Prognostic role of PET scanning before and after reduced-intensity allogeneic stem cell transplantation for lymphoma

Fluorodeoxyglucose-Positron Emission Tomography in Relapsed/Refractory Hodgkin Lymphoma: A Practical Approach

BACKGROUND

Positron emission tomography (PET) with the use of 18F-fluorodeoxyglucose (FDG), implemented with low-dosage computer tomography, is to be considered as the most important evolution of imaging in the management and assessment of classical Hodgkin lymphoma patients.

SUMMARY

According to Lugano response criteria, FDG-PET is mandatory to define metabolic response to frontline therapy and moreover it is important in the definition of nonresponders or refractory disease patients. Refractory disease is reported in about 15% of patients, with some variations based on the choice of first-line chemotherapy, and particularly in advanced stages, up to 40% eventually relapse within 3 years.

KEY MESSAGES

The aim of this review was to highlight a practical way to use FDG-PET in the subset of HL, with some notes of its use in first-line patients, and particularly centered on relapsed or refractory setting with a final focus of the evaluation of response by FDG-PET in the new treatment era of immunocheckpoint inhibitors.

Prognostic value of pre-transplantation total metabolic tumor volume on 18fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography in relapsed and refractory aggressive lymphoma

Relapsed and refractory aggressive lymphoma have a poor prognosis. High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) is effective in chemosensitive patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is among the few options for non-chemosensitive patients. ¹⁸Fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (¹⁸FDG-PET/CT) is the standard tool for evaluating response to chemotherapy and residual tumor volume. However, accurate assessment of residual tumor volume is not currently being achieved in clinical practice, and its value in prognostic and therapeutic stratification remains unclear. To answer this question, we investigated the efficacy of quantitative indicators, including total metabolic tumor volume (TMTV), in predicting prognosis after auto-HSCT and allo-HSCT. We retrospectively analyzed 39 patients who received auto-HSCT and 28 who received allo-HSCT. In the auto-HSCT group, patients with a higher TMTV had a poor prognosis due to greater risk of relapse. In the allo-HSCT group, patients with a higher TMTV had a lower progression-free survival rate and a significantly higher relapse rate. Neither Deauville score nor other clinical parameters were associated with prognosis in either group. Therefore, pre-transplant TMTV on PET is effective for prognostic prediction and therapeutic decision-making for relapsed or refractory aggressive lymphoma.

Post-transplantation Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography in Patients with Lymphoblastic Lymphoma is an Independent Prognostic Factor with an Impact on Progression-Free Survival but not Overall Survival

Purpose: In the present study, we mainly aimed to evaluate the prognostic value of 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) positron emission tomography (PET)/computed tomography (CT) after allogeneic stem cell transplantation (allo-SCT) in lymphoblastic lymphoma (LBL) patients using Deauville Scores (DS). Materials and Methods: A total of 63 LBL patients who benefited from ¹⁸F-FDG PET-CT after allo-SCT in our institution between April 2010 and August 2020 were enrolled in this retrospective study. These above-mentioned patients were divided into two groups based on the Deauville criteria. Diagnostic efficiency of ¹⁸F-FDG PET/CT and integrated CT in detecting lymphoma were calculated. Consistencies were evaluated by comparing 18F-FDG PET/CT and integrated CT results through kappa coefficient. Kaplan-Meier method was used in survival analysis, and the log-rank method was adopted in comparisons. Prognostic factor analysis was performed by the Cox regression model. Results: The sensitivity, specificity, positive predictive value, negative predictive value, accuracy of post-SCT ¹⁸F-FDG PET-CT were 100%(12/12), 92.2%(47/51), 75.0%(12/16), 100%(47/47) and 93.7%(59/63). The consistency of 18F-FDG PET-CT and integrated CT was moderate(Kappa = .702，P < .001). Positive post-SCT 18F-FDG PET-CT was associated with lower progression-free survival (PFS) but not overall survival (OS) (p = .000 and p = .056, respectively). The 3-year PFS of the PET-positive group and PET-negative group was 18.8% and 70.2%, respectively. Multivariate analysis showed that post-SCT PET-CT findings was an independent prognostic factor for PFS (p = .000; HR, 3.957; 95%CI, 1.839-8.514). Other factors independently affecting PFS were sex (p = .018; HR, 2.588; 95% CI, 1.181 − 5.670) and lactate dehydrogenase (LDH) (p = .005; HR, 3.246; 95% CI, 1.419 − 7.426). However, none of the above-mentioned factors were associated with OS. Conclusions: Collectively, we found that 18F-FDG PET-CT after allo-SCT was a strong indicator for PFS, but not OS, which might provide important evidence for the selection of subsequent treatment regimen for LBL patients. Trial registration number: ChiCTR2100046709.

Cellular Immunotherapy for Refractory Diffuse Large B Cell Lymphoma in the Chimeric Antigen Receptor-Engineered T Cell Era: Still a Role for Allogeneic Transplantation?

