Evaluation and Management of Disease Transformation in Waldenström Macroglobulinemia

Histologic transformation (HT) to diffuse large B-cell lymphoma occurs rarely in Waldenström macroglobulinemia, with higher incidence in MYD88 wild-type patients. HT is suspected clinically when rapidly enlarging lymph nodes, elevated lactate dehydrogenase levels, or extranodal disease occur. Histologic assessment is required for diagnosis. HT carries a worse prognosis compared with nontransformed Waldenström macroglobulinemia. A validated prognostic score based on three adverse risk factors stratifies three risk groups. The most common frontline treatment is chemoimmunotherapy, such as R-CHOP. Central nervous system prophylaxis should be considered if feasible and consolidation with autologous transplant should be discussed in fit patients responding to chemoimmunotherapy.

Transformed Waldenström Macroglobulinemia: Update on Diagnosis, Prognosis and Treatment

Histological transformation (HT) to an aggressive lymphoma results from a rare evolution of Waldenström macroglobulinemia (WM). A higher incidence of transformation events has been reported in MYD88 wild-type WM patients. HT in WM can be histologically heterogeneous, although the diffuse large B-cell lymphoma of activated B-cell subtype is the predominant pathologic entity. The pathophysiology of HT is largely unknown. The clinical suspicion of HT is based on physical deterioration and the rapid enlargement of the lymph nodes in WM patients. Most transformed WM patients present with elevated serum lactate dehydrogenase (LDH) and extranodal disease. A histologic confirmation regarding the transformation to a higher-grade lymphoma is mandatory for the diagnosis of HT, and the choice of the biopsy site may be dictated by the findings of the 18fluorodeoxyglucose-positron emission tomography/computed tomography. The prognosis of HT in WM is unfavorable, with a significantly inferior outcome compared to WM patients without HT. A validated prognostic score based on 3 adverse risk factors (elevated LDH, platelet count < 100 × 109/L and any previous treatment for WM) stratifies patients into 3 risk groups. The most common initial treatment used is a chemo-immunotherapy (CIT), such as R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). The response duration is short and central nervous system relapses are frequent. Whether autologous stem cell transplantation could benefit fit patients responding to CIT remains to be studied.

A new conditioning regimen with chidamide, cladribine, gemcitabine and busulfan significantly improve the outcome of high-risk or relapsed/refractory non-Hodgkin's lymphomas

Previous studies highlight the need for a more active conditioning therapy in high-risk or refractory and relapsed lymphomas. Our preclinical research shows that histone deacetylase inhibitors, such as either vorinostat or chidamide, sensitize lymphoma cells to the cytotoxic combination of cladribine, gemcitabine and busulfan, leading to cell apoptosis. To evaluate the efficacy of this chidamide-cladribine-gemcitabine-busulfan (ChiCGB) combination as a new conditioning therapy, we conducted a Phase II trial, as described here. Patients with high-risk, relapsed/refractory lymphomas received ChiCGB as conditioning therapy, after transplantation with autologous peripheral stem cells. The sample comprised 105 patients in total: 60 with B-cell non-Hodgkin lymphomas (B-NHL) and 45 with T-cell or natural killer/T-cell lymphoma (NK/T). All patients eventually achieved full hematopoietic recovery. Neutrophils and platelets were engrafted at a median of 10 days (8-14) and 13 days (8-38), respectively. There was no transplant-related mortality within 100 days of transplant. Neutropenic fever, mucositis and atopic dermatitis were the observed nonhematologic toxicities. At a median follow-up of 35.4 months, 80.6% of the patients presented with no tumor progression, and the overall survival (OS) reached as high as 86.1%. Concerning the OS rate, 94.5% of patients with B-NHL and 75.4% of patients with T-cell or NK/T lymphomas survived. These findings demonstrate the safety and validity of the proposed combined therapy for high-risk and refractory/relapsed lymphomas. Our study was registered on the Clinical Trial Registry (clinicaltrials.gov, NCT03151876).

