymphoma (HL).

Main Messages

• Surveillance of HL patients is usually performed with plain radiographs and CT.

• Follow-up imaging can depict normal post-treatment changes or treatment-related complications.

• Imaging is important for the timely detection of second malignancies in HL patients.

Very low utility of surveillance imaging in early-stage classic Hodgkin lymphoma treated with a combination of doxorubicin, bleomycin, vinblastine, and dacarbazine and radiation therapy

BACKGROUND

This study evaluated the need for surveillance imaging in early-stage classic Hodgkin lymphoma (cHL) after planned combined-modality therapy (CMT).

METHODS

Primary early-stage cHL patients who underwent CMT were included. Positron emission tomography (PET)/computed tomography (CT), CT, or both were performed at the initial staging, during or after chemotherapy, and for at least 2 years during follow-up. Imaging studies and medical records were reviewed to determine if and when relapse had occurred. Radiation doses and costs were also calculated from follow-up imaging.

RESULTS

The study included 78 patients with a median follow-up of 46 months; 85% of the patients had stage II disease (32% with bulky disease). Four of 77 interim PET scans were positive; none of these patients relapsed during follow-up, which ranged from 24 to 80 months. After a total of 466 follow-up imaging studies (91% with CT and 9% with PET/CT), no cHL relapse was detected. Eleven abnormal findings were noted on surveillance imaging: 9 were false-positives, and 2 were second primary malignancies. The average cumulative dose per patient from follow-up imaging was 107 mSv, which translated into an estimated lifetime excess cancer risk of 0.5%; the estimated total costs were $296,817 according to Medicare reimbursements.

CONCLUSIONS

Surveillance imaging with either CT or PET/CT can be omitted safely for early-stage cHL treated with a combination of doxorubicin, bleomycin, vinblastine, and dacarbazine and radiation therapy because the risk of relapse is extremely low. This observation also applies to patients with bulky disease. The elimination of surveillance imaging will also reduce healthcare expenses and cumulative radiation doses in these predominantly young patients.

Role of 2-Deoxy-2-[18F]-fluoro-d-glucose-PET/Computed Tomography in Lymphoma

The role of PET and PET/computed tomography (CT) has evolved significantly in the last few decades. 2-Deoxy-2-[18F]-fluoro-d-glucose (FDG)-PET/CT is now an integral part of the management of patients with lymphoma. FDG-PET/CT at the time of initial staging can help in appropriate staging of the patients. Both interim and end-of-therapy PETs have significant prognostic value in patients with Hodgkin lymphoma and aggressive non-Hodgkin lymphoma and more accurately assess for the presence of residual malignancy than anatomic imaging. The impact of interim FDG-PET/CT on risk-adapted strategies is an area of active investigation and the results of ongoing clinical trials will be informative.

Next-generation surveillance strategies for patients with lymphoma

While remission and cure rates for Hodgkin and non-Hodgkin lymphoma continue to improve, surveillance approaches remain controversial, especially in light of recent reports suggesting limited benefit for routine radiologic assessment. Routine cross-sectional imaging results in considerable patient expense and anxiety, and this approach does not clearly improve patient outcomes. Next-generation approaches including minimal residual disease detection may provide an opportunity to identify relapse early and intervene prior to progression of clinical disease. This review discusses the role of surveillance imaging in Hodgkin and non-Hodgkin lymphoma and provides an introduction to serologic assessment of minimal residual disease. Future studies will need to focus on the clinical application of minimal residual disease surveillance and its ability to predict relapse, treatment response and survival.

Durable remissions in a pivotal phase 2 study of brentuximab vedotin in relapsed or refractory Hodgkin lymphoma

We present response and survival outcomes of a pivotal phase 2 trial of the antibody-drug conjugate brentuximab vedotin in patients with relapsed/refractory Hodgkin lymphoma following autologous stem cell transplant (N = 102) after a median observation period of approximately 3 years. Median overall survival and progression-free survival were estimated at 40.5 months and 9.3 months, respectively. Improved outcomes were observed in patients who achieved a complete remission (CR) on brentuximab vedotin, with estimated 3-year overall survival and progression-free survival rates of 73% (95% confidence interval [CI]: 57%, 88%) and 58% (95% CI: 41%, 76%), respectively, in this group (medians not reached). Of the 34 patients who obtained CR, 16 (47%) remain progression-free after a median of 53.3 months (range, 29.0 to 56.2 months) of observation; 12 patients remain progression-free without a consolidative allogeneic stem cell transplant. Younger age, good performance status, and lower disease burden at baseline were characteristic of patients who achieved a CR and were favorable prognostic factors for overall survival. These results suggest that a significant proportion of patients who respond to brentuximab vedotin can achieve prolonged disease control. The trial was registered at www.clinicaltrials.gov as #NCT00848926.

ACR appropriateness criteria follow-up of Hodgkin lymphoma

The main objectives of follow-up studies after completion of treatment for Hodgkin lymphoma are detection of recurrence for salvage therapy and monitoring for sequelae of treatment. The focus of the follow-up shifts, with time after treatment, from detection of recurrence to long-term sequelae. A majority of recurrence is detected by history and physical examination. The yield for routine imaging studies and blood tests is low. Although routine surveillance CT scan can detect recurrence not detected by history and physical examination, its benefit in ultimate survival and cost-effectiveness is not well defined. Although PET scan is a useful tool in assessing response to treatment, its routine use for follow-up is not recommended. Long-term sequelae of treatment include secondary malignancy, cardiovascular disease, pneumonitis, reproductive dysfunction, and hypothyroidism. Follow-up strategies for these sequelae need to be individualized, as their risks in general depend on the dose and volume of radiation to these organs, chemotherapy, age at treatment, and predisposing factors for each sequela. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is either lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Role of routine imaging in detecting recurrent lymphoma: A review of 258 patients with relapsed aggressive non-Hodgkin and Hodgkin lymphoma

After first-line therapy, patients with Hodgkin lymphoma (HL) and aggressive non-HL are followed up closely for early signs of relapse. The current follow-up practice with frequent use of surveillance imaging is highly controversial and warrants a critical evaluation. Therefore, a retrospective multicenter study of relapsed HL and aggressive non-HL (nodal T-cell and diffuse large B-cell lymphomas) was conducted. All included patients had been diagnosed during the period 2002-2011 and relapsed after achieving complete remission on first-line therapy. Characteristics and outcome of imaging-detected relapses were compared with other relapses. A total of 258 patients with recurrent lymphoma were included in the study. Relapse investigations were initiated outside preplanned visits in 52% of the patients. Relapse detection could be attributed to patient-reported symptoms alone or in combination with abnormal blood tests or physical examination in 64% of the patients. Routine imaging prompted relapse investigations in 27% of the patients. The estimated number of routine scans per relapse was 91-255 depending on the lymphoma subtype. Patients with imaging-detected relapse had lower disease burden (P = 0.045) and reduced risk of death following relapse (hazard ratio = 0.62, P = 0.02 in multivariate analysis). Patient-reported symptoms are still the most common factor for detecting lymphoma relapse and the high number of scans per relapse calls for improved criteria for use of surveillance imaging. However, imaging-detected relapse was associated with lower disease burden and a possible survival advantage. The future role of routine surveillance imaging should be defined in a randomized trial.