Chimeric antigen receptor-engineered T (CART) cells are a promising new treatment option for patients with multiply relapsed and refractory (R/R) diffuse large B cell lymphoma (DLBCL). Because of the favorable outcome data reported for CART cells, uncertainty is emerging if there is still a role for allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of R/R DLBCL. This article provides an overview of available evidence and theoretical considerations to put these 2 types of cellular immunotherapy (CI) into perspective. Altogether, current data suggest that CART cells are preferred now over transplantation as first-choice CI in many clinical situations. However, the majority of patients will fail CART therapy, resulting in an unmet medical need where allo-HCT could be beneficial. In contrast, employing allo-HCT instead of CART cells as first CI should be presently restricted to situations where CART cell therapy is deemed not feasible or useful, such as patients with refractory cytopenia or incipient myelodysplastic syndrome. However, allo-HCT remains a standard treatment option as first CI for patients with chemosensitive R/R DLBCL when CARTs are not available or transplantation is preferred by the patient. Continuous collection and analysis of CI outcome data by professional registries appear to be of key importance for developing rational strategies of CI allocation and sequencing.

Prognostic Value of Pre-Autologous Stem Cell Transplantation PET/CT in Diffuse Large B-Cell Lymphoma: The Deauville Score Is Prognostically Superior to ΔSUVmax

OBJECTIVE

The predictive value of pre-autologous stem cell transplantation (pre-ASCT) positron emission tomography/computed tomography (PET/CT) scans according to different criteria remains elusive in patients with diffuse large B-cell lymphoma (DLBCL).

METHODS

A total of 46 DLBCL patients treated with pre-ASCT were enrolled in the present study, and two methods, Deauville score and maximal standardized uptake value reduction (ΔSUVmax), were used to evaluate the PET/CT scans before transplantation.

RESULTS

In patients with Deauville 1-3 and ≥4, the 2-year progression-free survival (PFS) rates were 82.8 and 11.8% (p < 0.001), respectively, while the 2-year overall survival (OS) rates were 89.7 and 41.2%, respectively (p < 0.001). When using the ΔSUVmax cut-off of 66% criterion, in patients with a ΔSUVmax of >66 and ≤66%, the 2-year PFS rates were 78.1 and 7.1%, respectively (p < 0.001), while the 2-year OS rates were 87.5 and 35.7%, respectively (p < 0.001). In the univariate analysis, the ΔSUVmax, Deauville score, NCCN-IPI and serum lactate dehydrogenase levels were significantly correlated with the 2-year PFS/OS. Furthermore, the multivariate analysis revealed that the Deauville score was an independent prognostic factor for 2-year PFS.

CONCLUSION

The present results indicate that PET/CT scans at pre-ASCT can predict the survival of DLBCL patients, and the Deauville score is better than ΔSUVmax in prognostic prediction.

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.

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.

[Preventative and therapeutic relapse strategies after allogeneic hematopoietic stem cell transplantation: Guidelines from the Francophone society of bone marrow transplantation and cellular therapy (SFGM-TC)]

Disease relapse remains the first cause of mortality of hematological malignancies after allogeneic hematopoietic stem cell transplantation (allo-HCT). The risk of recurrence is elevated in patients with high-risk cytogenetic or molecular abnormalities, as well as when allo-HCT is performed in patients with refractory disease or with persistent molecular or radiological (PET-CT scan) residual disease. Within the frame of the 7th annual workshops of the francophone society for bone marrow transplantation and cellular therapy, the working group reviewed the literature in order to elaborate unified guidelines for the prevention and treatment of relapse after allo-HCT. For high risk AML and MDS, a post transplant maintenance strategy is possible, using hypomethylating agents or TKI anti-FLT3 when the target is present. For Philadelphia positive ALL, there was a consensus for the use of post-transplant TKI maintenance. For lymphomas, there are no strong data on the use of post-transplant maintenance, and hence a preemptive strategy is recommended based on modulation of immunosuppression, close follow-up of donor chimerism, and donor lymphocytes infusion. For multiple myeloma, even though the indication of allo-HCT is controversial, our recommendation is post transplant maintenance using bortezomib, due to its a good toxicity profile without increasing the risk of GVHD.

