Pre-transplant positron emission tomography (PET) using fluorine-18-fluoro-deoxyglucose (FDG) predicts outcome in patients treated with high-dose chemotherapy and autologous stem cell transplantation for non-Hodgkin's lymphoma

Management of relapsed or refractory large B-cell lymphoma: A British Society for Haematology Guideline

Time to progression is the strongest predictor of outcome in relapsed diffuse large B-cell lymphoma. Second-line treatment with chimeric antigen receptor (CAR) T-cell therapy is recommended for patients with progression within 12 months of first-line chemoimmunotherapy. In patients with late relapse, platinum-based chemotherapy followed by high-dose chemotherapy with autologous stem cell rescue is recommended. In second relapse, CAR T-cell or CD3xCD20 bispecific antibody therapy is recommended in eligible patients. Other treatment options are available for less fit patients. Specific recommendations are made on diagnostic immunohistochemistry, bendamustine use and bridging to CAR T-cell therapy.

Clinical Utility of 18Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) in Multivisceral Transplant Patients

Multivisceral transplant (MVTx) refers to a composite graft from a cadaveric donor, which often includes the liver, the pancreaticoduodenal complex, and small intestine transplanted en bloc. It remains rare and is performed in specialist centres. Post-transplant complications are reported at a higher rate in multivisceral transplants because of the high levels of immunosuppression used to prevent rejection of the highly immunogenic intestine. In this study, we analyzed the clinical utility of 28 ¹⁸F-FDG PET/CT scans in 20 multivisceral transplant recipients in whom previous non-functional imaging was deemed clinically inconclusive. The results were compared with histopathological and clinical follow-up data. In our study, the accuracy of ¹⁸F-FDG PET/CT was determined as 66.7%, where a final diagnosis was confirmed clinically or via pathology. Of the 28 scans, 24 scans (85.7%) directly affected patient management, of which 9 were related to starting of new treatments and 6 resulted in an ongoing treatment or planned surgery being stopped. This study demonstrates that ¹⁸F-FDG PET/CT is a promising technique in identifying life-threatening pathologies in this complex group of patients. It would appear that ¹⁸F-FDG PET/CT has a good level of accuracy, including for those MVTx patients suffering from infection, post-transplant lymphoproliferative disease, and malignancy.

A picture is worth a thousand words: a history of diagnostic imaging for lymphoma

The journey from early drawings of Thomas Hodgkin's patients to deep learning with radiomics in lymphoma has taken nearly 200 years, and in many ways, it parallels the journey of medicine. By tracing the history of imaging in clinical lymphoma practice, we can better understand the motivations for current imaging practices. The earliest imaging modalities of the 2D era each had varied, site-dependent sensitivity, and the improved accuracy of imaging studies allowed new diagnostic and therapeutic techniques. First, we review the initial imaging technologies that were applied to understand lymphoma spread and achieve practical guidance for the earliest lymphoma treatments. Next, in the 3D era, we describe how anatomical imaging advances replaced and complemented conventional modalities. Afterward, we discuss how the PET era scans were used to understand response of tumors to treatment and risk stratification. Finally, we discuss the emergence of radiomics as a promising area of research in personalized medicine. We are now able to identify involved lymph nodes and body sites both before and after treatment to offer patients improved treatment outcomes. As imaging methods continue to improve sensitivity, we will be able to use personalized medicine approaches to give targeted and highly focused therapies at even earlier time points, and ideally, we can obtain long-term disease control and cures for lymphomas.

Diffuse Large B-Cell Lymphoma in the Era of Precision Oncology: How Imaging Is Helpful

Diffuse large B cell lymphoma (DLBCL) is the most common histological subtype of Non-Hodgkin's lymphoma. As treatments continues to evolve, so do imaging strategies, and positron emission tomography (PET) has emerged as the most important imaging tool to guide oncologists in the diagnosis, staging, response assessment, relapse/recurrence detection,and therapeutic decision making of DLBCL. Other imaging modalities including magnetic resonance imaging (MRI), computed tomography (CT), ultrasound, and conventional radiography are also used in the evaluation of lymphoma. MRI is useful for nervous system and musculoskeletal system involvement and is emerging as a radiation free alternative to PET/CT. This article provides a comprehensive review of both the functional and morphological imaging modalities, available in the management of DLBCL.

ESMO consensus conference on malignant lymphoma: general perspectives and recommendations for prognostic tools in mature B-cell lymphomas and chronic lymphocytic leukaemia

The European Society for Medical Oncology (ESMO) consensus conference on mature B-cell lymphomas and chronic lymphocytic leukaemia (CLL) was held on 20 June 2015 in Lugano, Switzerland, and included a multidisciplinary panel of 25 leading experts. The aim of the conference was to develop recommendations on critical subjects difficult to consider in detail in the ESMO Clinical Practice Guidelines. The following areas were identified: (i) the elderly patient, (ii) prognostic factors suitable for clinical use and (iii) the 'ultra-high-risk' group. Before the conference, the expert panel was divided into three working groups; each group focused on one of these areas in order to address four clinically relevant questions relating to that topic. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, each working group developed recommendations to address each of the four questions assigned to their group. These recommendations were then presented to the entire panel and a consensus was reached. This manuscript presents recommendations dedicated to the second area of interest, i.e. prognostic factors suitable for clinical use. The four topics [i.e. interim positron emission tomography (PET), TP53 mutations, cell of origin (COO) and minimal residual disease (MRD)] were primarily chosen because of the bulk of available data together with the lack of clear guidance regarding their use in clinical practice and within clinical trials. Results, including a summary of evidence supporting each recommendation, are detailed in this manuscript. The panel acknowledged that detection of TP53 inactivation by deletion or mutation in CLL should be implemented in clinical practice (level of evidence I, strength of recommendation A). Due to their potentially high prognostic value, at least in some lymphoma entities, implementation of interim PET, COO and MRD was highly recommended in the context of clinical trials. All expert panel members approved this final article.