Modified conditioning regimen with idarubicin followed by autologous hematopoietic stem cell transplantation for invasive B-cell non-Hodgkin's lymphoma patients

High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (ASCT) is still a consolidation treatment choice for relapsed/refractory B-cell non-Hodgkin’s lymphoma (NHL) patients and some aggressive B-cell NHL as frontline therapy. Due to the shortage of carmustine, we switched to idarubicin-substituted BEAC (IEAC) conditioning regimen. We retrospectively compared the outcomes of 72 aggressive B-cell NHL patients treated with IEAC or BEAC regimens followed by ASCT as upfront consolidative treatment. The median time to neutrophil and platelet reconstitution showed no difference between IEAC and BEAC groups. IEAC regimen was well tolerated without increase of adverse events. Transplant-related mortality didn’t occur. The overall survival (OS) and progression-free survival (PFS) of IEAC group (33 and 23 months) were a little longer than that of BEAC group (30 and 18 months). However, due to the small sample numbers, there’s no significant difference in OS and PFS between IEAC and BEAC group with DLBCL or MCL. Multivariate analysis showed that AnnArbor staging, IPI score, lactate dehydrogenase level, remission of disease, modified regimen were related with PFS and OS. In conclusion, IEAC regimen was well tolerated and replacement with idarubicin could be an alternative when carmustine was not available.

Autologous stem cell transplantation for untreated transformed indolent B-cell lymphoma in first remission: an international, multi-centre propensity-score-matched study

High-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT) are used as consolidation in first remission (CR1) in some centres for untreated, transformed indolent B-cell lymphoma (Tr-iNHL) but the evidence base is weak. A total of 319 patients with untreated Tr-iNHL meeting prespecified transplant eligibility criteria [age <75, LVEF ≥45%, no severe lung disease, CR by positron emission tomography or computed tomography ≥3 months after at least standard cyclophosphamide, doxorubicin, vincristine and prednisolone with rituximab (R-CHOP) intensity front-line chemotherapy] were retrospectively identified. Non-diffuse large B-cell lymphoma transformations were excluded. About 283 (89%) patients had follicular lymphoma, 30 (9%) marginal-zone lymphoma and six (2%) other subtypes. Forty-nine patients underwent HDC/ASCT in CR1, and a 1:2 propensity-score-matched cohort of 98 patients based on age, stage and high-grade B-cell lymphoma with MYC, BCL2 and/or BCL6 rearrangements (HGBL-DH) was generated. After a median follow-up of 3·7 (range 0·1-18·3) years, ASCT was associated with significantly superior progression-free survival [hazard ratio (HR) 0·51, 0·27-0·98; P = 0·043] with a trend towards inferior overall survival (OS; HR 2·36;0·87-6·42; P = 0·1) due to more deaths from progressive disease (8% vs. 4%). Forty (41%) patients experienced relapse in the non-ASCT cohort - 15 underwent HDC/ASCT with seven (47%) ongoing complete remission (CR); 10 chimeric antigen receptor-modified T-cell (CAR-T) therapy with 6 (60%) ongoing CR; 3 allogeneic SCT with 2 (67%) ongoing CR. Although ASCT in CR1 improves initial duration of disease control in untreated Tr-iNHL, the impact on OS is less clear with effective salvage therapies in this era of CAR-T.

NCCN Guidelines Insights: B-Cell Lymphomas, Version 3.2019

Diffuse large B-cell lymphomas (DLBCLs) and follicular lymphoma (FL) are the most common subtypes of B-cell non-Hodgkin's lymphomas in adults. Histologic transformation of FL to DLBCL (TFL) occurs in approximately 15% of patients and is generally associated with a poor clinical outcome. Phosphatidylinositol 3-kinase (PI3K) inhibitors have shown promising results in the treatment of relapsed/refractory FL. CAR T-cell therapy (axicabtagene ciloleucel and tisagenlecleucel) has emerged as a novel treatment option for relapsed/refractory DLBCL and TFL. These NCCN Guidelines Insights highlight important updates to the NCCN Guidelines for B-Cell Lymphomas regarding the treatment of TFL and relapsed/refractory FL and DLBCL.

Mitoxantrone-melphalan conditioning regimen for autologous stem cell transplantation in relapsed/refractory lymphoma

Background/aim

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) has become the standard approach for patients with relapsed/refractory Hodgkin’s lymphoma (HL) or non-Hodgkin’s lymphoma (NHL). In this study, we report the outcome of the mitoxantrone-melphalan conditioning regimen for lymphoma.