18F-FDG PET/CT in the clinical management of patients with lymphoma

The aim of this work was to review the current recommendations for staging and response assessment of patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) in routine clinical practice after chemotherapy and/or stem cell transplantation. A five-point scale (5-PS) from the First International Workshop on PET in Lymphoma in Deauville, France, in 2009, was recommended as the standard tool to score imaging to assess treatment response in patients with lymphoma using ¹⁸F-Fluorodeoxyglucose (FDG) PET/CT. Following the recommendations of the 11th and 12th International Conferences on Malignant Lymphoma held in Lugano (Switzerland), in 2011 and 2013, respectively, a consensus (the so-called Lugano Classification) was reached regarding the use of PET/CT for staging and response assessment in FDG-avid lymphomas. As a result, ¹⁸F-FDG PET/CT was formally incorporated into standard staging for FDG-avid lymphomas. A bone marrow biopsy is no longer indicated for the routine staging of HL and most diffuse large B-cell lymphomas. PET/CT will be used to assess response in FDG-avid histologies using the 5-point scale. The recent introduction of biological agents with immune mechanisms requires flexibility in interpretations of the Lugano criteria due to tumour flare or a pseudo-progression effect produced by these agents. Provisional criteria have been proposed (Lymphoma Response to Immunomodulatory Therapy Criteria) with the introduction of the term 'Indeterminate Response' in order to identify this phenomenon until confirmed as flare/pseudoprogression or true progression. All these recommendations will improve evaluations of patients with lymphoma, and allow comparison of results from clinical practice and trials.

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.

Impact of Pretransplantation (18)F-Fluorodeoxyglucose-Positron Emission Tomography on Survival Outcomes after T Cell-Depleted Allogeneic Transplantation for Hodgkin Lymphoma

Pretransplant (18)F-fluorodeoxyglucose (FDG) positron emission tomography status is an important prognostic factor for outcomes after autologous stem cell transplantation (SCT) in Hodgkin lymphoma (HL), but its impact on outcomes after allogeneic SCT remains unclear. We retrospectively evaluated outcomes after T cell-depleted allogeneic SCT of 116 patients with nonprogressive HL according to pretransplant Deauville scores. Endpoints were overall survival (OS), progression-free survival (PFS), relapse rate (RR), and nonrelapse-related mortality (NRM). OS, PFS, and RR did not differ significantly between the Deauville 1 to 2 and Deauville 3 to 5 cohorts (OS: 77.5% versus 67.3%, P = .49; PFS: 59.4% versus 55.7%, P = .43; RR: 20.9% versus 22.6%, P = .28 at 4 years). Differences in PFS remained statistically nonsignificant when comparisons were made between Deauville 1 to 3 and Deauville 4 to 5 cohorts (60.9% versus 51.4%, P = .10), and RR remained very similar (21.5% versus 23.8%, P = .42). Multivariate analyses demonstrated trends toward significance for an effect of Deauville score on PFS (hazard ratio 1.82 for Deauville 4 to 5, P = .06) and for number of lines of prior therapy on OS (hazard ratio 2.34 for >5 lines, P = .10). The latter effect appeared to be driven by higher NRM rather than increased RR. Our findings suggest that Deauville score before allogeneic SCT in patients with nonprogressive HL has a relatively modest impact on survival outcomes in comparison with the impact in autologous SCT and that predictive values for the individual patient remain low, indicating that residual FDG-avid disease should not preclude allogeneic SCT. Furthermore, our findings bring into question the importance of attainment of metabolic complete response in this setting if it is at the expense of increasing NRM risk.

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.

Value of surveillance studies for patients with stage I to II diffuse large B-cell lymphoma in the rituximab era

BACKGROUND

The role of surveillance studies in limited-stage diffuse large B-cell lymphoma (DLBCL) in the rituximab era has not been well defined. We sought to evaluate the use of imaging (computed tomography [CT] and positron emission tomography [PET]-CT) scans and lactate dehydrogenase (LDH) in surveillance of patients with stage I to II DLBCL.

METHODS

A retrospective analysis was performed of patients who received definitive treatment between 2000 and 2013.

RESULTS

One hundred sixty-two consecutive patients with stage I to II DLBCL were treated with chemotherapy +/- rituximab, radiation, or combined modality therapy. The 5-year rates of overall survival (OS) and freedom from progression (FFP) were 81.2% and 80.8%, respectively. Of the 162 patients, 124 (77%) were followed up with at least 1 surveillance PET scan beyond end-of-treatment scans; of those, 94 of 124 (76%) achieved a complete metabolic response on PET scan after completion of chemotherapy, and this was associated with superior FFP (P=.01, HR=0.3) and OS (P=.01, HR 0.3). Eighteen patients experienced relapse after initial response to therapy. Nine relapses were initially suspected by surveillance imaging studies (8 PET, 1 CT), and 9 were suspected clinically (5 by patient-reported symptoms and 4 by symptoms and physical examination). No relapses were detected by surveillance LDH. The median duration from initiation of treatment to relapse was 14.3 months among patients with relapses suspected by imaging, and 59.8 months among patients with relapses suspected clinically (P=.077). There was no significant difference in OS from date of first therapy or OS after relapse between patients whose relapse was suspected by imaging versus clinically. Thirteen of 18 patients underwent successful salvage therapy after relapse.

