High-dose therapy and autologous stem cell transplant for transformed non-Hodgkin lymphoma in the rituximab era

Role of Salvage Radiation Treatment of Relapses in Relapsed/Refractory Diffuse Large B Cell Lymphoma Post-Autologous Stem Cell Transplant

PURPOSE

Approximately 50% of patients with relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL) will relapse post-autologous stem cell transplant (ASCT), and the role of salvage therapy is not well defined. We examined radiation therapy (RT) as salvage treatment in this patient population.

MATERIALS AND METHODS

A retrospective review of patients with DLBCL who had an ASCT during 2004 to 2016 and subsequently relapsed was performed. Clinical and pathologic characteristics were collected, including detailed information regarding post-ASCT treatment. Response rates were tabulated and survival analysis was performed, stratified by salvage modality.

RESULTS

A total of 165 patients with R/R DLBCL who relapsed after ASCT were identified; 91 of these patients received salvage chemotherapy as their first line of relapse therapy, and 14 received salvage radiation. Median salvage RT dose was 36 Gy (range, 24-50). The objective response rate with salvage chemotherapy and RT was 53.0% and 78.5%, respectively (P = 0.07), and the complete response rate was 31.3% and 57.1%, respectively (P = 0.06). Median follow-up among living patients was 48.9 months (range, 4.8-136.17). Among patients with one site of relapse post-ASCT, median overall survival in patients who received salvage RT was significantly improved (P = 0.008) relative to chemotherapy (not reached [95% confidence interval {CI}, 8.4-not reached] versus 10.0 months [95% CI, 5.3-17.8]). Median progression-free survival in patients who received salvage RT was not significantly different (P = 0.16) relative to chemotherapy (8.4 months [95% CI, 2.5-47.7] versus 3.9 months [95% CI, 2.4-8.5]).

CONCLUSIONS

Patients who received RT as first salvage therapy post-ASCT, particularly with localized disease, had favorable oncologic outcomes. Future studies are needed to understand which patients with R/R DLBCL who relapse after ASCT may benefit from early salvage RT versus chemotherapy.

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.

Real world data on histological transformation in patients with follicular lymphoma: incidence, clinico-pathological risk factors and outcome in a nationwide Danish cohort

We investigated incidence, risk factors and outcome for follicular lymphoma (FL) patients with histologic transformation (HT) found at primary diagnosis (discordant/composite, dc-tFL) or sequentially (s-tFL). Between 2000 and 2015, 2773 patients were identified. The majority of patients (2252, 81%) did not experience HT (nt-FL), while 224 (8%) had dc-tFL and 297 (11%) s-tFL. The risk of HT was 2.2% per year and 9.6% at 5 years. Age ≥60, a high FLIPI risk score and LDH-elevation were associated with increased risk of HT. Calculated from primary diagnosis and compared with nt-FL, 5-year overall survival (OS) was inferior in both s-tFL and dc-tFL (nt-FL: 82%, s-tFL: 68%, dc-tFL: 68%; p = .001), whereas 5-year progression-free survival (PFS) was worse only in s-tFL (s-tFL: 18%, dc-tFL: 58%, nt-FL: 60%). Calculated from time of HT, s-tFL had inferior outcome compared to dc-tFL for both OS (s-tFL: 47%, dc-tFL: 68%, p = .001) and PFS (s-tFL: 35%, dc-tFL: 58%, p = .001).

Impact of concurrent indolent lymphoma on the clinical outcome of newly diagnosed diffuse large B-cell lymphoma