The role of fluorine-18 fluorodeoxyglucose PET in prognosis evaluation for stem cell transplantation of lymphoma: a systematic review and meta-analysis

The role of fluorine-18 fluorodeoxyglucose PET (F-FDG PET) in prognostic evaluation of pre-stem cell transplantation (SCT) and post-SCT is still uncertain. A systematic review and meta-analysis were carried out to detect the prognostic power of F-FDG PET. 'PubMed', EMBASE, and Springer were searched for relevant articles. Subgroup analysis was carried out to evaluate the F-FDG PET in predicting the prognosis between Hodgkin lymphoma (HL) and non-Hodgkin lymphoma. Finally, 17 studies that included 1192 patients were eligible, 16 studies for progression-free survival (PFS) and 12 studies for overall survival (OS). For the pre-SCT PET or PET/computed tomography scan, the combined hazard ratios (HRs) of PET for PFS and OS were 2.32 and 2.64, respectively. Subgroup analysis showed that the HRs of PFS for HL and non-Hodgkin lymphoma were 3.28 and 2.00, respectively. For the post-SCT PET scan, the combined HR for PFS was 4.61. The sensitivity analysis showed that exlcusion of any single study had no significant effect on HR. We found that F-FDG PET was especially effective in predicting pre-STC and post-STC prognosis. The patients with a negative PET scan had a better prognosis compared with those with a positive scan in PFS and OS. In the subgroup analysis, F-FDG PET had a higher value in predicting prognosis before SCT for HL patients.

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.

Current role of FDG PET/CT in lymphoma

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

Predictive value of [¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography for clinical outcome in patients with relapsed/refractory diffuse large B-cell lymphoma prior to and after autologous stem cell transplant

We evaluated the predictive value of [(18)F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) for clinical outcome such as progression-free survival (PFS) and overall survival (OS) in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) prior to and after autologous stem cell transplant (ASCT). FDG-PET/computed tomography (CT) was performed in 39 consecutive patients with relapsed/refractory DLBCL scheduled for ASCT. The median follow-up of surviving patients was 3 years (range 19-66 months). Both pre- and post-ASCT, FDG-PET findings were strongly correlated with PFS and OS (p < 0.005). The 2-year PFS estimates for FDG-negative versus -positive patients were 84.8% vs. 36.8% (pre-) and 81.1% vs. 13.3% (post-). The 2-year OS estimates in these groups were 95.5% vs. 68.3% (pre-) and 92.7% vs. 57.1% (post-). Patients were classified into three groups according to FDG-PET results before and after ASCT. The median PFS was significantly lower in the +/+ group (13.0 months) as compared with the +/- group (31.0 months, p = 0.021) and the -/- group (p = 0.000). The regression model showed that the predictive value of FDG-PET before ASCT owed its significance to a very high hazard ratio between patients with positive and negative imaging (p < 0.01). FDG-PET prior to and following ASCT in patients with relapsed or refractory DLBCL contains prognostic information on long-term clinical outcome.

Tumor associated macrophages in relapsed and refractory Hodgkin lymphoma

BACKGROUND

Growing evidence demonstrates that an increased number of CD68 positive tumor-associated macrophages (TAM) is associated with decreased survival in patients with newly diagnosed classic Hodgkin lymphoma (HL). However, the impact of TAM in relapsed and refractory disease is unknown.

DESIGN AND METHODS

To investigate whether the presence of elevated CD68 retains its prognostic significance in the relapsed and refractory setting, we analyzed pre-salvage biopsy specimens of 81 patients with relapsed and refractory HL using a tissue microarray. Scoring of CD68 was based on the percentage of CD68 positive TAM compared to the total number of cells in representative areas. The final percent of CD68 positivity for each case was based on the average of cores available for examination.

RESULTS

In a univariate analysis, we found that patients with elevated levels of CD68 positive TAM had inferior overall survival (OS) compared with patients who had lower CD68 levels. For patients undergoing autologous stem cell transplant after salvage treatment, elevated CD68 levels were predictive of both adverse OS and event free survival. However, after adjusting for other variables, increased CD68 positive TAM did not retain prognostic significance in a multivariate model.

CONCLUSIONS

In our dataset of primary refractory and relapsed Hodgkin lymphoma biopsy specimens, TAM infiltration is unable to definitively predict outcome. In order to validate these findings, TAM infiltration of relapsed and refractory specimens should be assessed prospectively and paired to initial Hodgkin lymphoma biopsies at diagnosis.