CONCLUSIONS

A complete response on PET scan immediately after initial chemotherapy is associated with superior FFP and OS in stage I to II DLBCL. The use of PET scans as posttreatment surveillance is not associated with a survival advantage. LDH is not a sensitive marker for relapse. Our results argue for limiting the use of posttreatment surveillance in patients with limited-stage DLBCL.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

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

A prospective study of an alemtuzumab containing reduced-intensity allogeneic stem cell transplant program in patients with poor-risk and advanced lymphoid malignancies

Reduced-intensity conditioning (RIC) regimens for allogeneic stem cell transplant (allo-SCT) have used alemtuzumab to abrogate the risk of graft-versus-host disease (GVHD). Thirty-eight patients with advanced lymphoma underwent a prospective phase II study of melphalan, fludarabine and alemtuzumab containing RIC allo-SCT from 20 matched related and 18 unrelated donors with cyclosporine-A as GVHD prophylaxis. The cumulative incidence of grade II-IV acute GVHD at 3 months was 10.5% and three evaluable patients experienced chronic GVHD. Progression-free (PFS) and overall (OS) survival at 5 years was 25% (95% confidence interval [CI]: 13-40%) and 44% (95% CI: 28-59%), respectively. Previous high-dose therapy and autologous stem cell transplant (HDT-ASCT) and elevated lactate dehydrogenase (LDH) at the time of allo-SCT resulted in inferior OS. Within this cohort of patients with high-risk lymphoma, alemtuzumab containing RIC resulted in a low risk of GVHD and a high incidence of progression of disease, especially in those with poor-risk features defined by elevated LDH pre-allo-SCT and previous HDT-ASCT.

Pretransplantation fluorine-18-deoxyglucose--positron emission tomography scan lacks prognostic value in chemosensitive B cell non-hodgkin lymphoma patients undergoing nonmyeloablative allogeneic stem cell transplantation

Whether chemosensitivity, as determined by positron emission tomography using fluorine-18-deoxyglucose (FDG-PET), is a requirement for successful allogeneic hematopoietic stem cell transplantation (allo-SCT) has yet to be established. We analyzed 88 patients with B cell non-Hodgkin lymphoma (B-NHL) for event-free (EFS) and overall survival (OS) according to computed tomography (CT) and FDG-PET criteria before uniform nonmyeloablative (NMA) allo-SCT. Patients who were chemosensitive, according to CT criteria, experienced significantly greater EFS (P < .001) and OS (P < .03) compared with those who were chemorefractory at the time of allo-SCT. Of 58 patients within this cohort who were chemosensitive by CT criteria, there was no difference in EFS (P = .85) or OS (P = .96) between FDG-PET-positive (Deauville 4 to 5, n = 24) and FDG-PET-negative (Deauville 1 to 3, n = 34) patients. There was no difference in survival according to age < or ≥ 60 years, prior autologous-stem cell transplantation, allograft characteristics, or histology. FDG-PET adds no prognostic value in chemosensitive B-NHL before NMA-allo-SCT.

Hematopoietic cell transplantation for mantle cell lymphoma: predictive value of pretransplant positron emission tomography/computed tomography and bone marrow evaluations for outcomes

BACKGROUND

The prognostic roles of 18F-fludeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging and marrow involvement evaluation on outcomes following autologous and allogeneic hematopoietic cell transplantation (HCT) for mantle cell lymphoma (MCL) are uncertain and require more data.

PATIENTS AND METHODS

We categorized 66 patients with MCL who received HCT (38 autologous and 28 allogeneic) on the basis of pre-HCT residual disease (RD) status as assessed by marrow MCL morphology and flow/molecular analysis and PET/CT imaging to RD positive (RD(+)) (either or both measures positive) and RD(-) (both negative). We analyzed the predictive value of these RD detection methods on transplant outcomes.

RESULTS

The 2-year relapse rate after autograft was significantly higher in pre-HCT RD(+) patients (46% [95% CI 16-77%]) than in patients who were RD(-) (19% [95% CI 0-42%]; P = .02), leading to worse 5-year disease-free survival (DFS) in RD(+) patients (46% [95% CI 14%-73%] vs. 68% [95% CI 33-87%], P = .04). In multivariate analysis, RD(+) status was associated with a reduction in DFS (hazard ratio, 5.6; P = .02). Most allogeneic HCT recipients had advanced disease and most were RD(+) (12 PET/CT(+); 5 marrow-positive). The 5-year DFS and relapse rates after allogeneic HCT were 34% and 25% for all patients and 40% and 33% for RD(+) recipients, suggesting that active disease at the time of allograft does not preclude long-term remissions in advanced MCL.

CONCLUSION

Both autologous and allogeneic HCT lead to promising long-term survival. RD detected prior to autograft was associated with increased relapse and worse 5 year DFS. Allograft recipients had favorable long-term outcomes even in presence of pre-HCT detectable disease.

When should FDG-PET be used in the modern management of lymphoma?

