The value of positron emission tomography in prognosis and response assessment in non-Hodgkin lymphoma

Role of Radiation Therapy Differs Between Stages in Primary Bone Large B-Cell Lymphoma in Rituximab Era: A Population-Based Analysis

Background: Primary bone B-cell lymphoma (PB-DLBCL) is a rare entity for which existing data is limited. Whether radiotherapy (RT) should be omitted in the modern treatment of PB-DLBCL is still under debate. We used the SEER database to compare the outcomes among adult patients treated with and without RT in rituximab era. Methods: We included adult patients with PB-DLBCL diagnosed from 2002 to 2016 from SEER 18. The effect of RT on overall survival (OS) using univariate (UVA) and multivariate (MVA) Cox proportional regression and propensity score matching (PSM) was assessed for the entire cohort and subgroups by stages. We calculated the standardized incidence ratio to estimate the short- and long-term risk for second primary malignancies (SPM) from 2002 to 2016 in SEER 18 and 1983-2016 in SEER 9. Results: A total of 1,320 patients were identified, including 856 with early-stage (ES) and 464 with advanced-stage (AS). A decreasing trend was observed in the ES cohort after 2002, while the rate of RT utilization remained stable in the AS cohort over the past three decades. Most patients in ES (63.9%) underwent RT, whereas only 42.2% of AS patients received it. RT significantly improved survival both in UVA and MVA (P < 0.001, P = 0.010, respectively). PSM analysis further validated the survival advantage of RT (P = 0.018). Moreover, a novel web-based prediction model was established to individualize the potential benefit from RT. In subgroup analyses, OS was improved with RT in those who had ES disease (p < 0.001) but not in those who had AS disease (P = 0.776). With short-term follow up in SEER 18, none of the subgroups showed a significantly elevated risk of developing SPMs. However, RT significantly elevated the late toxicities of second malignancies in ES patients diagnosed at the age of 18-39 or those with appendicular sites of bone involvement. Conclusion: This population-based analysis is the largest PB-DLBCL dataset to date and demonstrates a significant survival benefit associated with RT in early stages rather than advanced stages. In the absence of randomized controlled trials, RT should be considered in ES disease with cautions of second cancers in specific subsets of patients.

Burkitt lymphoma in adolescents and young adults: management challenges

About one-half of all Burkitt lymphoma (BL) patients are younger than 40 years, and one-third belong to the adolescent and young adult (AYA) subset, defined by an age between 15 and 25-40 years, based on selection criteria used in different reports. BL is an aggressive B-cell neoplasm displaying highly characteristic clinico-diagnostic features, the biologic hallmark of which is a translocation involving immunoglobulin and c-MYC genes. It presents as sporadic, endemic, or epidemic disease. Endemicity is pathogenetically linked to an imbalance of the immune system which occurs in African children infected by malaria parasites and Epstein-Barr virus, while the epidemic form strictly follows the pattern of infection by HIV. BL shows propensity to extranodal involvement of abdominal organs, bone marrow, and central nervous system, and can cause severe metabolic and renal impairment. Nevertheless, BL is highly responsive to specifically designed short-intensive, rotational multiagent chemotherapy programs, empowered by the anti-CD20 monoclonal antibody rituximab. When carefully applied with appropriate supportive measures, these modern programs achieve a cure rate of approximately 90% in the average AYA patient, irrespective of clinical stage, which is the best result achievable in any aggressive lymphoid malignancy to date. The challenges ahead concern the following: optimization of management in underdeveloped countries, with reduction of diagnostic and referral-for-care intervals, and the applicability of currently curative regimens; the development of lower intensity but equally effective treatments for frail or immunocompromised patients at risk of death by complications; the identification of very high-risk patients through positron-emission tomography and minimal residual disease assays; and the assessment in these and the few refractory/relapsed ones of new monoclonals (ofatumumab, blinatumomab, inotuzumab ozogamicin) and new molecules targeting c-MYC and key proliferative steps of B-cell malignancies.

International Pediatric Non-Hodgkin Lymphoma Response Criteria

PURPOSE

Response criteria are well established for adult patients with non-Hodgkin lymphoma (NHL). A revised set of response criteria in adults with NHL was recently published. However, NHL in children and adolescents involves different histologies, primary sites of disease, patterns of metastatic spread, approaches to therapy, and responses to treatment compared with adult NHL. However, there are no standardized response criteria specific to pediatric NHL. Therefore, we developed international standardized methods for assessing response to therapy in children and adolescents with NHL.

METHODS

An international multidisciplinary group of pediatric oncologists, pathologists, biologists, and radiologists convened during and after the Third and Fourth International Childhood, Adolescent and Young Adult NHL Symposia to review existing response and outcome data, develop methods for response evaluation that reflect incorporation of more sensitive technologies currently in use, and incorporate primary and metastatic sites of disease for the evaluation of therapeutic response in children and adolescents with NHL.