Role of Functional Imaging in the Management of Lymphoma

18-F-fluorodeoxyglucose (FDG) –positron emission tomography (PET), and more recently PET/computed tomography (CT), is the most sensitive and specific imaging technique currently available for patients with lymphoma. Nevertheless, despite being increasingly used in pretreatment assessment, midtreatment evaluation of response, post-treatment restaging, and surveillance during follow-up of patients with lymphoma, its impact on clinical outcome in most clinical situations remains to be confirmed. PET/CT provides its greatest clinical benefit in the post-treatment evaluation of Hodgkin's lymphoma and diffuse large B-cell lymphoma; however, the role of metabolic imaging in other indications and in other histologies remains to be demonstrated. Ongoing risk-adapted studies will hopefully provide evidence for clinical improvement on the basis of altering treatment as a result of interim PET results. Efforts are ongoing to better standardize the conduct and interpretation of FDG-PET scans. FDG-PET has the potential to improve lymphoma patient management; however, its usefulness will likely vary by histology, stage, therapy, and clinical setting.

PET-CT Imaging of Lymphoma

PET-CT is now the mainstay for imaging lymphoma patients. The complimentary nature of the metabolic and anatomic information provided by a PET-CT examination has become an essential component of patient management, complimenting clinical and laboratory criteria used in staging, restaging, and therapy monitoring. The nature of a particular lymphoma subtype and the patient’s clinical presentation will determine the extent PET-CT imaging is best employed in a particular patient’s management.

Early post transplant (F-18) 2-fluoro-2-deoxyglucose positron emission tomography does not predict outcome for patients undergoing auto-SCT in non-Hodgkin and Hodgkin lymphoma

Positron emission tomography (PET) in conjunction with computed tomography is a frequently used modality for staging patients with lymphoma. Utility of PET-computed tomography before or early following auto-SCT has not been as rigorously evaluated. We retrospectively analyzed patients who received auto-SCT for treatment of relapsed or refractory non-Hodgkins lymphoma or Hodgkins disease between the years of 1996 and 2007. Patients who had either a PET scan following salvage chemotherapy within 14 weeks of transplantation (pre-PET), and/or a PET scan 6-14 weeks following transplantation (post-PET) were included. A total of 90 patients were identified for analysis. The median follow-up time is 3.3 years, with a range of 0.13-12.0 years. The median PFS was 4.6 years, and median OS was 5.1 years. At the time of this analysis, 34 patients (37%) experienced disease relapse, and 25 (27%) of the patients died from disease progression. In multivariate Cox proportional hazards analysis, post-PET did not predict for outcome, pre-PET positivity predicted for decrease in PFS. In conclusion, post-PET scan did not predict for PFS or OS in multivariate analysis. Positive pre-PET scan did predict for PFS as seen in previous studies, and may help identify patients who would benefit from innovative post transplant therapies.

Stem cell transplantation in brain tumors: a new field for molecular imaging?

Neural stem cells have been proposed as a new and promising treatment modality in various pathologies of the central nervous system, including malignant brain tumors. However, the underlying mechanism by which neural stem cells target tumor areas remains elusive. Monitoring of these cells is currently done by use of various modes of molecular imaging, such as optical imaging, magnetic resonance imaging and positron emission tomography, which is a novel technology for visualizing metabolism and signal transduction to gene expression. In this new context, the microenvironment of (malignant) brain tumors and the blood-brain barrier gains increased interest. The authors of this review give a unique overview of the current molecular-imaging techniques used in different therapeutic experimental brain tumor models in relation to neural stem cells. Such methods for molecular imaging of gene-engineered neural stem/progenitor cells are currently used to trace the location and temporal level of expression of therapeutic and endogenous genes in malignant brain tumors, closing the gap between in vitro and in vivo integrative biology of disease in neural stem cell transplantation.

Fluorine-18-fluorodeoxyglucose positron emission tomography in response assessment before high-dose chemotherapy for lymphoma: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis to better define the prognostic ability of fluorine-18-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) following salvage chemotherapy for relapsed or refractory Hodgkin's lymphoma (HL) and aggressive non-Hodgkin's lymphoma.

METHODS

We searched PubMed (from inception to January 31, 2010), bibliographies, and review articles without language restriction. Two assessors independently assessed study characteristics, quality, and results. We performed a meta-analysis to determine prognostic accuracy.

RESULTS

Twelve studies including 630 patients were eligible. The most commonly evaluated histologies were diffuse large B-cell lymphoma (n = 313) and HL (n = 187), which were typically treated with various salvage and high-dose chemotherapy regimens. Studies typically employed nonstandardized protocols and diagnostic criteria. The prognostic accuracy was heterogeneous across the included studies. (18)F-FDG PET had a summary sensitivity of 0.69 (95% confidence interval [CI], 0.56-0.81) and specificity of 0.81 (95% CI, 0.73-0.87). The summary estimates were stable in sensitivity analyses. In four studies that performed direct comparisons between PET and conventional restaging modalities, PET had a superior accuracy for predicting treatment outcomes. Subgroup and metaregression analyses did not identify any particular factor to explain the observed heterogeneity.

CONCLUSION

(18)F-FDG PET performed after salvage therapy appears to be an appropriate test to predict treatment failure in patients with refractory or relapsed lymphoma who receive high-dose chemotherapy. Some evidence suggests PET is superior to conventional restaging for this purpose. Given the methodological limitations in the primary studies, prospective studies with standardized methodologies are needed to confirm and refine these promising results.

