Transformed non-Hodgkin lymphoma in the rituximab era: analysis of the NCCN outcomes database

Outcomes of the transformation of follicular lymphoma to diffuse large B-cell lymphoma in the rituximab era: A population-based study

BACKGROUND

Histological transformation (HT) to diffuse large B-cell lymphoma (DLBCL) is a common complication of follicular lymphoma (FL) and is usually associated with a dismal outcome. However, the survival rate of these patients has improved over the last 20 years with the introduction of rituximab. This study aimed to access the outcome of transformation to DLBCL (t-DLBCL) from FL in a retrospective series that began after the widespread use of rituximab use. In addition, we also compared survival between t-DLBCL and primary DLBCL (p-DLBCL) in the same timeframe.

METHODS

We utilized the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with primary FL and patients with p-DLBCL between 2000 and 2020. Patients who had a subsequent diagnosis of DLBCL at least 2 months after FL diagnosis were identified as t-DLBCL.

RESULTS

Finally, we identified 50,332 FL and 95,933 p-DLBCL. With a median follow-up of 119 months, 1631 patients developed t-DLBCL. The median time from FL diagnosis to t-DLBCL was approximately 4 years. The post-transformation survival (PTS) rate at 5 years was 49.6%, with a median PTS of 56 months. Older age, advanced stage, and early transformation were associated with worse PTS. Furthermore, t-DLBCL receiving chemotherapy or combined modality as initial therapy before HT was also associated with worse PTS, while the result was inverse when taking the impact of initial management strategy at HT into account. Taking t-DLBCL and p-DLBCL as a whole, comparable survival was observed between p-DLBCL and t-DLBCL receiving radiation or watch-and-wait as initial therapy prior to HT.

CONCLUSION

The outcome of t-DLBCL in the rituximab era was better than historical series before the rituximab era. Due to the good prognosis, we did not recommend autologous stem cell transplantation for t-DLBCL receiving watch-and-wait or radiation as initial therapy before HT.

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.

Phase I study of novel SYK inhibitor TAK-659 (mivavotinib) in combination with R-CHOP for front-line treatment of high-risk diffuse large B-cell lymphoma

Background: TAK-659, a novel oral SYK inhibitor, has demonstrated efficacy in heavily pretreated diffuse large B-cell lymphoma (DLBCL). We report results of a phase I single-institution escalation study of front-line treatment with R-CHOP and TAK-659 in treatment-naïve high-risk DLBCL. Methods: Patients with high-risk DLBCL were treated with R-CHOP for 1 cycle, followed by combined R-CHOP and TAK-659 for an additional five cycles, with TAK-659 dosing escalated from 60 mg, to 80 mg, to 100 mg daily, based on a 3 + 3 design. The primary objective was to determine the safety and establish the maximum tolerated dose (MTD) of TAK-659 in this setting. Results: Twelve patients were enrolled. Dose level 3 (100 mg) was established as the MTD. Dose level 1 (60 mg) maintained a similar area under the curve (AUC) to the MTD. With a median follow-up of 21 months, 92% of patients achieved complete response (CR). The most common treatment-emergent adverse events were lymphopenia (100%), infection (50%, n = 3 opportunistic), aspartate aminotransferase elevation (100%), and alanine aminotransferase elevation (83%). Conclusion: A TAK-659 dose of 60 mg was well tolerated, did not require dose modifications, and maintained a similar AUC to the MTD. The combination of R-CHOP and TAK-659 in patients with newly diagnosed high-risk DLBCL produces promising CR rates.

Risk Factors for and Outcomes of Follicular Lymphoma Histological Transformation at First Progression in the GALLIUM Study

BACKGROUND

Although advanced‑stage follicular lymphoma (FL) is considered incurable, survival has improved with the introduction of the anti-CD20 antibodies, rituximab (R) and obinutuzumab (G). However, FL can undergo histological transformation (HT) to a more aggressive disease, and a validated model for predicting HT risk is not yet available.

PATIENTS AND METHODS

We assessed HT incidence, risk factors and outcomes in the phase III, GALLIUM study evaluating R- or G-chemotherapy in patients with previously untreated, advanced-stage FL (ClinicalTrials.gov NCT01332968). HT rates were assessed by repeat tumour biopsy at disease progression or relapse, at the investigator's discretion.

RESULTS

Of 1202 patients enrolled, 315 (26.2%) experienced progressive disease; 46 (14.6%) had a biopsy at first progression, 40 of whom had biopsy-confirmed HT. HT risk factors were male sex (subdistribution hazard ratio [sHR], 2.21; 95% confidence interval [CI], 1.16-4.20), elevated baseline serum lactate dehydrogenase (sHR, 3.97; 95% CI, 2.03-7.76), and elevated baseline serum β₂-microglobulin (sHR, 1.96; 95% CI, 1.02-3.79). Patients with HT at first progression had poorer post-progression survival than those with relapsed FL (2-year rate: 55.9% vs. 83.1%). Relapse with HT occurred earlier than FL relapse (median time from randomisation: 0.8 vs. 2.3 years).

CONCLUSION

HT was a low-frequency event associated with poor survival outcomes in the GALLIUM study. Male sex and elevated baseline levels of serum LDH and B2M were significant risk factors for HT. Further research is required to develop validated prognostic indices for HT risk and guide treatment decisions.

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.