Materials and methods

The study group included 53 patients who were relapsed/refractory HL (n = 14) and NHL (n = 39) and received mitoxantrone and melphalan followed by ASCT. The transplant regimen consisted of mitoxantrone (60 mg/m2) and melphalan (180 mg/m2) followed by peripheral blood stem cell infusion (PBSC).

Results

Prior to high-dose chemotherapy, 37.7% of the patients were in complete remission (CR) and 45.3% were in partial remission (PR), and 17% had stable or progressive disease. After high-dose chemotherapy and PBSC, 44 out of 51 patients achieved CR (86.2%). CR was achieved in 24 out of 33 patients (72.7%) who were transplanted in a marginally active phase of the disease. At a median followup of 25.4 months (1.8–131.3 months) after ASCT, 13 patients relapsed/progressed and 8 patients died. The estimated 2-year overall survival (OS) was 81.9%, and event-free survival (EFS) was 59.3%.

Conclusion

High-dose chemotherapy followed by ASCT is an effective conditioning regimen in relapsed/refractory lymphoma patients who are undergoing ASCT.

Strategies to improve outcomes of autologous hematopoietic cell transplant in lymphoma

High-dose chemotherapy and autologous hematopoietic cell transplantation (HDT-AHCT) remains an effective therapy in lymphoma. Over the past several decades, HDT with BEAM (carmustine, etoposide, cytarabine, and melphalan) and CBV (cyclophosphamide, carmustine, and etoposide) have been the most frequently used preparatory regimens for AHCT in Hodgkin (HL) and non-Hodgkin lymphoma (NHL). This article reviews alternative combination conditioning regimens, as well as novel transplant strategies that have been developed, to reduce transplant-related toxicity while maintaining or improving efficacy. These data demonstrate that incorporation of maintenance therapy posttransplant might be the best way to improve outcomes.

Novel acquisitions on biology and management of transformed follicular lymphoma

Follicular lymphoma (FL) generally has an indolent clinical course, but in some patients, a histological transformation (HT) into aggressive entities may take place and often lead to a poorer survival. The rituximab era has seen an improved outcome of FL, including those with HT. The current treatment strategies for transformed FL are based on immunochemotherapy for the cases with HT at the time of diagnosis or as the first event after watchful waiting. Patients transforming after prior treatment of FL usually benefit from autologous stem cell transplant. Unfortunately, early assessment of the transformation risk remains elusive. Recent studies delved the mechanisms of HT, showing that this is a complex process, resulting from a number of epigenetic and genetic lesions occurring in the tumour cell population as well as progressive changes in the tumour microenvironment. This novel knowledge has prompted clinical investigations on a variety of new therapeutic strategies.

Similar prognosis of transformed and de novo diffuse large B-cell lymphomas in patients treated with immunochemotherapy

BACKGROUND

The prognosis of diffuse large B-cell lymphomas (DLBCL) transformed from indolent lymphoma (TL) has been considered poorer than that of de novo DLBCL. However, it seems to have improved since the introduction of rituximab.

PATIENTS AND METHODS

We compared the characteristics (including the cell-of-origin), and the prognosis of 29 patients with TL and 101 with de novo DLBCL treated with immunochemotherapy.

RESULTS

Patients with TL and de novo DLBCL had similar characteristics. All TL cases evolving from follicular lymphoma were germinal-center B-cell-like, while those TL from marginal zone lymphoma or chronic lymphocytic leukemia were non-germinal-center B-cell-like. The complete response rate was similar in TL and de novo DLBCL (62 vs. 66%, P=.825). The 5-year overall and progression-free survival probabilities (95% CI) were 59% (40-78) and 41% (22-60) for TL and 63% (53-73) and 60% (50-70) for de novo DLBCL, respectively (P=.732 for overall survival and P=.169 for progression-free survival).

CONCLUSION

In this study, the prognosis of TL and de novo DLBCL treated with immunochemotherapy was similar. The role of intensification with stem cell transplantation in the management of TL may be questionable in the rituximab era.