Predictive value of (18)F-FDG hybrid PET/CT for the clinical outcome in patients with non-Hodgkin's lymphoma prior to and after autologous stem cell transplantation

OBJECTIVE

Evaluation of therapeutic response in non-Hodgkin's lymphoma (NHL) patients with autologous stem cell transplantation (ASCT) is of great clinical significance. But the exact role of (18)F-fluorodeoxyglucose (FDG) imaging in NHL associated with ASCT is unclear. This study assessed the predictive value of (18)F-FDG hybrid PET/CT imaging for the clinical outcome such as progression-free survival (PFS) in patients with NHL prior to and after ASCT.

METHODS

(18)F-FDG hybrid PET/CT was performed in 31 patients (24 male and 7 female) with pathologically confirmed NHL prior to and after ASCT. Mean age was 43.1+/-13.8 years. No patients were lost to follow-up earlier than 1 year from ASCT. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of (18)F-FDG hybrid PET/CT before ASCT were compared to the results after ASCT. The results of pre- and post-ASCT FDG hybrid PET/CT findings were correlated to PFS using Kaplan-Meier survival analysis. Regression analyses were employed to test for independence of established prognostic factors.

RESULTS

Sixteen of 31 patients (52%) progressed/relapsed or died after a median follow-up of 7 months, the remaining 15 patients (48%) were disease free after a median follow-up of 24 months. Both pre- and post-ASCT, (18)F-FDG hybrid PET/CT findings showed high PPV, NPV and accuracy (85.7 versus 92.3%, 76.5 versus 77.8% and 80.6 versus 83.9%). Both pre- and post-ASCT, (18)F-FDG hybrid PET/CT findings were strongly correlated with PFS (P<0.0005, significant). Of pre- ASCT FDG finding, the 1-year PFS rate for FDG-negative and FDG-positive patients was 88.2 and 28.6%. Of post-ASCT FDG finding, the 1-year PFS rate for FDG-negative patients and FDG-positive patients was 88.9 and 23.1%. The regression model showed that the predictive value of FDG imaging owed its significance to the very high hazard ratio between patients with positive FDG imaging and negative FDG imaging (P<0.005) both pre- and post-ASCT.

CONCLUSIONS

(18)F-FDG hybrid PET/CT imaging prior to and following autologous stem cell transplantation in NHL contains predictive information on the long-term clinical outcome.

PET and PET/CT for response evaluation in lymphoma: Current practice and developments

Positron emission tomography (PET) using the radiolabelled glucose analog 2-[18F]fluoro-2-deoxy-d-glucose (FDG) is increasingly used for response assessment in patients with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). These patients often present with a residual mass after therapy, but only a minority will relapse as most of these masses consist of inactive fibrosis. However, some patients have residual disease after first-line treatment and they can benefit from additional or early salvage therapy. Special interest for early, but accurate, assessment of response is growing accordingly. Conventional radiological techniques cannot differentiate between active tumoural tissue and fibrosis in these masses. In contrast, FDG-PET has the ability to differentiate between viable tumour and fibrosis and has been evaluated as an initial staging tool, for response assessment after completion of therapy and as a prognostic marker early during treatment. In this review, we will focus especially on the value of PET for response assessment.

PET imaging in lymphoma

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

Role of 18FDG-PET/CT in detecting relapse during follow-up of patients with Hodgkin's lymphoma

The role of 18FDG-PET/CT during follow-up of patients affected by Hodgkin's lymphoma (HL) in complete remission after treatment is not fully elucidated, since a wide use of 18F fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) in this setting could be limited by a relative high rate of false-positive results. Herein, we summarize a retrospective analysis of 27 patients with Hodgkin's lymphoma in complete remission after the first-line (n = 20) or salvage (n = 7) therapy receiving serial 18FDG-PET/CT scans during follow-up. Out of 165 scans, 13 were suspected for relapse, which was confirmed in seven patients. All relapses were correctly identified by 18FDG-PET/CT positivity, with a 100% sensitivity; false-positive rate was 46% and negative predictive value was 100%. True-positive findings were mostly associated with multiple sites, subdiaphragmatic involvement, and/or previous sites of disease. According to our results, we conclude that performing routine PET/CT scan during follow-up of those patients who are at high risk of relapse would be advisable, although caution must be adopted when interpreting PET/CT results due to the relatively high rate of false-positive findings. If FDG abnormal uptake is present at multiple nodal sites, subdiaphragmatic lymph nodes, or previous sites of disease, histological verification of PET abnormal findings is warranted.

The role of FDG-PET imaging and involved field radiotherapy in relapsed or refractory diffuse large B-cell lymphoma

We examined the role of fluorodeoxyglucose-positron emission tomography (FDG-PET) and the addition of involved field radiotherapy (IFRT) as potential modifiers of salvage therapy. From January 2000 to June 2007, 83 patients with chemosensitive relapsed or primary refractory diffuse large B-cell lymphoma (DLBCL) underwent FDG-PET scans following second-line chemotherapy before high-dose therapy with autologous stem cell rescue (HDT/ASCR). We evaluated the prognostic value of having a negative FDG-PET scan before HDT/ASCR and whether IFRT improved the outcomes. Median follow-up was 45 months, and the 3-year PFS, disease-specific survival (DSS) and OS were 72, 80 and 78%, respectively. Multivariate analysis revealed that a positive FDG-PET scan had worse PFS (hazard ratio=(HR) 3.4; P=0.014), DSS (HR=7.7; P=0.001) and OS (HR=5.4; P=0.001), and that patients not receiving IFRT had worse PFS (HR=2.7; P=0.03) and DSS (HR=2.8, P=0.059). Patients who received IFRT had better local control with fewer relapses within prior involved sites compared with those that did not receive IFRT (P=0.006). These outcomes confirm the important prognostic value of FDG-PET scans before undergoing HDT/ASCR. It also suggests that the role of IFRT should be evaluated further.