Some patients with diffuse large B-cell lymphoma (DLBCL) present with a concurrent indolent lymphoma at diagnosis. Their outcomes in the rituximab era are not fully defined. Using a prospectively followed cohort of 1324 newly diagnosed DLBCL patients treated with immunochemotherapy, we defined the prevalence, characteristics, and outcome of DLBCL with concurrent indolent lymphoma. Compared with patients with DLBCL alone (n = 1153; 87.1%), patients with concurrent DLBCL and follicular lymphoma (FL) (n = 109; 8.2%) had fewer elevations in lactate dehydrogenase, lower International Prognostic Index (IPI), and predominantly germinal center B-cell-like (GCB) subtype, whereas patients with concurrent DLBCL and other indolent lymphomas (n = 62; 4.7%) had more stage III-IV disease and a trend toward higher IPI and non-GCB subtype. After adjusting for IPI, patients with concurrent DLBCL and FL had similar event-free survival (EFS) (hazard ratio [HR] = 0.95) and a trend of better overall survival (OS) (HR = 0.75) compared with patients with DLBCL alone, but nearly identical EFS (HR = 1.00) and OS (HR = 0.84) compared with patients with GCB DLBCL alone. Patients with concurrent DLBCL and other indolent lymphomas had similar EFS (HR = 1.19) and OS (HR = 1.09) compared with patients with DLBCL alone. In conclusion, DLBCL patients with concurrent FL predominantly had the GCB subtype with outcomes similar to that of GCB DLBCL patients. DLBCL patients with concurrent other indolent lymphoma had similar outcomes compared with patients with DLBCL alone. These patients should not be summarily excluded from DLBCL clinical trials.

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.

Transformation of Follicular Lymphoma to a High-Grade B-Cell Lymphoma With MYC and BCL2 Translocations and Overlapping Features of Burkitt Lymphoma and Acute Lymphoblastic Leukemia: A Case Report and Literature Review

Most commonly, histologic transformation (HT) from follicular lymphoma (FL) manifests as a diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS). Less frequently, HT may result in a high-grade B-cell lymphoma (HGBL) with MYC and B-cell lymphoma protein 2 (BCL2) and/or BCL6 gene rearrangements, also known as “double-hit” or “triple-hit” lymphomas. In the 2016 revision of the World Health Organization (WHO) classification of lymphoid neoplasms, the category B-cell lymphoma, unclassifiable was eliminated due to its vague criteria and limiting diagnostic benefit. Instead, the WHO introduced the HGBL category, characterized by MYC and BCL2 and/or BCL6 rearrangements. Cases that present as an intermediate phenotype of DLBCL and Burkitt lymphoma (BL) will fall within this HGBL category. Very rarely, HT results in both the intermediate DLBCL and BL phenotypes and exhibits lymphoblastic features, in which case the WHO recommends that this morphologic appearance should be noted. In comparison with de novo patients with DLBCL, NOS, those with MYC and BCL2 and/or BCL6 gene rearrangements have a worse prognosis. A 63-year-old woman presented with left neck adenopathy. Laboratory assessments, including complete blood count, complete metabolic panel, serum lactate dehydrogenase, and β₂-microglobulin, were all normal. A whole-body computerized tomographic (CT) scan revealed diffuse adenopathy above and below the diaphragm. An excisional node biopsy showed grade 3A nodular FL. The Ki67 labeling index was 40% to 50%. A bone marrow biopsy showed a small focus of paratrabecular CD20+ lymphoid aggregates. She received 6 cycles of bendamustine (90 mg/m² on days +1 and +2) and rituximab (375 mg/m² on day +2), with each cycle delivered every 4 weeks. A follow-up CT scan at completion of therapy showed a partial response with resolution of axillary adenopathy and a dramatic shrinkage of the large retroperitoneal nodes. After 18 months, she had crampy abdominal pain in the absence of B symptoms. Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-d-glucose integrated with CT (18F-FDG PET/CT) scan showed widespread adenopathy, diffuse splenic involvement, and substantial marrow involvement. Biopsy of a 2.4-cm right axillary node (SUVmax of 16.1) showed involvement by grade 3A FL with a predominant nodular pattern of growth. A bone marrow biopsy once again showed only a small focus of FL. She received idelalisib (150 mg twice daily) and rituximab (375 mg/m², monthly) beginning May 2015. After 4 cycles, a repeat CT scan showed a complete radiographic response. Idelalisib was subsequently held while she received corticosteroids for immune-mediated colitis. A month later, she restarted idelalisib with a 50% dose reduction. After 2 weeks, she returned to clinic complaining of bilateral hip and low lumbar discomfort but no B symptoms. A restaging 18F-FDG PET/CT in January 2016 showed dramatic marrow uptake. A bone marrow aspirate showed sheets of tumor cells representing a spectrum from intermediate-sized cells with lymphoblastic features to very large atypical cells with multiple nucleoli. Two distinct histologies were present; one remained consistent with the patient’s known FL with a predominant nodular pattern and the other consistent with HT (the large atypical cells expressed PAX5, CD10, BCL2, and c-MYC and were negative for CD20, MPO, CD34, CD30, and BCL6). Focal areas showed faint, heterogeneous expression of terminal deoxynucleotidyl transferase best seen on the clot section. Ki67 proliferation index was high (4+/4). Fluorescence in situ hybridization analysis showed 2 populations with MYC amplification and/or rearrangement and no evidence of BCL6 rearrangement; a karyotype analysis showed a complex abnormal female karyotype with t(14;18) and multiple structural and numerical abnormalities. She started dose-adjusted rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin with concomitant prophylactic intrathecal methotrexate and cytarabine. She had but a short-lived response before dying in hospice from progressive lymphoma. Whether idelalisib could provide a microenvironment for selection of more aggressive clones needs to be addressed. Our patient’s clinical course is confounded by the incorporation of idelalisib while being further complicated by the complexity of HT and the mechanisms in which first-line chemotherapy regimens affect double-hit lymphoma.