Screening of Adverse Prognostic Factors and Construction of Prognostic Index in Previously Untreated Concurrent Follicular Lymphoma and Diffuse Large B-Cell Lymphoma

Objective

Concurrent follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) (defined as FL/DLBCL) have been considered an important pathological feature in cell lymphoma. However, clinicopathological information and prognostic factors in these cases are scarce. The aim of this study was to construct a prediction index to compare with traditional prognostic models.

Methods

Retrospectively enrolled, previously untreated FL/DLBCL (n = 121) patients, as well as those with pure FL 1-3a (n = 471), were assessed. De novo DLBCL (n = 529) were used as controls. Kaplan-Meier curves were plotted to compare the outcomes among the three groups. Multivariate analysis identified risk factors associated with overall survival (OS) in FL/DLBCL patients. A clinicopathological prognosis index (CPPI) was developed to predict OS based on the Cox proportional hazards model.

Results

The outcomes of FL/DLBCL patients were intermediate between pure FL 1-3a and de novo DLBCL patients, with a 5-year PFS of 70%, 59%, and 48% (P < 0.05) and 5-year OS of 80%, 70% and 60% (P < 0.05), respectively. Cox regression analysis showed that the prognostic factors of OS for FL/DLBCL patients included FL grade, cell of origin, and Ann Arbor stage. A nomogram and clinicopathological prognostic index (CPPI) were developed to predict the OS for FL/DLBCL patients based on these factors. The area under the curve (AUC) of the CPPI for 3- and 5-year OS prediction was 0.782 and 0.860, respectively. This was superior to that of the International Prognostic Index (IPI), Follicular Lymphoma International Prognostic Index (FLIPI), and FLIPI2 in the 0.540-0.819 (P < 0.01) range.

Conclusions

A valid OS estimation in FL/DLBCL patients, using the recommended CPPI, may be useful in routine clinical practice.

Outcomes of Autologous Hematopoietic Cell Transplantation in Older Patients with Diffuse Large B Cell Lymphoma

Data for outcomes after autologous hematopoietic cell transplantation (auto-HCT) in diffuse large B-cell lymphoma (DLBCL) patients ≥70 years are limited. Auto-HCT is feasible in older DLBCL patients. Using the Center for International Blood and Marrow Transplant Research database, we compared outcomes of auto-HCT in DLBCL patients aged 60 to 69 years (n = 363) versus ≥70 years (n = 103) between 2008 and 2019. Non-relapse mortality (NRM), relapse/progression (REL), progression-free survival (PFS), and overall survival (OS) were modeled using Cox proportional hazards models. All patients received BEAM conditioning (carmustine, etoposide, cytosine arabinoside and melphalan). On univariate analysis, in the 60 to 69 years versus ≥70 years cohorts, 100-day NRM was 3% versus 4%, 5-year REL was 47% versus 45%, 5-year PFS 40% versus 38% and 5-year OS 55% versus 41%, respectively. On multivariate analysis, patients ≥70 had no significant difference in NRM (hazard ratio [HR] 1.43, 95% confidence interval [CI] 0.85-2.39), REL (HR 1.11, 95% CI 0.79-1.56), PFS (HR 1.23, 95% CI 0.92-1.63) compared to patients 60 to 69 years. Patients ≥70 years had a higher mortality (HR 1.39, 95% CI 1.05-1.85, p=0.02), likely because of inferior post-relapse OS in this cohort (HR 1.82, 95% CI 1.27-2.61, P = .001). DLBCL was the major cause of death in both cohorts (62% versus 59%). Older patients should not be denied auto-HCT solely on the basis of chronological age.

Lenalidomide in combination with R-CHOP produces high response rates and progression-free survival in new, untreated diffuse large B-cell lymphoma transformed from follicular lymphoma: results from the Phase 2 MC078E study

Diffuse large B-cell lymphoma (DLBCL), either concurrent with or transformed from follicular lymphoma (FL) is often excluded from clinical trials. Lenalidomide has response rates of 45% in relapsed transformed DLBCL. Herein we present an analysis of MC078E, a phase II clinical trial testing lenalidomide plus R-CHOP (R2CHOP) for patients with untreated transformed/concurrent DLBCL (NCT00670358). Adult patients with transformed or concurrent DLBCL were included. Patients received six cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) with lenalidomide 25 mg days 1-10 of each cycle. The primary outcome was progression-free survival (PFS) at 24 months. Secondary outcomes were response rates, event-free survival (EFS), and overall survival (OS). Thirty-nine patients were accrued from August 5, 2013 to July 28, 2020 and 33 were eligible by central pathology review. The median age was 64 (24-80) years, 18 (54%) were male, 25 (76%) were concurrent and 8 (24%) were transformed DLBCL. The PFS, EFS, and OS rates at 24 months were 84.4% (CI₉₅: 67.2-94.7%), 84.5% (CI₉₅: 72.9-98%), and 97.0% (CI₉₅: 91.3-100%), respectively. R2CHOP is effective in concurrent and transformed DLBCL. The study supports the inclusion of anthracycline-naive transformed and concurrent DLBCL in future clinical trials of novel immunomodulatory analogues.