Pretransplantation positron emission tomography scan is the main predictor of autologous stem cell transplantation outcome in aggressive B-cell non-Hodgkin lymphoma

BACKGROUND

Limited data exist about the role of second-line chemotherapy response assessed by positron emission tomography (PET) as a prognostic factor in patients with aggressive non-Hodgkin Lymphoma (NHL) who undergo autologous stem cell transplantation (ASCT). The objective of this analysis was to investigate the main determinants of prognosis in patients with aggressive B-cell NHL who undergo ASCT, focusing on the impact of pretransplantation PET, secondary age-adjusted International Prognostic Index (sAA-IPI) score, histology, and previous response to first-line chemotherapy.

METHODS

Seventy-five patients with diffuse, large B-cell lymphoma or grade 3 follicular lymphoma who were treated at the author' institution with second-line chemotherapy (combined ifosfamide, etoposide, and epirubicin [IEV]) followed by ASCT between September 2002 and September 2006 were included. All patients were evaluated by PET after 1 to 3 courses of IEV chemotherapy before ASCT, and all patients received a conditioning regimen of combined carmustine, etoposide, cytosine arabinoside, and melphalan. The prognostic impact of pretransplantation PET, sAA-IPI score, histology, and previous response to first-line chemotherapy was evaluated by univariate and multivariate analyses.

RESULTS

Seventy-two of 75 patients underwent ASCT. In a univariate analysis for progression-free survival (PFS) and overall survival (OS), a significant association was observed with pretransplantation PET (PFS, P< .00001; OS, P< .01) and previous first-line response (PFS, P= .02; OS, P= .04). In the multivariate framework, pretransplantation PET was identified as the only independent prognostic factor (PFS, P< .001; OS, P= .01).

CONCLUSIONS

The current data indicated that pretransplantation PET is the main prognostic predictor in patients with aggressive B-cell NHL who are scheduled for ASCT.

FDG-PET scans in patients with lymphoma

Lymphoma comprises a complex set of diseases, including Hodgkin and non-Hodgkin subtypes. An expected goal of management is chronic disease control over decades in most patients with indolent subtypes, and cure is a realistic target for aggressive histologies, including Hodgkin lymphoma. Making methods available to better assess prognosis and to more specifically tailor therapy toward individual subtypes is a priority. Positron emission tomography using the tracer (18)fluoro-2-deoxyglucose (FDG-PET) has become a valuable tool in the care of patients with lymphoma; it contributes information on staging and response assessment that has the potential to affect and improve patient care. This imaging modality is also being explored as an early response assessor, potentially allowing early prediction of an individual's response to a specific therapy. This information ultimately may lead to modifications of treatment to improve efficacy or reduce toxicity. Although FDG-PET offers valuable information, it is important to recognize its limitations as well as areas that require further exploration in order to optimally integrate its use into the clinical management of lymphoma patients.

Disease staging with positron emission tomography or gallium scanning and use of rituximab predict outcome for patients with diffuse large B-cell lymphoma treated with autologous stem cell transplantation

Tumor status, as determined by positron emission tomography or gallium scanning (PET/G), may be an important predictor of outcome for patients with diffuse large B-cell lymphoma (DLBCL) undergoing autologous stem cell transplantation (ASCT). ASCT conditioning regimens that include rituximab may reduce the rate of relapse. We evaluated the influence of rituximab on overall and progression-free survival in patients with DLBCL based on PET/G status before ASCT. A retrospective review of all patients with chemosensitive DLBCL who underwent ASCT in the context of research protocols at our institution between 1995 and 2005 was performed. Our study included 174 patients. Disease status before ASCT, according to PET/G, was negative in 136 patients (78%), positive in 29 patients (17%), and unknown in nine patients (5%). PET/G status and rituximab use were the only factors predictive of progression-free survival in multivariate analyses: the hazard ratios for relapse were 2.9 for PET/G-positive versus -negative patients (P < 0.001) and 0.4 for rituximab versus no rituximab use (P = 0.001). We conclude that evidence of disease on PET/G scanning prior to transplantation is associated with an increased risk for relapse after ASCT. Transplantation regimens containing rituximab can reduce this risk, regardless of PET/G status.

Prognostic impact of pre-transplantation computed tomography and 67gallium scanning in chemosensitive diffuse large B cell lymphoma patients undergoing hematopoietic stem-cell transplantation

OBJECTIVE

In the present study, we evaluated computed tomography (CT) and (67)gallium scanning ((67)Ga scan) pre-transplant as prognostic factors for overall survival (OS) and event-free survival (EFS) in patients with diffuse large B cell lymphoma, undergoing high-dose chemotherapy and stem-cell transplantation.

PATIENTS AND METHODS

Forty-two patients were included. Of these, 9 (21%) had both positive CT and (67)Ga scans, 17 (41%) negative results with both techniques, and 16 (38%) positive CT/negative (67)Ga scan. Whole-body planar imaging and single-photon emission computed tomography (SPECT) were performed 72 h after an intravenous administration of (67)Ga citrate measuring between 7 mCi and 10 mCi (259-370 MBq).