RESULTS

Using the current adult NHL response criteria as a starting point, international pediatric NHL response criteria were developed incorporating both contemporary diagnostic imaging and pathology techniques, including novel molecular and flow cytometric technologies used for the determination of minimal residual disease.

CONCLUSION

Use of the international pediatric NHL response criteria in children and adolescents receiving therapy for NHL incorporates data obtained from new and more sensitive technologies that are now being widely used for disease evaluation, providing a standardized means for reporting treatment response.

Heterogeneous bone marrow uptake on interim 18F-fluorodeoxyglucose positron emission tomography for lymphoma mimicking disease progression: a case report

Introduction

The use of ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) scanning for baseline staging and assessment of treatment response for higher grade lymphomas is considered to be the standard of care. Evaluation of lymphomatous bone marrow infiltration on ¹⁸F-FDG PET can usually distinguish between normal regenerating marrow following chemotherapy by a characteristic pattern of uptake.

Case presentation

Here we report the case of a 51-year-old Caucasian woman with mixed low- and high-grade lymphoma with biopsy confirmed marrow infiltration. An interim post-three cycle chemotherapy ¹⁸F-FDG PET scan revealed apparent progression of marrow disease. Subsequent investigations were performed including bone marrow biopsies, repeat ¹⁸F-FDG PET scanning and a white cell scan. These revealed the interim ¹⁸F-FDG PET scan appearance was due to a highly unusual pattern of scattered islands of regenerating normal marrow, rather than progressive lymphoma.

Conclusions

Our case report highlights that apparent severe bone marrow abnormalities on ¹⁸F-FDG PET scans in lymphoma patients treated with chemotherapy are not always due to disease. Clinicians should retain a high index of suspicion for benign causes when ¹⁸F-FDG PET scan results appear incongruent with clinical response.

Quantitative and qualitative analysis of metabolic response at interim positron emission tomography scan combined with International Prognostic Index is highly predictive of outcome in diffuse large B-cell lymphoma

The prognostic value of interim (18)fluorodeoxyglucose positron emission tomography (i-PET) was investigated in 73 patients (median age 60 years) with diffuse large B-cell lymphoma (DLBCL). i-PET was analyzed using the Deauville score (DS) and change in maximum standardized uptake value (ΔSUV(max)). Patients with a DS of 1-3 demonstrated a significantly (p < 0.0001) better outcome (median follow-up 2.4 years) than patients with a score of 4 or 5 in terms of event-free survival (EFS) (79% vs. 36%), progression-free survival (PFS) (84% vs. 47%) and overall survival (OS) (91% vs. 51%). EFS (73% vs. 42%), PFS (78% vs. 50%) and OS (88% vs. 56%) were also significantly (p = 0.023) different between patients with ΔSUV(max) > 66% or ≤ 66%. Patients (n = 33) combining a favorable age-adjusted International Prognostic Index (IPI) (0 or 1) and a negative i-PET either by DS or ΔSUV(max) criteria showed a particularly good outcome (EFS: 85%, PFS: 88%, OS: 94%). Overall, i-PET was highly and independently predictive of any outcome, and its negative predictive value was improved by combination with IPI.

Gray zone lymphoma: better treated like hodgkin lymphoma or mediastinal large B-cell lymphoma?

Although primary mediastinal large B-cell lymphoma (PMBL) and classic Hodgkin lymphoma of the nodular sclerosis type (CHL-NS) are distinct diseases, they share several clinical characteristics and biologic features. Given that, it is not surprising that there exist mediastinal lymphomas that do not fit well into either category but have clinical and morphologic features overlapping and transitional between PMBL and CHL-NS. The term mediastinal gray zone lymphoma (MGZL) has been used for these tumors, which are included in the World Health Organization classification as "B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classic Hodgkin lymphoma." Although several studies have evaluated different therapeutic strategies in PMBL and CHL-NS, there is a paucity of prospective experience treating MGZL, given its rarity and relatively recent recognition. Historically, diseases that today would be categorized as MGZL were probably called "anaplastic large-cell lymphoma Hodgkin-like," and their outcome with standard approaches was poor, with short overall survivals. In this review-following a discussion of the biology and clinical features of MGZL, and how they compare to PMBL and CHL-NS-we outline how the treatment of PMBL and CHL-NS has evolved in recent years, and how we believe MGZL should be approached therapeutically.

Pediatric nonlymphoblastic non-Hodgkin lymphoma: baseline, interim, and posttreatment PET/CT versus contrast-enhanced CT for evaluation--a prospective study

PURPOSE

To prospectively examine the roles of positron emission tomography (PET)/computed tomography (CT) and conventional contrast material-enhanced CT at baseline, after two cycles of chemotherapy, and after completion of chemotherapy in pediatric patients with nonlymphoblastic non-Hodgkin lymphoma (NHL) who were treated with similar standard treatment protocols.