Rituximab Maintenance Versus Observation After Immunochemotherapy (R-CHOP, R-MCP, and R-FCM) in Untreated Follicular Lymphoma Patients: A Randomized Trial of the Ostdeutsche Studiengruppe Hämatologie und Onkologie and the German Low-Grade Lymphoma Study Group

The German study groups, the German Low-Grade Lymphoma Study Group (GLSG) and Ostdeutsche Studiengruppe Hämatologie und Onkologie (OSHO), initiated in 2007 a double randomized trial to investigate efficacy and safety of rituximab maintenance versus observation in remission after randomly assigned induction treatment in the first-line follicular lymphoma. Previously untreated patients with stage II–IV follicular lymphoma in need of therapy were randomized to receive 6 cycles of R-CHOP, R-MCP, or R-FCM. Responding patients were subsequently randomized to 2 years rituximab maintenance or observation, stratified by type of immunochemotherapy, quality of remission, and Follicular Lymphoma International Prognostic Index (FLIPI). Recruitment was stopped in 2011 after the PRIMA results had been published. Median age of the 206 recruited patients was 66 years (range, 24–86), and (FLIPI) was low in 13%, intermediate in 28%, and high in 60%. High and comparable overall response rates were observed after R-CHOP (88%), R-MCP (89%), and R-FCM (91%). Rituximab maintenance substantially prolonged progression-free survival (PFS) in comparison to observation in remission (hazard ratio 0.39, P = 0.0064). In the rituximab maintenance group, the 3-year PFS was 89% compared with 69% in the observation group. No differences in overall survival were observed for maintenance vs. observation (hazard ratio 1.04, 95% confidence interval 0.32–3.43, P = 0.95). In this randomized trial, 2 years of rituximab maintenance was associated with significantly prolonged PFS in comparison to observation after response to first-line immunochemotherapy in follicular lymphoma. Our data represent an independent confirmation of the PRIMA trial results.

(Clinical Trial EudraCT Number: 2005-005473-29, 2006-09-26)

Rituximab maintenance improves outcomes of transformed diffuse large B-cell lymphoma: a retrospective study of 519 cases with de novo diffuse large B-cell lymphoma and 62 cases with concurrent diffuse large B-cell lymphoma and follicular lymphoma

Although outcomes of transformed diffuse large B-cell lymphoma (DLBCL) from follicular lymphoma (FL) were improved using rituximab-combined immunochemotherapy, the efficacy of subsequent rituximab maintenance (RM) remains unclear. We retrospectively analyzed the prognoses of 519 patients with de novo DLBCL and 62 patients with concurrent DLBCL and FL (concurrent-DLBCL/FL). Progression-free survival (PFS) was shorter in patients with concurrent-DLBCL/FL than in de novo DLBCL (p=.030). Twenty-four patients with concurrent-DLBCL/FL received RM after induction therapy, and they achieved better OS and PFS (p=.010 and p<.001, respectively) with lower risk of relapse (p<.001) than the non-RM group. Moreover, concurrent-DLBCL/FL showed better subsequent OS and PFS after recurrence than de novo DLBCL (p=.0083 and p=.0044, respectively). Our study indicates that in the face of a high relapse rate, concurrent-DLBCL/FL is manageable and benefits from RM.

Histologic Transformation in an Untreated Waldenstrom's Macroglobulinemia After 14 Years: Case Report and Review of the Literature

Waldenstrom's macroglobulinemia (WM) is an indolent B-cell non-Hodgkin lymphoma characterized by lymphoplasmacytic histology in the bone marrow with monoclonal IgM. Median survival can be in excess of 10 years. The 5-year cumulative incidence of death is low at about 10%. One-third of all-cause specific mortality is due to the lymphoma for which histologic transformation (HT) is rare. Here we present a case of a 60-year-old man with longstanding untreated WM, presenting with minimally symptomatic transformation to diffuse large B-cell lymphoma (DLBCL), with an accompanying review of the literature. Transformed WM, diagnosed greater than 5 years, has a reported survival period of 8 - 9 months. This case highlights that after a decade of continued stability in WM, not requiring treatment, an acute change in laboratory data with minimally progressive IgM levels, in the absence of B symptoms and clinical findings, may be the harbinger of transformation and at the time of diagnosis can have a rapidly deteriorating clinical course. In this case, the tripling of the lactate dehydrogenase (LDH) as the primary drastic change demonstrates the importance of the rapid increase in LDH as a singly reliable marker for HT. Late transformation has been borne out as a negative variable as the generally indolent course of WM is curtailed with the poor outcome in HT. Although MYD88 wildtype is a possible predictive factor for transformation, it is unclear if late transformation is clonally or non-clonally related and further molecular investigation is needed.

Systematic review of the potential of MicroRNAs in the management of patients with follicular lymphoma

Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma and usually presents as an indolent disease. However, some patients present poor outcomes, and FL can transform into more aggressive lymphomas, such as Diffuse Large B cell lymphoma (DLBCL). MicroRNAs (miRNA) are small RNA molecules that participate in posttranscriptional regulation of gene expression, that are emerging biomarkers in cancer. In this systematic review, we included studies evaluating miRNA expression in tumor tissue as diagnosis, transformation or prognosis biomarkers in FL. We identified several miRNAs, which could be diagnostic biomarkers in FL: miR-155-5p and miR-9-3p as miRNAs of potential utility for diagnosis of FL, and miR-150 and miR-17-92 cluster for differential diagnosis between FL and DLBCL. Prognosis and transformation prediction have not been studied in enough depth to draw solid conclusions. Further research is needed to exploit the potential of this field.

Transformed lymphoma: what should I do now?