RESULTS

Patients with positive CT/positive (67)Ga scan had a significantly worse EFS and OS at 5 years than those with negative (67)Ga scan regardless of whether it was associated with a positive or a negative CT scan (29% and 16% vs. 81% and 93% vs. 88% and 100%, respectively, P < 0.001). After a median follow-up of 43 months (range 4-130 months), no differences were observed between patients with negative CT/negative (67)Ga scan and those with positive CT/negative (67)Ga scan, with an EFS and OS at 5 years of 88% versus 81% and 100% versus 93%, respectively. In multivariate analysis, the presence of a pre-transplant positive CT/(67)Ga scans adversely influenced both EFS and OS [HR 8, 95% confidence interval (CI) (1.4-38), P = 0.03 and HR 2; 95% CI (1.3-8), P = 0.02, respectively].

CONCLUSIONS

(67)Ga scan helps to identify, in the pre-transplant evaluation, two groups with a different outcome: one group of patients with positive CT and negative (67)Ga scans pre-transplant, who showed a favorable outcome with a low rate of relapse, and the other group of patients with both positive CT and (67)Ga scans pre-transplant, who showed a poor prognosis and did not benefit from autologous stem-cell transplantation. They should have been offered other therapeutic strategies.

Conventional allogeneic hematopoietic stem cell transplantation for lymphoma may overcome the poor prognosis associated with a positive FDG-PET scan before transplantation

A positive scan in pretransplantation fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) has been shown to be associated with a poor prognosis in patients with lymphoma undergoing high-dose chemotherapy followed by autologous stem cell transplantation (ASCT). For those with a positive FDG-PET scan, treatment that includes allogeneic stem cell transplantation (allo-SCT) may be an alternative. However, it is uncertain whether allo-SCT can overcome a poor prognosis. Therefore, we conducted a retrospective analysis of 14 patients with lymphoma who had undergone FDG-PET scan within one month before allo-SCT at our institution. Eleven patients were FDG-PET-positive and three were negative. With a median follow-up of 17 months (range: 6-44) after allo-SCT, the cumulative incidence of progression was 29.3% in FDG-PET-positive patients and 0% in the FDG-PET-negative patients. Four of the 11 patients who had post-transplantation FDG-PET showed FDG-avid lesions on the first post-transplantation scan. In two of the four, regression of the lesions was observed during the scheduled reduction of immunosuppressant without donor lymphocyte infusion and remained without progression at the last follow-up (34 and 8 months). Durable responses after allo-SCT, at least with conventional conditioning regimens, can be expected in patients with FDG-PET-positive lesions before transplantation. Thus, conventional allo-SCT could be an attractive modality compared to ASCT for patients with positive FDG-PET after the completion of conventional salvage chemotherapy, and particularly for patients with T and NK-cell lymphomas.

FDG PET and risk-adapted therapy in Hodgkin's and non-Hodgkin's lymphoma

PURPOSE OF REVIEW

The prognostic utility of midtreatment fluorine-18 fluorodeoxyglucose positron emission tomography (F-FDG PET) has become widely appreciated in aggressive B-cell non-Hodgkin's lymphoma and, more recently, in Hodgkin's lymphoma. Outcomes based on midtreatment FDG PET performed during primary and salvage therapy are reviewed and management strategies considered, with a focus on treatment intensification for poor-risk disease as identified by metabolic imaging.

RECENT FINDINGS

PET, when performed after as few as two cycles of primary chemotherapy, is strongly prognostic in certain aggressive lymphomas and provides information independently from validated prognostic indices. What constitutes a positive or negative scan is not always clear, particularly if there is minimal tracer uptake, and the causes of false positive and false negative scans must be considered. How to tailor therapy based on the midtreatment PET result is the focus of current trials and is presently being defined for both Hodgkin's and non-Hodgkin's lymphoma.

SUMMARY

Early PET has the strong potential to improve clinical outcomes by sparing good-risk patients from overly aggressive treatments, and by more accurately identifying poor-risk patients so as to guide changes in management. Treatment modifications on the basis of midtreatment PET are presently best made in clinical trial settings.

Non-Hodgkin lymphoma: retrospective study on the cost-effectiveness of early treatment response assessment by FDG-PET

PURPOSE

Although lymphomas are very chemosensitive, 50% of patients with aggressive non-Hodgkin lymphoma (NHL) are not cured with standard first-line treatment. This consists of six cycles of doxorubicin, vincristine, prednisolone and cyclophosphamide (CHOP), recently complemented with rituximab. Preliminary studies show that PET mid-treatment is a good predictor of the remission status at the end of therapy. As patients with persistent FDG uptake after three cycles are unlikely to gain a complete remission, the remaining three cycles of chemotherapy are useless. We investigated the costs and benefits for the use of PET in this early treatment setting.

METHODS

We conceived a model using a conventional arm where patients receive the full regimen of six cycles of CHOP [-rituximab] and an experimental algorithm where patients receive either six cycles (PET response) or only three cycles (PET non-response). Based on a patient sample (2004-2006), we calculated the costs for hospitalisation and treatment. We took into account all costs accrued (including overhead costs). We used a sensitivity analysis by varying the most important parameters.

RESULTS

With a PET price of 700 euro and CHOP price (per cycle) of 1,829 euro , we can conclude to cost saving of 1,879 euro per patient. The PET price can increase up to 2,580 euro and the cost for one cycle of CHOP can decrease to 500 euro per cycle before cost savings are nil. The percentage of non-responders may be as low as 10%. The implementation of rituximab in first-line therapy only increases benefit (4,900 euro/pt).