The role of stem-cell transplantation in the treatment of marginal zone lymphoma

High-dose chemotherapy and autologous stem-cell transplantation (ASCT) is standard therapy in relapsed/refractory aggressive lymphoma. The optimal therapy of relapsed/refractory disseminated marginal-zone lymphoma (MZL) has not been defined. Limited data on ASCT in this setting suggests outcomes are similar to what is expected in follicular lymphoma. International guidelines suggest that ASCT should be considered in follicular lymphoma in second or subsequent remission, in particular in high-risk disease, or following disease transformation. These guidelines can be extrapolated to MZL. ASCT is not considered curative but a subset of patients achieve very long remissions. The major concern is the occurrence of secondary malignancies possibly related to total-body irradiation. Allogeneic SCT is usually considered after failure of ASCT, but can also be considered upfront in younger patients seeking curative approach. The introduction of novel/targeted therapies may change the role and timing SCT may have in the treatment algorithm of indolent lymphomas.

Risk Factors and Outcomes for Patients With Follicular Lymphoma Who Had Histologic Transformation After Response to First-Line Immunochemotherapy in the PRIMA Trial

Purpose

To study the outcome of histologic transformation (HT) in a large prospective cohort of patients with follicular lymphoma (FL) who previously responded to immunochemotherapy.

Patients and Methods

After a median 6-year follow-up of 1,018 randomly assigned patients from the PRIMA trial, disease progression was observed in 463 patients, 194 of whom had histologic documentation.

Results

Forty patients had histology consistent with HT, and 154 had untransformed FL (median time to recurrence, 9.6 v 22.8 months, respectively; P = .018). Thirty-seven percent of biopsies performed during the first year of follow-up showed HT corresponding to 58% of all HTs. Altered performance status, anemia, high lactate dehydrogenase level, “B” symptoms, histologic grade 3a, and high Follicular Lymphoma International Prognostic Index scores at diagnosis were identified as HT risk factors. Response (complete v partial) to immunochemotherapy or rituximab maintenance had no impact on the risk of HT. After salvage treatment, patients with HT had less frequent complete response (50.3% v 67.4%; P = .03) and more disease progression (28.2% v 9.6%; P < .001) than patients without HT. Estimated overall survival for the patients with HT was poorer (median, 3.8 v 6.4 years; hazard ratio, 3.9; 95% CI, 2.2 to 6.9). Autologous stem cell transplantation improved the outcomes of patients with HT (median overall survival, not reached v 1.7 years) but not of patients with persistent FL histology.

Conclusion

HT in patients with FL who previously responded to immunochemotherapy is an early event associated with a poor outcome that may deserve intensive salvage with autologous stem cell transplantation. These data emphasize the necessity for biopsy at the first recurrence of FL.

Ifosfamide, Cisplatin or Carboplatin, and Etoposide (ICE)-based Chemotherapy for Mobilization of Autologous Peripheral Blood Stem Cells in Patients with Lymphomas

Background:

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is a promising approach for lymphomas. This study aimed to evaluate the effect of ifosfamide, cisplatin or carboplatin, and etoposide (ICE)-based regimen as a mobilization regimen on relapsed, refractory, or high-risk aggressive lymphoma.

Methods:

From June 2001 to May 2013, patients with lymphomas who mobilized by ICE-based regimen for ASCT were analyzed in this retrospective study. The results of the autologous peripheral blood stem cells collection, toxicity, engraftment after ICE-based mobilization regimen were analyzed in this study. Furthermore, risk factors for overall survival (OS) and progression free survival (PFS) were evaluated by univariate analysis.

Results:

The stem cells were mobilized using ICE-based regimen plus rituximab or ICE-based regimen alone in 12 patients and 54 patients, respectively. The results of stem cell mobilization were excellent. Ninety-seven percentages of the patients had the stem cell collection of at least 2.0 × 10⁶ CD34⁺ cells/kg and 68% had at least 5 × 10⁶ CD34⁺ cells/kg. Fifty-eight percentage of the patients experienced Grade 4 neutropenia, 20% developed febrile neutropenia, and only 12% had Grade 4 thrombocytopenia. At a median follow-up of 63.8 months, the 5-year PFS and OS were 64.4% and 75.3%, respectively.

Conclusion:

ICE is a powerful regimen for stem cell mobilization in patients with lymphomas.