Positron Emission Tomography (PET) is a functional imaging technique that, combined with computerized tomography (PET-CT), is increasingly used in lymphoma. Most subtypes accumulate fluorodeoxyglucose (FDG) and the increased sensitivity of PET-CT, especially for extranodal disease, compared to CT, makes PET-CT an attractive staging tool. The availability of a staging PET-CT scan also improves the accuracy of subsequent response assessment. 'Interim' PET-CT can be used to assess early response and end-of-treatment PET-CT assesses remission. Clinical trials are currently seeking to establish whether the predictive value of PET-CT can be successfully used to guide individual treatment to reduce toxicity and/or to improve outcomes. Standardized methods for performing and reporting PET have been developed in the context of trials. The role of PET in transplantation selection is currently evolving, as it appears to be more accurate and prognostic than CT. The role of FDG PET-CT throughout the management course in patients with lymphoma is explored in this review, with areas discussed that may limit the use of PET-CT imaging which clinicians should be familiar with to inform practice.

Allogeneic transplantation in the UK: an aggregation of marginal gains?

A number of advances in clinical practice that are considered routine in modern allogeneic transplant programmes lack definitive supporting evidence, partly because they may offer modest incremental benefits that are difficult to demonstrate in a statistically robust manner given the relatively small cohorts of patients who undergo such procedures. Nevertheless, these marginal gains probably contribute therapeutically meaningful overall benefit, particularly when aggregated. We review the evidence for a number of these practices in terms of impact on transplant outcomes, with particular reference to the setting of T cell depletion as widely practiced in the United Kingdom, including high resolution tissue typing, surveillance for and therapy of infectious complications, chimerism-directed immune modulation and more sensitive monitoring for residual or progressive disease.

Recent progress in managing graft-versus-host disease and viral infections following allogeneic stem cell transplantation

Despite recent reductions in transplant-related mortality, post-transplant complications such as graft-versus-host disease (GvHD) remain major obstacles to the successful application of allogeneic hematopoietic transplantation. Steroid-refractory GvHD has a poor outcome. Although there are a variety of new approaches to the treatment of refractory GvHD, many have limited evidence of efficacy. Other approaches appear to be unacceptably toxic. It would be preferable to improve GvHD prophylaxis. There is good evidence that rates of GvHD can be reduced without unacceptable reduction of the graft-versus-leukemia effect or compromising overall survival. However, prophylactic measures aimed at reducing T-cell numbers or functions are associated with high rates of reactivation of latent viruses. New technologies that allow rapid generation of virus-specific T-cells show promise to reduce the frequency and severity of such reactivations and have the potential to revolutionize the approach to post-transplant infectious complications.

Nonmyeloablative allogeneic stem cell transplantation for non-hodgkin lymphoma

Non-Hodgkin lymphomas constitute a heterogeneous group of hematologic malignancies with varying aggressiveness and many therapeutic options. Nonmyeloablative (NMA) conditioning has been the cornerstone of allogeneic adoptive immunotherapy for these diseases. This approach utilizes a reduced intensity preparative regimen to achieve engraftment with little toxicity. This allows for development of the immune graft-versus-lymphoma effect. Results depend on the histologic type of lymphoma, prognostic factors, patient characteristics, and chemosensitivity. For follicular lymphomas, NMA transplants are highly effective in patients with refractory or recurrent disease after the best chemoimmunotherapy available and who have a matched sibling or unrelated donor. In mantle cell lymphoma, autologous stem cell transplants are generally ineffective for patients with recurrent disease; we reported 6-year actuarial progression-free survival rate of 46%, using NMA allogeneic transplants. The indications of NMA transplants for diffuse large B-cell lymphoma and T-cell lymphomas are controversial; success has been reported in selected high-risk patients and those relapsing after an autologous transplantation who have chemosensitive disease. Considerations for the conditioning regimen, donor source, graft-versus-host disease prophylaxis, donor lymphocyte infusion, and relapse prevention methods are reviewed.

Risk-stratified adoptive cellular therapy following allogeneic hematopoietic stem cell transplantation for advanced chronic lymphocytic leukaemia

Following reduced intensity-conditioned allogeneic stem cell transplantation (RIC allo-SCT) for chronic lymphocytic leukaemia (CLL), there is an inverse relationship between relapse and extensive chronic graft-versus-host disease (GVHD). We evaluated outcomes in 50 consecutive patients with CLL using the approach of alemtuzumab-based RIC allo-SCT and pre-emptive donor lymphocyte infusions (DLI) for mixed chimerism or minimal residual disease (MRD), with the intention of reducing the risk of GVHD. Forty two patients had high-risk disease, including 30% with 17p deletion (17p-). Of patients who were not in complete remission (CR) entering transplant, 83% subsequently achieved MRD-negative CR. Both MRD detection and uncorrected mixed chimerism were associated with greater risks of treatment failure. Nine of sixteen patients receiving DLI for persistent or relapsed disease subsequently attained MRD-negative CR. With a median follow-up of 4.3 years, 4-year current progression-free survival was 65% and overall survival was 75% (60% and 61% in respectively, patients with 17p-). DLI was associated with a 29% cumulative incidence of severe GVHD and mortality of 6.4%. At last follow-up, 83% of patients in CR were off all immunosuppressive treatment. In conclusion, the directed delivery of allogeneic cellular therapy has the potential to induce durable remissions in high-risk CLL without incurring excessive GVHD.