CONCLUSION

We conclude to substantial cost savings if management of NHL patients is based on mid-treatment PET scan. The economical data we used seem to be comparable to those published in other European studies. Implementation of Mabthera in first line only increases cost savings.

PET/CT in oncology: for which tumours is it the reference standard?

Positron emission tomography (PET)/computed tomography (CT) has a growing role in the imaging of many cancers. As our experience has grown over the past number of years so has our understanding for which cancers it is particularly useful. The value of PET/CT at each stage of the cancer journey is different for each cancer. This review attempts to tease out the role of PET/CT in the common cancers with particular emphasis on where it is the imaging investigation of choice.

Is [18F]fluorodeoxyglucose Positron Emission Tomography the Ultimate Tool for Response and Prognosis Assessment?

[(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) is currently the most accurate and reliable tool for the assessment of response in Hodgkin's lymphoma (HL). FDG-PET is superior to conventional imaging techniques for detection of residual disease at the end of treatment, especially in the presence of a residual mass, a frequent finding in HL. FDG-PET response assessment has also a high predictive value early after the initiation of therapy. However, whether risk-adapted treatment strategies based on FDG-PET may also improve patient outcome remains to be proved.

The role of FDG-PET scans in patients with lymphoma

18-Fluoro-deoxyglucose positron emission tomography (FDG-PET) is a noninvasive, 3-dimensional imaging modality that has become widely used in the management of patients with malignant lymphomas. This technology has been demonstrated to be more sensitive and specific than either (67)gallium scintigraphy or computerized tomography, providing a more accurate distinction between scar or fibrosis and active tumor. PET scans have been evaluated in pretreatment staging, restaging, monitoring during therapy, posttherapy surveillance, assessment of transformation, and, more recently, as a surrogate marker in new drug development. Data to support these various roles require prospective validation. Moreover, caution must be exercised in the interpretation of PET scans because of technical limitations, variability of FDG avidity among the different lymphoma histologic subtypes, and in the large number of etiologies of false-negative and false-positive results. Recent attempts to standardize PET in clinical trials and incorporation of this technology into uniformly adopted response criteria will hopefully lead to improved outcome for patients with lymphoma.

Pretransplant positive positron emission tomography/gallium scans predict poor outcome in patients with recurrent/refractory Hodgkin lymphoma

BACKGROUND

The objective was to determine the prognostic value of functional imaging (FI) in predicting outcome of patients with recurrent/refractory Hodgkin lymphoma (HL) before undergoing high-dose chemotherapy with autologous stem cell transplantation (ASCT).

METHODS

Clinical and imaging data were retrospectively reviewed in 211 consecutive patients treated with ASCT from February 1993 to May 2004. The FI results were correlated with progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier survival analysis.

RESULTS

Responses were assessed by conventional criteria and evaluated by positron emission tomography (PET) (n = 68) and gallium scans (n = 144) before ASCT. A complete response (CR) or unconfirmed CR (CRu) was seen in 51% of patients, a partial response (PR) in 41% of patients, and stable or progressive disease in 7% of patients. FI was positive in only 6 of 110 (5%) of CR/CRu patients, in 48 of 86 (56%) of PR patients, and in all 3 patients with progressive disease. The 3-year PFS was 69% for patients with negative FI versus 23% for patients with positive FI (P < .0001). The 3-year OS rates were 87% and 58%, respectively (P < .0001). The 3-year PFS for patients in PR with negative FI was 51% comparable to patients in CR (76%) versus 27% for patients in PR with positive FI (P < .0001). In a multivariate model, positive FI was found to be independently prognostic of PFS.

CONCLUSIONS

Pretransplant FI status predicts outcome in patients with recurrent/refractory HL. Positive FI confers a poor prognosis, independent of other traditional presalvage prognostic factors.

The role of FDG PET in the management of lymphoma: what is the evidence base?

[18F]Fluorodeoxyglucose positron emission tomography (18F-FDG PET) is playing an increasing role in the management of both Hodgkin and non-Hodgkin lymphoma, offering potential advantages in the accuracy of disease assessment at a number of points in the management pathway. This review evaluates the current level of confidence in the use of PET technology in (1) initial staging, (2) the assessment of early response to chemotherapy, (3) the assessment of residual masses at completion of initial treatment, (4) follow-up, and (5) radiotherapy planning.

Use of FDG-PET to monitor response to chemotherapy and radiotherapy in patients with lymphomas

Lymphoma is a heterogeneous group of diseases with many curable subtypes. Primary treatment cures a significant proportion of, but not all, patients. Patients not achieving a complete remission with primary treatment, or those who relapse later, have a second chance of cure with high-dose chemotherapy and haematopoietic stem cell transplantation. Response assessment is therefore crucial in the management of lymphomas. FDG-PET has an emerging role in assessing response, both at the end of and during treatment. This article will review the current published evidence and offer some suggestions on future directions from a clinician's viewpoint.

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

PURPOSE

To develop guidelines for performing and interpreting positron emission tomography (PET) imaging for treatment assessment in patients with lymphoma both in clinical practice and in clinical trials.

METHODS

An International Harmonization Project (IHP) was convened to discuss standardization of clinical trial parameters in lymphoma. An imaging subcommittee developed consensus recommendations based on published PET literature and the collective expertise of its members in the use of PET in lymphoma. Only recommendations subsequently endorsed by all IHP subcommittees were adopted.