Although the majority of indolent lymphomas (focusing on follicular lymphoma [FL]) have a prolonged waxing and waning course, a portion of patients experience histologic transformation (HT) to either diffuse large B-cell lymphoma or a higher-grade morphology, often with acquisition of MYC and BCL2 and/or BCL6 rearrangements (high-grade B-cell lymphoma-double-hit lymphoma/triple-hit lymphoma). The overall incidence of HT and transformed follicular lymphoma (tFL) may be declining, but outcomes remain inferior to those in simple indolent lymphoma progression. Recent data suggest that the majority of HT cases occur in higher-risk patients with FL, and they occur early after initial chemoimmunotherapy, comprising the majority of patients with progression of disease within 24 months. This latter point emphasizes the need for a sufficient biopsy at relapse in FL. Treatment options depend on the prior therapy for the indolent component as well as the histology at relapse, but they generally follow several principles discussed in this article. Anthracycline-naïve patients have the best outcomes if there is HT, and responses to R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) are similar to those of patients with de novo diffuse large B-cell lymphoma. Patients with anthracycline exposure prior to transformation have the best outcomes with salvage chemotherapy and a consolidative autologous stem cell transplant. However, a major challenge is the management of patients with tFL who experience relapse early after bendamustine-based treatment, in whom the role of consolidative transplant after anthracycline-based treatment is unclear. In the past several years, cellular therapy has emerged as an important tool for some but not all patients with tFL. This review focuses on the nuances of managing tFL.

The role of local radiotherapy following rituximab-containing chemotherapy in patients with transformed indolent B-cell lymphoma

Objectives

This study aimed to evaluate the outcomes of local radiotherapy (LRT) in patients with histologic transformation (HT) following rituximab‐containing chemotherapy.

Methods

We retrospectively analysed 92 patients with biopsy‐confirmed HT undergoing rituximab‐containing chemotherapy at our institution between 2003 and 2015.

Results

Of the 36 patients with limited‐stage disease at diagnosis of HT, 29 (78%) received LRT. The estimated 5‐year progression‐free survival (PFS) rate was significantly better in patients who underwent LRT than in those who did not (93% and 42%, respectively; P < 0.05). Multivariate analyses employing age, sex, performance status, LRT and treatment response demonstrated that LRT was an independent prognostic factor for PFS (hazard ratio [HR]: 11.8; 95% confidence interval [CI]: 1.28‐108.1; P < 0.05). Of the 32 patients who underwent LRT for HT lesion treatment, 31 (97%) did not show disease progression within radiation fields; among them, 27 patients (84%) survived without disease progression during the follow‐up period. One patient developed hypothyroidism due to LRT; the others had no acute or late‐onset complications of LRT.

Conclusions

Our data support the recommendation of LRT for HT lesion treatment following rituximab‐containing chemotherapy in select patients with localised HT, as a rational treatment approach with potentially limited toxicity.

Transformation Scoring System (TSS): A new assessment index for clinical transformation of follicular lymphoma

Although histologic analysis is the gold standard for diagnosing follicular lymphoma (FL) transformation, many patients are diagnosed with transformation by clinical factors as biopsy specimens often cannot be obtained. Despite the frequency of clinical diagnosis, no clinical assessment tool has yet been established for FL transformation in the rituximab era. We derived and validated a transformation scoring system (TSS) based on retrospective analyses of 126 patients with biopsy‐proven FL and histologic transformation (HT) at two hospitals of the National Cancer Center of Japan. In the derivation set (76 patients), the detailed analyses of the clinical characteristics at disease progression showed that lactate dehydrogenase (LDH) elevation, focal lymph nodal (LN) enlargement, hemoglobin <12 g/dl, and poor performance status (PS) (2‐4) were associated with HT. The weights of these variables were decided based on the regression coefficients. Next, we constructed a TSS encompassing the above four factors: LDH, (> upper limit of normal [ULN], ≤ULN ×2) (1 point), (≥ULN ×2) (2 points); focal LN enlargement, (≥3 cm, <7 cm) (1 point), (≥7 cm) (2 points); hemoglobin <12 g/dl (1 point); poor PS (2 points). We identified a high positive predictive value (PPV) (96.4%) and negative predictive value (NPV) (85.4%) for diagnosing HT when a cutoff score of 2 was selected for our TSS. In an external validation set (50 patients), the probability of HT was high with scores ≥2 (PPV, 93.3%; NPV, 82.9%). We developed a TSS that offers a simple, yet, valuable tool, for diagnosing HT, especially in patients who cannot undergo biopsy.

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.

Excellent outcomes of transformed lymphomas in the rituximab era without autologous stem cell transplantation: an Australian, single-centre experience

BACKGROUND

Histologic transformation (HT) is an important event with adverse prognosis in the natural history of indolent lymphomas. There is minimal data on HT in the Australian setting.

AIM

To characterise patients with biopsy-proven HT and their outcomes identified at a tertiary Australian Hospital.

METHODS

All patients with biopsy-proven HT during a 15-year period (2002-2017) were included. Clinico-pathological data were systematically collected from review of patient records. Survival estimates were assessed by the Kaplan-Meier method and compared using the log-rank test. Associations between variables and clinical outcomes were evaluated using Cox's proportional hazards model.

RESULTS

A cohort of 45 patients was identified with a median age of 66 years and the majority (59%) having high-risk disease (Revised-International Prognostic Index score ≥ 3). R-CHOP induction was used in 69% with an overall response rate of 82% (complete response (CR), 75%). 61% of these induction-responders received consolidation, with autologous stem cell transplant (ASCT) performed in only 17% and rituximab maintenance given to 31%. With a median follow-up of 47 months (range: 4-136), the 5-year overall survival (OS) was 69% (95% CI: 52%, 81%). Chemotherapy-naivety at HT was associated with a superior rate of CR (84% vs. 54%, p = 0.057) and 5-year OS (82% vs. 46%, p = 0.012). Rituximab maintenance was associated with a durable progression-free survival in induction-responders.