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

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

Mini-BEAM is effective as a bridge to transplantation in patients with refractory or relapsed Hodgkin lymphoma who have failed to respond to previous lines of salvage chemotherapy but not in patients with salvage-refractory DLBCL

Patients with relapsed or refractory lymphoma can be cured with stem cell transplantation if they are shown to have disease that is responsive to salvage chemotherapy. Patients who fail to respond to first-line salvage chemotherapy tend to do very poorly. Here we report on 39 such patients who received mini-BEAM (carmustine, etoposide, cytarabine, melphalan) chemotherapy as second or subsequent-line salvage chemotherapy. Fifty-six percent of these patients had primary refractory disease and a further 28% had responses to first-line therapy that lasted <12 months. Seventy-two percent had progressive disease following the salvage chemotherapy administered immediately prior to mini-BEAM and the remaining 28% had stable disease. Overall there was a 38% response to mini-BEAM (complete response = 28%, partial response = 10%). Patients with Hodgkin lymphoma (HL) had a higher response rate compared to those with diffuse large B cell lymphoma (DLBCL) (63% vs. 20%). Seventy-four percent of HL patients were able to proceed to transplantation compared with 30% of patients with DLBCL. Mini-BEAM is a very effective bridge to transplantation in very poor risk patients with HL who have failed to respond to first-line salvage chemotherapy. Its efficacy in non-Hodgkin lymphoma is more modest.

Positron Emission Tomography in the Management of Hodgkin Lymphoma

Accurate imaging of lymphoma is essential for optimal management. Positron emission tomography (PET), by providing both anatomic and functional information, is fundamentally altering staging, monitoring of response, response assessment, and choice of treatment modality for lymphomas, including Hodgkin lymphoma. This imaging technique, when used carefully in conjunction with standard testing, increases the sensitivity of lesion detection, provides an opportunity to monitor the quality of response during treatment, permits separation of fibronecrotic scar tissue from viable tumor, and adds prognostic information. PET has become integral to modern lymphoma management, but as a relatively new diagnostic technique, it is still being studied and neither its full potential nor its major limitations are fully understood. Discussed herein are recent observations from clinical trials and single-center experiences with PET to explore its advantages and limitations from a clinician's point of view.

Stem cell transplantation for indolent lymphoma: a reappraisal

Allogeneic transplantation is established as a curative treatment for follicular lymphoma, but with considerable short and long-term morbidity and mortality. Data and controversies regarding conditioning regimen, donor source, GVHD prophylaxis, post transplant interventions and approaches to predict and reduce morbidity and mortality are reviewed. Total body irradiation is very effective but toxic and reduced intensity conditioning is often preferred though associated with somewhat higher rates of recurrence. The risk of chronic GVHD and its late sequelae can be markedly reduced by in-vivo T-cell depletion using alemtuzumab but also leads to somewhat higher incidence of disease recurrence. When using such treatment strategies, one can consider prophylactic or preemptive donor lymphocyte infusions or low toxicity medical treatment such as rituximab. Overall the long term outcomes, particularly survival and current progression free survival of patients undergoing allogeneic transplantation for indolent lymphoma have steadily improved and transplant can now often safely be considered up to the sixth decade of life. Outcomes of unrelated donor transplantation approach those of HLA-identical sibling transplant and even mismatched umbilical cord transplant can be considered in selected patients. The assessment of risks and benefits is aided by the use of various novel tools.

Current status of allogeneic transplantation for aggressive non-Hodgkin lymphoma

PURPOSE OF REVIEW

To provide a succinct update on the role of allogeneic stem cell transplantation (allo-SCT) in the management of patients with aggressive lymphomas. To clarify the indications for allogeneic transplantation vis-à-vis autologous transplant and to discuss the rationale and potential benefits of reduced intensity conditioning (RIC), nonmyeloablative (NMA) transplant, T-cell depletion and variations in graft vs. host disease (GVHD) prophylaxis.

RECENT FINDINGS

Considerable effort has been spent in developing transplant regimens with reduced toxicity and reduced GVHD. The role of allogeneic transplantation has also been redefined in light of advances in lymphoma classification, diagnostic methods, particularly PET scan and advances in transplant technology. Haplo and umbilical cord blood SCT allow identification of a donor for nearly all patients.