Consolidative Radioimmunotherapy After Chemoimmunotherapy in Patients With Histologic Transformation of Indolent Non-Hodgkin Lymphoma

INTRODUCTION

Histologic transformation (HT) of indolent non-Hodgkin lymphomas is an event that results in considerable morbidity and mortality. The introduction of chemoimmunotherapy regimens has resulted in an improvement in the management of this disease, and consolidation of responses with autologous stem cell transplantation appears efficacious. Many patients are not eligible for high-dose therapy, however. Radioimmunotherapy (RIT) has demonstrated single-agent efficacy in HT and can be used safely as consolidation after chemoimmunotherapy. For these reasons, RIT consolidation after chemoimmunotherapy induction has been our standard treatment approach at the University of Rochester for patients with HT who were ineligible for autologous stem cell transplantation.

PATIENTS AND METHODS

A retrospective cohort study was performed to describe the clinical outcomes of these patients. Twenty-one patients were identified who received RIT consolidation. The Kaplan-Meier method was used to estimate the distributions of overall survival and progression-free survival. Comparisons were made between patients with pathologic HT and the combination of clinical HT and composite lymphoma using the log-rank test to compare survival curves.

RESULTS

The median overall survival of the cohort was 84 months, and progression-free survival was 38 months. The major toxicity was myelosuppression, and 2 deaths were attributed to therapy. One case of therapy-related acute myeloid leukemia was noted.

CONCLUSION

In a population of patients ineligible for high-dose therapy with autologous stem cell support, consolidation of response to chemoimmunotherapy with RIT was well tolerated and should be considered in patients with disease responsive to induction therapy.

Salvage chemotherapy and autologous stem cell transplantation for transformed indolent lymphoma: a subset analysis of NCIC CTG LY12

The treatment of transformed indolent lymphoma (TRIL) often includes salvage chemotherapy (SC) and autologous stem cell transplant (ASCT). NCIC CTG LY12 is a randomized phase 3 trial comparing gemcitabine, dexamethasone, and cisplatin (GDP) with dexamethasone, cytarabine, and cisplatin (DHAP) before ASCT. This analysis compares the results of SC and ASCT for TRIL with de novo diffuse large B-cell lymphoma (DLBCL). Six-hundred nineteen patients with relapsed/refractory aggressive non-Hodgkin lymphoma were randomized to GDP or DHAP; 87 patients (14%) had TRIL and 429 (69%) had DLBCL. The response rate to SC was 47% in TRIL and 45% in DL (P = .81). Transplantation rates were similar: TRIL 53% and DL 52% (P = 1.0). With a median follow-up of 53 months, 4 year overall survival was 39% for TRIL and 41% for DL (P = .78); 4 year event-free survival (EFS) was 27% for TRIL and 27% for DL (P = .83). Post-ASCT, 4-year EFS was 45% for TRIL and 46% for DL. Histology (TRIL or DL) was not a predictor of any outcome in multivariate models. Patients with relapsed or refractory TRIL and DLBCL have similar outcomes with SC and ASCT; this therapy should be considered the standard of care for patients with TRIL who have received prior systemic chemotherapy. NCIC CTG LY12 is registered at ClinicalTrials.gov as #NCT00078949.

Outcomes of transformed follicular lymphoma in the modern era: a report from the National LymphoCare Study (NLCS)

We assessed the incidence, prognostic features, and outcomes associated with transformation of follicular lymphoma (FL) among 2652 evaluable patients prospectively enrolled in the National LymphoCare Study. At a median follow-up of 6.8 years, 379/2652 (14.3%) patients transformed following the initial FL diagnosis, including 147 pathologically confirmed and 232 clinically suspected cases. Eastern Cancer Oncology Group performance status >1, extranodal sites >1, elevated lactate dehydrogenase, and B symptoms at diagnosis were associated with transformation risk. Relative to observation, patients initiating treatment at diagnosis had a reduced risk of transformation (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.46-0.75). The risk of transformation was similar in patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone compared with rituximab, cyclophosphamide, vincristine, and prednisone (adjusted HR, 0.94; 95% CI, 0.62-1.42). Maintenance rituximab was associated with reduced transformation risk (HR, 0.67; 95% CI, 0.46-0.97). Five-year survival from diagnosis was significantly worse for patients with vs without transformation (75%, 95% CI, 70-79 vs 85%, 95% CI, 83-86). The median overall survival post-transformation was 5 years. Forty-seven patients with evidence of transformation at the time of diagnosis shared similar prognostic factors and survival rates to those without transformation. Improved outcomes for transformation in the modern era are suggested by this observational study. This trial is registered at www.clinicaltrials.gov as #NCT00097565.