CONCLUSIONS

Excellent OS was observed in this modern cohort of patients treated with rituximab-containing induction and low rate of consolidation by ASCT, particularly in those who were chemotherapy-naïve at HT. This article is protected by copyright. All rights reserved.

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).

Treatment of Histologic Transformation

Histologic transformation from follicular lymphoma to aggressive lymphoma historically had a poor prognosis. Routine use of anti-CD20 antibody rituximab has changed the landscape of follicular lymphoma (FL) such that outcomes are improved in select patients, similar to de-novo diffuse large B-cell lymphoma. Several biological and clinical biomarkers can predict risk of transformation, and ongoing research is improving understanding of the biology surrounding the transformation process. This review provides an overview of risk factors, prognosis, and treatment of histologic transformation of FL.

Survival outcomes of diffuse large B-cell lymphoma by association with concurrent or antecedent follicular lymphoma and double hit status

Diffuse large B-cell lymphoma (DLBCL) transformed from follicular lymphoma (FL) (tDLBCL) has been traditionally associated with an aggressive course, but more recent studies have shown longer survivals. The clinical significance of concurrent FL at the time of diagnosis of DLBCL (cDLBCL/FL) is less clear. We compared outcomes of tDLBCL, cDLBCL/FL, and de novo DLBCL (dDLBCL) and then evaluated the impact of double hit (DH) rearrangements (MYC with BCL2 and/or BCL6) in these subgroups' outcomes. The progression free survival (PFS) and overall survival (OS) were not significantly different among the three groups (dDLBCL, tDLBCL, and cDLBCL/FL). The effect of DH on survival was then analyzed in two subgroups: (1) dDLBCL and (2) tDLBCL + cDLBCL/FL. PFS and OS were significantly shorter in lymphomas with DH in each of these two subgroups. We conclude that DH status drives outcomes in all DLBCLs, regardless of their transformation status.

Up-front rituximab maintenance improves outcome in patients with follicular lymphoma: a collaborative Nordic study

The introduction of the anti-CD20 antibody rituximab in combination with chemotherapy (R-chemo) has improved the prognosis of patients with follicular lymphoma (FL). During the last decade, the addition of a maintenance treatment with rituximab (MR) after R-chemo has been tested with the hope of further improving the outcome of these patients. Using 2 independent population-based cohorts, we investigated the effect of up-front MR on time related end points as well as the risk of histological transformation (HT). FL patients were included if they: (1) completed first-line induction treatment with R-chemo, (2) were alive after induction treatment and eligible for MR, and (3) had no evidence of HT at this time point. The training cohort consisted of 733 Danish patients of whom 364 were consolidated with MR; 369 were not. Patients receiving MR more often had advanced clinical stage (90% vs 78%), high Follicular Lymphoma International Prognostic Index (FLIPI) score (64% vs 55%), and bone marrow infiltration (49% vs 40%). Those consolidated with MR had an improved 5-year overall survival (OS; 89% vs 81%; P = .001) and progression-free survival (PFS; 72% vs 60%; P < .001). In the training cohort, MR was associated with a reduction of HT risk (P = .049). Analyses of an independent validation cohort of 190 Finnish patients confirmed the favorable impact of MR on 5-year OS (89% vs 81%; P = .046) and PFS (70% vs 57%; P = .005) but did not find a reduced risk of HT. The present population-based data suggest that the outcome of patients with FL has improved after consolidation of R-chemo with MR.

Transformed follicular lymphoma in the rituximab era: A report from the Spanish Lymphoma Oncology Group

Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma (NHL) subtype. The histological transformation (HT) of FL is an event considered frequent in the natural history of this tumor. We studied the transformation rates, predictive factors, and treatment characteristics that may impact in the survival of patients with FL and HT. A total of 1074 patients diagnosed with FL were prospectively enrolled from 1990 to 2016 in a Spanish registry. Sixty-four HTs were recorded based on clinical criteria (55%) or histological confirmation (45%). The cumulative incidence rate of transformation at 5 years is 7.3%. The 5-year overall survival (OS) without HT was 85% (95% confidence interval [CI], 70%-90%) vs 66% (95% CI, 51%-76%; P = 0.0012) with HT. Factors associated with HT were elevated lactate dehydrogenase (LDH) (odds ratio [OR] 1.83), intermediate-high Follicular lymphoma international prognostic index (FLIPI) (OR 2.16-OR 3.21), B symptoms (OR 2.46), or Eastern Cooperative Oncology Group (ECOG) 1 (OR 2.35). Treatment options related to HT were "watch and wait" or no rituximab or anthracyclines initially. A 5-year OS for patients treated with chemotherapy before HT was 55% (95% CI, 38%-69%) versus 81% (95% CI, 53%-93%; P = 0.009) for those who had not received it. The HT rate has decreased after the introduction of rituximab, as has been previously described. The timing of this treatment had an impact on the survival of these patients.

The Karolinska experience of autologous stem-cell transplantation for lymphoma: a population-based study of all 433 patients 1994-2016

Background

Autologous stem-cell transplantation (ASCT) is a common treatment for lymphoma but it has some mortality.