SUMMARY

In diffuse large B-cell lymphoma, the outcome of allo-SCT depends on patient characteristics and chemosensitivity. It is useful after failure of auto-SCT and in partial responses to salvage therapy. Allo-SCT may be the treatment of choice for advanced T-cell and natural killer cell lymphoma and for adult T-cell leukemia-lymphoma. Prophylactic or preemptive donor lymphocyte infusion may be useful, but requires controlled studies. RIC and NMA conditioning have reduced early toxicity but are associated with increased risk for disease recurrence. Promising data have been reported from a novel conditioning regimen combining NMA with ibritumomab tiuxetan. T-cell depletion reduces chronic GVHD but has some increase in rate of recurrence. Rapamycin may be associated with reduction in risk for disease recurrence.

Allogeneic stem cell transplantation after reduced intensity conditioning in patients with relapsed or refractory Hodgkin's lymphoma. Results of the HDR-ALLO study - a prospective clinical trial by the Grupo Español de Linfomas/Trasplante de Médula Osea (GEL/TAMO) and the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND

Although Hodgkin's lymphoma is a highly curable disease with modern chemotherapy protocols, some patients are primary refractory or relapse after first-line chemotherapy or even after high-dose therapy and autologous stem cell transplantation. We investigated the potential role of allogeneic stem cell transplantation in this setting.

DESIGN AND METHODS

In this phase II study 92 patients with relapsed Hodgkin's lymphoma and an HLA-identical sibling, a matched unrelated donor or a one antigen mismatched, unrelated donor were treated with salvage chemotherapy followed by reduced intensity allogeneic transplantation. Fourteen patients showed refractory disease and died from progressive lymphoma with a median overall survival after trial entry of 10 months (range, 6-17). Seventy-eight patients proceeded to allograft (unrelated donors, n=23). Fifty were allografted in complete or partial remission and 28 in stable disease. Fludarabine (150 mg/m(2) iv) and melphalan (140 mg/m(2) iv) were used as the conditioning regimen. Anti-thymocyte globulin was additionally used as graft-versus-host-disease prophylaxis for recipients of grafts from unrelated donors.

RESULTS

The non-relapse mortality rate was 8% at 100 days and 15% at 1 year. Relapse was the major cause of failure. The progression-free survival rate was 47% at 1 year and 18% at 4 years from trial entry. For the allografted population, the progression-free survival rate was 48% at 1 year and 24% at 4 years. Chronic graft-versus-host disease was associated with a lower incidence of relapse. Patients allografted in complete remission had a significantly better outcome. The overall survival rate was 71% at 1 year and 43% at 4 years.

CONCLUSIONS

Allogeneic stem cell transplantation can result in long-term progression-free survival in heavily pre-treated patients with Hodgkin's lymphoma. The reduced intensity conditioning approach significantly reduced non-relapse mortality; the high relapse rate represents the major remaining challenge in this setting. The HDR-Allo trial was registered in the European Clinical Trials Database (EUDRACT, https://eudract.ema.europa.eu/) with number 02-0036.

Stem cell transplantation for indolent lymphoma and chronic lymphocytic leukemia

The indolent lymphomas, including chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) remain incurable with standard therapy. Autologous hematopoietic stem cell transplantation (HSCT) is feasible and has low treatment-related mortality in follicular lymphoma, but there are questions relating to optimal timing of the procedure, conditioning regimen, and late effects. Myeloablative allogeneic HSCT is associated with high treatment-related morbidity and mortality, few late relapses, but is applicable to only a small number of patients. The major focus of HSCT in these lymphomas has been with reduced-intensity conditioning (RIC) allogeneic HSCT, which is applicable to the age distribution of these diseases and which exploits the graft-versus-lymphoma effect in these diseases. Steps to further decrease the morbidity and mortality of the RIC HSCT and in particular to reduce the incidence of chronic extensive graft-versus-host disease (GVHD) while maintaining tumor control remain the major focus. Many potential treatments are available for indolent lymphomas and CLL, and appropriate patient selection and the timing of HSCT remain controversial. The use of HSCT must always be weighed against the risk of the underlying disease, particularly in a setting where improvements in treatment are leading to improved outcome.

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.

Allogeneic transplantation for lymphoma

Historically, high levels of treatment-related mortality restricted the use of standard myeloablative allogeneic stem-cell transplantation to a minority of young and fit patients with lymphoma. Over the last decade, increasing numbers of patients with lymphoma have undergone allogeneic stem-cell transplantation using reduced-intensity protocols that are associated with lower toxicity and reduced transplantation-related mortality. Graft-versus-lymphoma effects contribute to the therapeutic effect in patients with indolent or Hodgkin's lymphoma. However, definitive evidence for efficacy of this strategy is lacking because most patients undergoing transplantation do so after failure of several lines of treatment, leaving no obvious comparator arm for randomized controlled studies. Nevertheless, encouraging results have been reported for selected patients for most lymphoma subtypes, with pretransplantation disease status emerging as the most important predictor of outcome. The major long-term toxicity is chronic graft-versus-host disease that contributes to ill health in a significant minority of survivors. In the future, risk-adapted trials that evaluate reduced-intensity allogeneic transplantation in patients with predicted poor outcomes with immunochemotherapy or autologous transplantation will be important in determining the role of this treatment.