Impact of prior treatment on outcome of transformed follicular lymphoma and relapsed de novo diffuse large B cell lymphoma: a retrospective multicentre analysis

Transformation of follicular lymphoma (FL) into aggressive disease and relapse of de novo diffuse large B cell lymphoma (DLBCL) are considered highly unfavourable events. However, most published data were acquired when rituximab was not routinely used. We retrospectively analysed 50 patients with transformed FL (tFL) in a multicenter study and compared them to 50 individuals with relapsed DLBCL (rDLBCL) who all obtained rituximab for the treatment of their disease. Our goal was to identify factors that predict a more favourable prognosis. After a median follow-up of 5.4 years from diagnosis, there was no significant difference in median overall survival (OS) from the date of transformation (tFL) or date of the first relapse (rDLBCL) (1.9 versus 3.9 years, P = .542). Of note, 5-year OS of patients with tFL was 46 %. Follicular lymphoma patients, treatment naïve prior to transformation, fared significantly better than pretreated patients (median not reached versus 1.4 years, P = .014). Regarding rDLBCL, female gender (13.9 versus 1.8 years, P = .019) and absence of rituximab prior to the first relapse (14.0 versus 1.8 years, P = .035) were favourable prognostic factors in a uni- and multivariate analysis. Only a proportion of patients received high-dose chemotherapy with autologous stem cell transplantation (HDT-ASCT), i.e. 38 and 52 % of patients with tFL and rDLBCL, respectively. Our data indicate that a favourable prognosis is conferred by treatment naivety in tFL and by rituximab naivety in rDLBCL. In contrast, we did not find a prognostic impact of HDT-ASCT in our series.

Transformed follicular non-Hodgkin lymphoma

Histologic transformation of follicular lymphoma to an aggressive non-Hodgkin lymphoma is a critical biologic event with profound implications on the natural history of this otherwise indolent disease. Recent insights into the genetic and epigenetic basis of transformation have been described, with the recognition of pivotal events governing the initiation and persistence of tumor evolution. Outcomes of patients with transformed lymphoma have historically been poor; however, several studies in the rituximab era suggest that survival may be more favorable than previously recognized. This review highlights our current understanding of transformed follicular lymphoma biology and pathogenesis, current treatment, and future directions.

Limited clinical benefit for surveillance PET-CT scanning in patients with histologically transformed lymphoma in complete metabolic remission following primary therapy

The optimum follow-up of patients with transformed indolent lymphoma (TrIL) is not well defined. We sought to determine the utility of surveillance positron emission tomography-computed tomography (PET-CT) in patients with TrIL achieving complete metabolic remission (CMR) after primary therapy. We performed a retrospective analysis of patients with TrIL treated at Peter MacCallum Cancer Centre between 2002 and 2012 who achieved CMR after primary therapy who had ≥1 subsequent surveillance PET-CT. Of 55 patients with TrIL, 37 (67 %) received autologous stem cell transplantation as consolidation following chemoimmunotherapy. After a median follow-up of 34 (range 3-101) months, the actuarial 3-year progression-free (PFS) and overall survival (OS) were 77 % (95 %CI 62-86 %) and 88 % (75-94 %), respectively. Of 180 surveillance PET-CT scans, there were 153 true negatives, 4 false positives, 1 false negative, 7 indeterminate and 15 true positives. Considering indeterminate scans as false positives, the specificity of PET-CT for detecting relapse was 94 %, sensitivity was 83 %, positive predictive value was 63 % and negative predictive value was 98 %. All seven subclinical (PET detected) relapses were of low-grade histology; in contrast, all nine relapses with diffuse large B cell lymphoma (DLBCL) were symptomatic. In our cohort of patients with TrIL achieving CMR, PET-CT detected subclinical low-grade relapses but all DLBCL relapses were accompanied by clinical symptoms. Thus, surveillance imaging of patients with TrIL achieving CMR is of limited clinical benefit. PET-CT should be reserved for evaluation of clinically suspected relapse.