Methods

All 433 lymphoma patients who underwent ASCT for lymphoma at Karolinska Huddinge 1994–2016 were investigated, including CD34⁺ cell amounts, medications, infectious and other complications, intensive care, longitudinal laboratory values, and secondary myeloid neoplasia.

Results

The 100-day non-relapse and overall mortalities were 5.6% and 7.2%. Stem-cell harvests < 5 million CD34⁺ cells/kg correlated with inferior 100-day and long-term survival. Prior to conditioning (93% BEAM), elevated (both 3–9 and ≥ 10 mg/L) C-reactive protein (CRP) and creatinine, and low albumin (but not higher age) predicted inferior higher 100-day survival. Intravenous antibiotics were given to 97% (22% positive blood cultures) and parenteral nutrition to 89%. After 1 year, 86% had normalized hemoglobin. The 5-year risk for secondary myeloid neoplasia was 4.1%, associated with smaller harvests.

Conclusions

Before starting conditioning, patients should have preferably harvested ≥ 5 million CD34⁺ cells/kg and normal CRP, albumin, and creatinine. It appears safe to transplant patients ≥ 66 years.

Electronic supplementary material

The online version of this article (10.1186/s40164-019-0131-3) contains supplementary material, which is available to authorized users.

An update in treating transformed lymphoma

Indolent lymphomas typically have a prolonged course and favorable prognosis. Recent data support survival times that can reach several decades, even if periodic treatment is needed to manage symptoms or stabilize disease. However, all indolent lymphomas have the potential to undergo transformation to an aggressive phenotype, clinically characterized by a rapid progression of adenopathy, new-onset constitutional symptoms, or laboratory abnormalities, and the immediate need for therapeutic intervention. The most common scenario is transformation of follicular lymphoma to either diffuse large B-cell lymphoma or high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 translocations; however, other indolent subtypes such as marginal zone lymphoma, lymphoplasmacytic lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia, or even nodular lymphocyte predominant Hodgkin lymphoma, can undergo similar histologic transformation. The prognosis of transformed lymphomas has historically been quite poor, but there is ample evidence this is changing in the rituximab era. This article will provide a review of transformed lymphomas with an emphasis on treatment and the nuances of diagnosis and clinical management. Unless otherwise specified, all discussion in this review pertains to transformed follicular lymphoma which is the more common scenario and the subtype with the most robust data. In many cases, this information can be extrapolated and applied to other indolent histologies (i.e. transformed marginal zone lymphoma); however, several other clinical scenarios, such as Richter's transformation and "double hit" transformations, warrant a distinct discussion and will be reviewed separately.

Coccidioidomycosis, immunoglobulin deficiency: safety challenges with CAR T cells therapy for relapsed lymphoma

Treatment of patients with relapsed or refractory lymphoma may require allogenic hematopoietic stem cell transplant (HSCT), but treatment of post-transplant relapse disease remains very challenging. Donor lymphocyte infusion and blinatumomab have been used with limited success for the treatment of relapse. Initial data on donor-derived CAR T cells has shown this modality to be safe and highly effective in various hematological malignancies. We present a case of a patient with highly refractory, transformed follicular lymphoma who failed both autologous and allogenic HSCT. Patient achieved long-lasting complete remission with the use of donor origin CD19 CAR T-cell therapy, without any evidence of graft-versus-host disease flare. Our patient later developed disseminated coccidioidomycosis and persistent hypogammaglobulinemia. Immunotherapy using CD19 CAR T cells can be a highly effective salvage modality, especially in cases of focal lymphoma relapse. Long-term immunosuppression secondary to B cell lymphopenia, hypogammaglobulinemia, immunoglobulin subclass deficiency, fungal infections and other infectious complications need to be monitored and promptly treated as indicated.

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.

The incidence of biopsy-proven transformation in follicular lymphoma in the rituximab era. A retrospective analysis from the Czech Lymphoma Study Group (CLSG) database

The aim of this study is to assess the incidence, risk factors, and outcome of biopsy-proven transformation in follicular lymphoma (FL) patients in the rituximab era. Transformation was analyzed in 1233 patients with initially diagnosed FL grades 1-3A, identified between 2002 and 2012 in the prospectively maintained Czech Lymphoma Study Group database. Only patients with histologically proven transformation (HT) were included. HT occurred in 58 cases at a median of 3.0 years from the initial FL diagnosis; the HT rate was 4% at 5 years. Transformation occurred most frequently at the first relapse (84% patients). Median OS from the HT was 2.5 years (95% CI 0.4-4.6) and 6-year OS with HT was shorter compared to all FLs (60 vs. 83.9%; 95% CI). A bulky tumor (≥ 10 cm), increased lactate dehydrogenase, age ≥ 60 years, and International Prognostic Index (intermediate/high risk), but not Follicular Lymphoma International Prognostic Index, were associated with transformation (p < 0.05). In the first line, 70% of patients received rituximab (including 36% rituximab maintenance), 57% CHOP-like regimens, and 2.6% of patients were treated with fludarabine-based therapy, whereas 11% of patients were watched only. The patients treated with R-CHOP in the first line (n = 591) showed the transformation rate at 5 years of 4.23% (95% CI 2.52-5.93); subsequent rituximab maintenance (n = 276) vs. observation (n = 153) was associated with a lower transformation rate (p.033; HR 3.29; CI 1.10-9.82). The transformation rate seems to be lower than in previous series, which may be influenced by broad use of rituximab, but prognosis of HT developed during therapy continues to be poor.