Outpatient administration of BEAM conditioning prior to autologous stem cell transplantation for lymphoma is safe, feasible, and cost-effective

High-dose BEAM chemotherapy (BCNU, etoposide, Ara-C, and melphalan) followed by autologous hematopoietic stem cell transplantation is frequently used as consolidative therapy for patients with recurrent or refractory Hodgkin or non-Hodgkin lymphoma. The BEAM regimen has traditionally been administered over 6 days in the hospital, with patients remaining hospitalized until hematologic recovery and clinical stability. In an effort to reduce the length of hospitalization for these patients, our institution has transitioned from inpatient (IP) to outpatient (OP) administration of BEAM conditioning. Here, we report the results of an analysis of the feasibility, cost, complications, and outcomes for the initial group of patients who received OP BEAM compared to a prior cohort of patients who received IP BEAM. Patient and disease characteristics were comparable for the two cohorts, as were engraftment kinetics. Length of hospital stay was reduced by 6 days for the OP cohort (P < 0.001), resulting in a cost savings of more than $17,000 per patient. Fewer complications occurred in the OP cohort, including severe enteritis (P = 0.01), organ toxicities (P = 0.01), and infections (P = 0.04). Overall survival rate up to 3 years posttransplant was better for the OP cohort (P = 0.02), likely due to differences in posttransplant therapies. We conclude that OP administration of BEAM conditioning is safe and may offer significant advantages, including decreased length of hospitalization, reduced costs, decreased risks for severe toxicities and infectious complications, and likely improvement in patient satisfaction and quality of life.

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.

Outcomes of hematopoietic cell transplantation for diffuse large B cell lymphoma transformed from follicular lymphoma

There are limited data on the outcomes of autologous or allogeneic hematopoietic cell transplantation (HCT) in diffuse large B cell lymphoma transformed from follicular lymphoma. We analyzed transplantation outcomes in 141 subjects with biopsy-proven diffuse large B-cell lymphoma transformed from follicular lymphoma reported to the Center for International Blood and Marrow Transplant Research between 1990 and 2009. Two groups were identified: autologous HCT (auto-HCT; n = 108) and allogeneic HCT (allo-HCT; n = 33). Fewer auto-HCTs were done for transformed follicular lymphoma in 2003 to 2009, with a shift favoring allo-HCT. Auto-HCT was associated with a 1-year nonrelapse mortality (NRM) of 8% (95% confidence interval [CI], 4% to 14%), 5-year progression-free survival of 35% (95% CI, 26% to 45%), and 5-year overall survival of 50% (95% CI, 40% to 59%). In contrast, allo-HCT was associated with a 1-year NRM of 41% (95% CI, 23% to 58%), 5-year progression-free survival of 18% (95% CI, 6% to 35%), and 5-year overall survival of 22% (95% CI, 8% to 41%). Auto-HCT for transformed follicular lymphoma achieves sustained remission in a high proportion of subjects. The high NRM of allo-HCT offset any benefit that might be associated with this transplantation modality.