Donor Lymphocyte Infusions Modulate Relapse Risk in Mixed Chimeras and Induce Durable Salvage in Relapsed Patients After T-Cell–Depleted Allogeneic Transplantation for Hodgkin's Lymphoma

Purpose

Reduced-intensity conditioning has minimized nonrelapse-related mortality rates after allogeneic transplantation in patients with Hodgkin's lymphoma, and relapse has now become the major cause for treatment failure. We aimed to assess the impact of donor lymphocyte infusions (DLIs) on relapse incidence when administered for mixed chimerism and their utility as salvage therapy when given for relapse.

Patients and Methods

This study reports the outcomes of 76 consecutive patients with multiply relapsed or refractory Hodgkin's lymphoma who underwent allogeneic transplantation that incorporated in vivo T-cell depletion. Forty-two patients had related donors and 34 had unrelated donors. DLIs were administered in a dose-escalating fashion to 22 patients for mixed chimerism (median time of first dose, 9 months post-transplantation) and to 24 patients for relapse.

Results

Three-year donor lymphocyte–related mortality was 7%, relating mainly to the induction of graft-versus-host disease. Nineteen (86%) of 22 patients receiving donor lymphocytes for mixed chimerism converted to full donor status. Four-year relapse incidence was 5% in these 22 patients compared with 43% in patients who remained relapse free but full donor chimeras at 9 months post-transplantation (P = .0071). Nineteen (79%) of 24 patients receiving donor lymphocytes for relapse responded (14 complete responses, five partial responses). Four-year overall survival from relapse was 59% in recipients of donor lymphocytes, contributing to a 4-year overall survival from transplantation of 64% and a 4-year current progression-free survival of 59% in all 76 patients.

Conclusion

These data demonstrate the potential for allogeneic immunotherapy with donor lymphocytes both to reduce relapse risk and to induce durable antitumor responses in patients with Hodgkin's lymphoma after hematopoietic stem-cell transplantation that incorporates in vivo T-cell depletion.

T-cell-depleted allogeneic transplant without donor leukocyte infusions results in excellent long-term survival in patients with multiply relapsed Lymphoma. Predictors for survival after transplant relapse

We analyzed 67 patients with lymphoma who received alemtuzumab-based conditioning regimens for allogeneic stem cell transplant and no post-transplant DLI. The median age was 54 (24-70), 43% had unrelated donors, 34% had chemotherapy refractory disease, and 25% had an elevated LDH. With a median follow-up for survivors of 35 months, the estimated 3-year progression-free survival (PFS) and overall survival (OS) were 30% and 47%, respectively. Chemosensitivity by CT and pre-transplant LDH were independent prognostic factors for both overall survival and progression-free survival. Patient age, performance status, donor type, lymphoma subtype, disease sensitivity by PET, and conditioning regimen did not correlate with PFS and OS. Patients who relapsed greater than 6 months after allogeneic transplant were frequently able to re-enter a subsequent durable remission. Our experience confirms the curative potential of alemtuzumab-containing RIC regimens for allogeneic HCT in patients with relapsed lymphoma without prophylactic DLI. An elevated pre-transplant LDH and chemorefractory disease prior to transplant confer a worse prognosis, while PET scan findings do not have this same implication. Patients who relapse greater than 6 months after their transplant are likely to achieve a subsequent remission with any of a variety of interventions, suggesting that GVL effects can be operative even after recurrence. Our outcomes challenge the utility of the common practice of prophylactic DLI after T-depleted transplant for lymphoma.

CD8+CD44(hi) but not CD4+CD44(hi) memory T cells mediate potent graft antilymphoma activity without GVHD

Allogeneic hematopoietic cell transplantation can be curative in patients with leukemia and lymphoma. However, progressive growth of malignant cells, relapse after transplantation, and graft-versus-host disease (GVHD) remain important problems. The goal of the current murine study was to select a freshly isolated donor T-cell subset for infusion that separates antilymphoma activity from GVHD, and to determine whether the selected subset could effectively prevent or treat progressive growth of a naturally occurring B-cell lymphoma (BCL(1)) without GVHD after recipients were given T cell-depleted bone marrow transplantations from major histocompatibility complex-mismatched donors. Lethal GVHD was observed when total T cells, naive CD4(+) T cells, or naive CD8(+) T cells were used. Memory CD4(+)CD44(hi) and CD8(+)CD44(hi) T cells containing both central and effector memory cells did not induce lethal GVHD, but only memory CD8(+) T cells had potent antilymphoma activity and promoted complete chimerism. Infusion of CD8(+) memory T cells after transplantation was able to eradicate the BCL(1) lymphoma even after progressive growth without inducing severe GVHD. In conclusion, the memory CD8(+) T-cell subset separated graft antilymphoma activity from GVHD more effectively than naive T cells, memory CD4(+) T cells, or memory total T cells.