Transformed follicular lymphoma

Follicular Lymphoma (FL) is the second most common type of non-Hodgkin lymphoma and is considered to be the prototype of indolent lymphomas. Histologic transformation into an aggressive lymphoma, which is expected to occur at a rate of 2 to 3% each year, is associated with rapid progression, treatment resistance, and poor prognosis. Recent modifications to the physiopathologic mechanism of transformed follicular lymphoma (t-FL) have been proposed, including genetic and epigenetic mechanisms as well as a role for the microenvironment. Although t-FL is considered a devastating complication, as it is associated with treatment-refractory disease and a dismal outcome, recent data in the rituximab era have suggested that not only is the prognosis less severe than reported in the previous literature but the risk of transformation is also lower. Thus, this study aimed to review the most recent research on t-FL in an attempt to better understand the clinical meaning of transformation from FL to diffuse large B cell lymphoma (DLBCL) and the impact of current treatment strategies on the curability of this intriguing subentity of lymphoma.

Risk of, and survival following, histological transformation in follicular lymphoma in the rituximab era. A retrospective multicentre study by the Spanish GELTAMO group

The diagnostic criteria for follicular lymphoma (FL) transformation vary among the largest series, which commonly exclude histologically-documented transformation (HT) mandatorily. The aims of this retrospective observational multicentre study by the Spanish Grupo Español de Linfoma y Transplante Autólogo de Médula Ósea, which recruited 1734 patients (800 males/934 females; median age 59 years), diagnosed with FL grades 1-3A, were, (i) the cumulative incidence of HT (CI-HT); (ii) risk factors associated with HT; and (iii) the role of treatment and response on survival following transformation (SFT). With a median follow-up of 6·2 years, 106 patients developed HT. Ten-year CI-HT was 8%. Considering these 106 patients who developed HT, median time to transformation was 2·5 years. High-risk FL International Prognostic Index [Hazard ratio (HR) 2·6, 95% confidence interval (CI): 1·5-4·5] and non-response to first-line therapy (HR 2·9, 95% CI: 1·3-6·8) were associated with HT. Seventy out of the 106 patients died (5-year SFT, 26%). Response to HT first-line therapy (HR 5·3, 95% CI: 2·4-12·0), autologous stem cell transplantation (HR 3·9, 95% CI: 1·5-10·1), and revised International Prognostic Index (HR 2·2, 95% CI: 1·1-4·2) were significantly associated with SFT. Response to treatment and HT were the variables most significantly associated with survival in the rituximab era. Better therapies are needed to improve response. Inclusion of HT in clinical trials with new agents is mandatory.

How I treat double-hit lymphoma

These lymphomas, which occur in <10% of cases of diffuse large B-cell lymphoma, have been referred to as double-hit lymphomas (or triple-hit lymphomas if all 3 rearrangements are present). It is important to differentiate these lymphomas from the larger group of double-expressor lymphomas, which have increased expression of MYC and BCL-2 and/or BCL-6 by immunohistochemistry, by using variable cutoff percentages to define positivity. Patients with double-hit lymphomas have a poor prognosis when treated with standard chemoimmunotherapy and have increased risk of central nervous system involvement and progression. Double-hit lymphomas may arise as a consequence of the transformation of the underlying indolent lymphoma. There are no published prospective trials in double-hit lymphoma, however retrospective studies strongly suggest that aggressive induction regimens may confer a superior outcome. In this article, I review my approach to the evaluation and treatment of double-hit lymphoma, with an eye toward future clinical trials incorporating rational targeted agents into the therapeutic armamentarium.

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.

Outcome Comparison of Allogeneic versus Autologous Stem Cell Transplantation in Transformed Low-Grade Lymphoid Malignancies: A Systematic Review and Pooled Analysis of Comparative Studies

BACKGROUND

Some patients with low-grade lymphoid malignancies develop transformed disease, requiring stem cell transplantation (SCT). SCT outcomes in transformed low-grade lymphoid malignancies may differ from those of nontransformed disease or other aggressive non-Hodgkin lymphomas. We conducted a pooled analysis of the clinical outcomes of allogeneic versus high-dose therapy (HDT) with autologous SCT in adult patients with transformed low-grade lymphoid malignancies.

METHODS

A PubMed, EMBASE, and Cochrane search yielded 4 comparative studies reporting allogeneic versus HDT with autologous SCT outcomes in adults (age ≥18) with transformed low-grade lymphoid malignancies, including follicular, chronic/small lymphocytic, and marginal zone lymphoma. Risk ratio (RR) and 95% CI were calculated using random-effects models.

RESULTS

Rates for overall survival (OS) were 51.0 versus 69.5% (RR = 1.55, 95% CI 1.19-2.02, p = 0.001), rates of relapse were 37.3 versus 35.3% (RR = 1.04, 95% CI 0.70-1.55, p = 0.84), and rates of transplant-related mortality (TRM) were 33.3 versus 7.2% (RR = 4.52, 95% CI 2.75-7.43, p < 0.00001) for allogeneic versus autologous SCT. Previous rituximab treatment, reduced intensity conditioning regimen prior to SCT, or original pathology had no prognostic impact.

CONCLUSION

HDT followed by autologous SCT was associated with lower TRM and a better OS, but there was no difference in relapse versus allogeneic SCT. Autologous SCT may be the better therapeutic option, considering the second chance of allogeneic SCT in the case of relapse.