High dose chemotherapy with autologous stem cell transplant for patients with transformed B-cell non-Hodgkin lymphoma in the rituximab era

High dose chemotherapy with autologous stem cell transplant (HD-ASCT) is a recommended procedure for patients with transformed indolent B-cell lymphoma from the pre-rituximab era. In this retrospective single-center study, we present our experience with HD-ASCT in patients with histologically verified transformed indolent B-cell lymphoma in the rituximab era. Forty-two patients were included, of whom 28 with chemosensitive disease proceeded to HD-ASCT. Twenty patients (71%) achieved a complete response (CR) and five (18%) a partial response (PR) after HD-ASCT. With a median observation time of 49 months for the survivors, the median progression-free survival (PFS) and overall survival (OS) for patients with HD-ASCT were 39 months and 57 months, respectively. Patients who were rituximab-naive at transformation had a significantly better OS compared to patients previously treated with rituximab, both in the whole patient cohort and among the HD-ASCT-treated patients (p = 0.036 and p = 0.039, respectively). Furthermore, male sex influenced survival negatively, whereas time from diagnosis to transformation was positively associated with survival, both with borderline significance, in HD-ASCT-treated patients. In conclusion, HD-ASCT remains an effective treatment for transformed indolent lymphomas in the rituximab era.

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.

Autologous and Allogeneic Stem-Cell Transplantation for Transformed Follicular Lymphoma: A Report of the Canadian Blood and Marrow Transplant Group

Purpose

To determine whether autologous (auto) or allogeneic (allo) stem-cell transplantation (SCT) improves outcome in patients with transformed follicular lymphoma compared with rituximab-containing chemotherapy alone.

Patients and Methods

This was a multicenter cohort study of patients with follicular lymphoma and subsequent biopsy-proven aggressive histology transformation. Patient, treatment, and outcome data were collected from each transplantation center and combined for analysis. A separate control group was composed of patients with transformation treated with rituximab-containing chemotherapy but not SCT. The primary end point was overall survival (OS) after transformation.

Results

One hundred seventy-two patients were identified: 22 (13%) treated with alloSCT, 97 (56%) with autoSCT, and 53 (31%) with rituximab-containing chemotherapy. Five-year OS after transformation was 46% for patients treated with alloSCT, 65% with autoSCT, and 61% with rituximab-containing chemotherapy (P = .24). Five-year progression-free survival (PFS) after transformation was 46% for those treated with alloSCT, 55% with autoSCT, and 40% with rituximab-containing chemotherapy (P = .12). In multivariate analysis, patients treated with autoSCT had improved OS compared with those who received rituximab-containing chemotherapy (hazard ratio [HR], 0.13; 95% CI, 0.05 to 0.34; P < .001). On the other hand, there was no OS difference between those treated with alloSCT and rituximab-containing chemotherapy (HR, 0.44; 95% CI, 0.16 to 1.24; P = .12). OS and PFS after SCT were similar between those treated with autoSCT and alloSCT. Five-year transplantation-related mortality was 23% for those treated with alloSCT and 5% for autoSCT.

Conclusion

Patients undergoing autoSCT had better outcomes than those treated with rituximab-containing chemotherapy alone. AlloSCT did not improve outcome compared with rituximab-containing chemotherapy and was associated with clinically significant toxicity.

Update on the role of autologous hematopoietic stem cell transplantation in follicular lymphoma

Follicular lymphoma (FL) remains incurable despite advances in new strategies of treatment, including monoclonal antibodies (MoAb). Except for early stages, FL is characterized by responses to treatments and systematic relapses. The main objective in this disease is to achieve a better progression free survival (PFS) and to increase overall survival (OS), mainly in young patients. In order to improve the results of conventional chemotherapy, autologous stem cell transplant (ASCT) is a feasible treatment in these patients. In this moment, ASCT is not recommended as first line treatment, except for transformed FL, but is a good strategy as salvage therapy with an improved PFS and OS. New drugs have been introduced to enhance responses of ASCT, but nowadays they are not part of conventional conditioning regimen.