RECOMMENDATIONS

PET after completion of therapy should be performed at least 3 weeks, and preferably at 6 to 8 weeks, after chemotherapy or chemoimmunotherapy, and 8 to 12 weeks after radiation or chemoradiotherapy. Visual assessment alone is adequate for interpreting PET findings as positive or negative when assessing response after completion of therapy. Mediastinal blood pool activity is recommended as the reference background activity to define PET positivity for a residual mass > or = 2 cm in greatest transverse diameter, regardless of its location. A smaller residual mass or a normal sized lymph node (ie, < or = 1 x 1 cm in diameter) should be considered positive if its activity is above that of the surrounding background. Specific criteria for defining PET positivity in the liver, spleen, lung, and bone marrow are also proposed. Use of attenuation-corrected PET is strongly encouraged. Use of PET for treatment monitoring during a course of therapy should only be done in a clinical trial or as part of a prospective registry.

Molecular Imaging of Brain Tumors: A Bridge Between Clinical and Molecular Medicine?

As the research on cellular changes has shed invaluable light on the pathophysiology and biochemistry of brain tumors, clinical and experimental use of molecular imaging methods is expanding and allows quantitative assessment. The term molecular imaging is defined as the in vivo characterization and measurement of biologic processes at the cellular and molecular level. Molecular imaging sets forth to probe the molecular abnormalities that are the basis of disease rather than to visualize the end effects of these molecular alterations and, therefore, provides different additional biochemical or molecular information about primary brain tumors compared to histological methods "classical" neuroradiological diagnostic studies. Common clinical indications for molecular imaging contain primary brain tumor diagnosis and identification of the metabolically most active brain tumor reactions (differentiation of viable tumor tissue from necrosis), prediction of treatment response by measurement of tumor perfusion, or ischemia. The interesting key question remains not only whether the magnitude of biochemical alterations demonstrated by molecular imaging reveals prognostic value with respect to survival, but also whether it identifies early disease and differentiates benign from malignant lesions. Moreover, an early identification of treatment success or failure by molecular imaging could significantly influence patient management by providing more objective decision criteria for evaluation of specific therapeutic strategies. Specially, as molecular imaging represents a novel technology for visualizing metabolism and signal transduction to gene expression, reporter gene assays are used to trace the location and temporal level of expression of therapeutic and endogenous genes. Molecular imaging probes and drugs are being developed to image the function of targets without disturbing them and in mass amounts to modify the target's function as a drug. Molecular imaging helps to close the gap between in vitro and in vivo integrative biology of disease.

PET in lymphoma

This review attempts to discuss the role of positron emission tomography (PET) imaging for staging, treatment response and follow-up of patients with lymphoma. The pitfalls and impact of PET imaging on the clinical management are also addressed.

Interobserver and Intraobserver Variability of Standardized Uptake Value Measurements in Non–small-cell Lung Cancer

OBJECTIVES

To assess interobserver and intraobserver variabilities in measuring the maximal standardized uptake value (SUV) of non-small-cell lung cancer.

METHODS

Positron emission tomography-computed tomography examinations of 20 consecutive patients referred for initial evaluation of newly diagnosed non-small-cell lung cancer were retrospectively reviewed by 5 experienced positron emission tomography-computed tomography readers, who independently measured the maximal SUV/body weight of the primary tumors. Interobserver and intraobserver variabilities were assessed by using 4 statistical methods: correlation, regression analysis, Bland-Altman analysis, and analysis of variance. The SUV measurements derived in the study were compared with the SUV measurements documented in the original reports using correlation and regression analysis. The percentages of tumors whose retrospective SUV measurements were more than 20% different and more than 25% different from those in the original report were assessed.

RESULTS

Both interobserver and intraobserver SUV measurements were highly reproducible. Pearson correlation coefficients were greater than 0.95 and 0.94, respectively. Good interobserver and intraobserver agreement was shown with regression analysis (F test P value >0.05), the Bland-Altman analysis, and analysis of variance (F test P value >0.95). The mean original SUV was much less than the mean study SUV (P<0.05). The study SUV differed from the SUV of the original report by more than 20% in 50% of the tumors, and by more than 25% in 45% of the tumors.

CONCLUSIONS

There was excellent interobserver and intraobserver agreement in SUVs measured in the study environment but poor agreement between study SUVs and those documented in original reports, which can affect treatment decisions substantially.

How useful is PET/CT imaging in the management of post-transplant lymphoproliferative disease after liver transplantation?

Post-transplant lymphoproliferative disease (PTLD) is a serious and potentially life-threatening complication after solid organ transplantation. Here, we report our first experience with the use of PET/CT (positron emission tomography combined with computed tomogram) for the management of patients with PTLD after liver transplantation. Four patients with histologically proven PTLD were analyzed. Conventional work-up included physical examination and head-to-pelvis CT. PET/CT was used in one patient for initial staging and in all patients for follow-up. PET/CT positive findings underwent biopsy. Information provided by PET/CT resulted in a change of medical management in three of the four patients. Conventional work-up missed residual disease after surgery in one and failed to detect a tumor relapse in another patient. However, one patient disclosed a false positive PET/CT finding in the lungs. In conclusion, PET/CT may be a useful tool for staging and therapy monitoring of PTLD after liver transplantation.