Early event status informs subsequent outcome in newly diagnosed follicular lymphoma

Recent advances in follicular lymphoma (FL) have resulted in prolongation of overall survival (OS). Here we assessed if early events as defined by event-free survival (EFS) at 12 and 24 months from diagnosis (EFS12/EFS24) can inform subsequent OS in FL. 920 newly diagnosed grade 1-3A FL patients enrolled on the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) from 2002-2012 were initially evaluated. EFS was defined as time from diagnosis to progression, relapse, re-treatment, or death due to any cause. OS was compared to age-and-sex-matched survival in the general US population using standardized mortality ratios (SMR) and 95% confidence intervals (CI). We used a cohort of 412 FL patients from two Lyon, France hospital registries for independent replication. Patients who failed to achieve EFS12 had poor subsequent OS (MER SMR = 3.72, 95%CI: 2.78-4.88; Lyon SMR = 8.74, 95%CI: 5.41-13.36). Conversely, patients achieving EFS12 had no added mortality beyond the background population (MER SMR = 0.73, 95%CI: 0.56-0.94, Lyon SMR = 1.02, 95%CI: 0.58-1.65). Patients with early events after immunochemotherapy had especially poor outcomes (EFS12 failure: MER SMR = 17.63, 95%CI:11.97-25.02, Lyon SMR = 19.10, 95%CI:9.86-33.36; EFS24 failure: MER SMR = 13.02, 95%CI:9.31-17.74, Lyon SMR = 7.22, 95%CI:4.13-11.74). In a combined dataset of all patients from both cohorts, baseline FLIPI was no longer informative in EFS12 achievers. Reassessment of patient status at 12 months from diagnosis in follicular lymphoma patients, or at 24 months in patients treated with immunochemotherapy, is a strong predictor of subsequent overall survival in FL. Early event status provides a simple, clinically relevant endpoint for studies assessing outcome in FL. Am. J. Hematol. 91:1096-1101, 2016. © 2016 Wiley Periodicals, Inc.

Histological transformation to diffuse large B-cell lymphoma in patients with Waldenström macroglobulinemia

Histological transformation to diffuse large B-cell lymphoma (DLBCL) rarely occurs in patients with Waldenström Macroglobulinemia (WM). We identified 20 patients out of a cohort of 1,466 WM patients who experienced histologic transformation. The 5, 10, and 15-year cumulative incidence rates were 1, 2.4, and 3.8%, respectively. Approximately half of the patients were naive to nucleoside analogues, and a quarter were previously untreated for WM at the time of transformation. More than 80% of patients presented with extranodal involvement, 65% with high IPI scores. DLBCL cells did not express CD10 but expressed BCL6 and BCL2. All patients were treated with chemoimmunotherapy. The median survival from histological transformation was 2.7 years. The median overall survival was shorter for transformed patients versus those who did not transform (estimated 9 vs. 16 years; P = 0.09). Histological transformation to DLBCL is rare, and is associated with inferior survival in WM. Am. J. Hematol. 91:1032-1035, 2016. © 2016 Wiley Periodicals, Inc.

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.

The routes for transformation of follicular lymphoma

PURPOSE OF REVIEW

Aggressive transformation, a frequent event in the natural history of follicular lymphoma, is associated with increased lymphoma-related mortality and yet the underlying biology remains poorly defined. This review outlines recent advances in our understanding of the genetic basis and evolutionary process leading to transformation.

RECENT FINDINGS

Both the antecedent indolent and transformed follicular lymphoma (tFL) arise through branched divergent evolution with tumors emerging from a founder precursor population, the common progenitor cell. Although the majority of tFLs maintain a germinal center B-cell gene expression signature, an activated B-cell-type (ABC-type) profile appears to predominate in BCL2-translocation negative cases. It does not appear that a single unifying genetic or epigenetic event promotes a fitter and more aggressive clone.

SUMMARY

Transformed follicular tumors are genetically heterogeneous perhaps reflecting the varying clinical behavior and outcomes of this disease event. Follicular lymphoma and tFL remain incurable tumors highlighted by our inability to eradicate the founder common progenitor cell population with current therapies. Progress has now been made in defining the genetic events and evolutionary pathways responsible for transformation. Although more research is required in predicting and understanding the biology of transformation, there are opportunities to improve outcomes by preferentially directing targeted therapies toward 'actionable' early and transformation-specific aberrations.

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.

Treatment of patients with transformed lymphoma

Histologic transformation (HT) is a frequent event in the clinical course of patients with indolent lymphoma. Most of the available data in the literature comes from studies on transformation of follicular lymphoma (FL), as this is the most common indolent lymphoma; however, HT is also well documented following small lymphocytic lymphoma/chronic lymphocytic leukaemia (SLL/CLL), lymphoplasmacytic lymphoma (LPL), or marginal zone lymphoma (MZL), amongst other types of lymphoma, albeit most of the studies on transformation in these subtypes are case reports or short series. The outcome of patients with HT has traditionally been considered dismal with a median overall survival (OS) of around 1 year in most of the published studies. This prompted many authors to include stem cell transplant (SCT) as part of the treatment strategy for young and fit patients with HT. However, recent articles suggest that the outcome of patients with transformed lymphoma might be improving, questioning the need for such intensive therapies. The management of patients with HT is challenged by the heterogeneity of the population in terms of previous number and type of therapy lines and from their exclusion from prospective clinical trials. This review will examine whether the advent of new therapies has impacted on the prognosis of HT and on current treatment strategies.