MATERIALS AND METHODS

The institutional ethics committee approved the study protocol, and all patients were enrolled after written informed consent was obtained. Patients with nonlymphoblastic NHL were prospectively enrolled between January 2008 and March 2010. Patients underwent contrast-enhanced CT and PET/CT for staging and for response assessment after two cycles of chemotherapy (interim) and treatment completion. Complete metabolic response versus no metabolic response at PET/CT and complete response versus no complete response at contrast-enhanced CT was analyzed by using Kaplan-Meier survival analysis.

RESULTS

The final study included 34 patients with nonlymphoblastic NHL (median age, 10.5 years). Baseline PET/CT and contrast-enhanced CT showed concordance in depiction of 112 disease sites; PET/CT depicted 18 more disease sites and two fewer disease sites than contrast-enhanced CT (P = .0003). Disease in five of 34 patients was upstaged, and disease in no patient was downstaged at PET/CT. There was 100% (four of four) concordance between bone marrow involvement at biopsy and stage at PET/CT. The median length of follow-up was 20.3 months. Response at interim PET/CT and contrast-enhanced CT could not predict progression-free survival (PFS) (P = .083 and .18, respectively) or overall survival (OS) (P = .159 and.08, respectively). Posttreatment PET/CT and contrast-enhanced CT findings could predict PFS (P = .036 and .002, respectively) and posttreatment contrast-enhanced CT findings could predict OS (P = .035); however, posttreatment PET/CT findings could not predict OS (P = .067).

CONCLUSION

PET/CT depicts additional sites compared with contrast-enhanced CT and results in upstaging of disease. Either PET/CT or contrast-enhanced CT may be used for response assessment and prognostication in stage III or IV nonlymphoblastic pediatric NHL.

How I treat HIV-associated lymphoma

Over the past 10 years, significant progress has been made in understanding HIV-associated lymphomas and improving the prognosis of these diseases. With the advent of combination antiretroviral therapy and the development of novel therapeutic strategies, most patients with HIV-associated lymphomas are cured. The outcome for the majority of patients with HIV-associated diffuse large B-cell lymphoma and Burkitt lymphoma in particular, is excellent, with recent studies supporting the role of rituximab in these diseases. Indeed, in the combination antiretroviral therapy era, the curability of many patients with HIV-associated lymphoma is similar to their HIV-negative counterparts. New treatment frontiers need to focus on improving the outcome for patients with advanced immune suppression and for those with adverse tumor biology, such as the activated B-cell type of diffuse large B-cell lymphoma and the virally driven lymphomas. Future clinical trials need to investigate novel targeted agents alone and in combination with chemotherapy.

Burkitt lymphoma: staging and response evaluation

The refinements in both the staging and response evaluation of children with Burkitt lymphoma (BL) have contributed to the improvements in treatment outcome observed over the past 40 years. Ziegler and Magrath designed a staging system in the 1970s for children with BL in equatorial Africa. Currently, the most widely used staging system around the world is that described by Murphy in 1980, which was developed for children with non-Hodgkin lymphoma (NHL) of any histology. There are opportunities for refinement in this system, particularly with respect to certain extra-nodal sites, such as skin and bone. The findings obtained at diagnosis with novel technologies (functional imaging [e.g., positron emission tomography [PET]] and minimal residual disease [MRD] technology), which are more sensitive with respect to disease detection than historic modalities, also need to be considered. Technological advances have also had impact on the assessment of response evaluation. Standard x-rays were routinely used in the 1960s; nuclear imaging became widely used in the 1970s; computerized axial tomography was incorporated in the 1980s; PET imaging was incorporated and, in many cases, has replaced gallium/bone scans since 2000; and MRD technology has been explored in some of the most recent clinical trials. There is clearly a need for more clinical data on the use of PET and MRD technology in the determination of response evaluation of children with BL as well as other histological subtypes of NHL. An international working group is currently addressing the refinement of both disease staging and response evaluation in children with NHL.

Lack of survival improvement in patients with peripheral T-cell lymphoma: a Surveillance, Epidemiology, and End Results analysis

In patients with aggressive non-Hodgkin lymphomas (NHLs), T-cell lymphoma (TCL) confers a poor prognosis. Since rituximab has increased survival for patients with diffuse large B-cell lymphoma (DLBCL), we hypothesized that the difference in outcome by phenotype became more pronounced recently and evaluated these changes using the Surveillance, Epidemiology, and End Results (SEER) Program. Cases diagnosed in 1992-1997 (era 1) and 1998-2003 (era 2) were evaluated for outcomes according to immunophenotype and era. A total of 22,252 patients with DLBCL and 2222 with TCL were included. In both eras, patients with TCL were more likely to die from their disease than those with DLBCL. Death from NHL decreased significantly from era 1 to era 2 for all DLBCL patients grouped by age and stage but in none of the TCL groups. Improved outcomes for DLBCL after the introduction of rituximab-based therapies in 1997 have no counterpart in patients with TCL, pointing to the need for new therapies to treat TCL.