Special issues in pediatric Hodgkin's disease

Classic Hodgkin lymphoma in young people

Classic Hodgkin lymphoma (CHL) is a unique form of lymphoid cancer featuring a heterogeneous tumor microenvironment and a relative paucity of malignant Hodgkin and Reed-Sternberg (HRS) cells with characteristic phenotype. Younger individuals (children, adolescents and young adults) are affected as often as the elderly, producing a peculiar bimodal age-incidence profile that has generated immense interest in this disease and its origins. Decades of epidemiological investigations have documented the populations most susceptible and identified multiple risk factors that can be broadly categorized as either biological or environmental in nature. Most risk factors result in overt immunodeficiency or confer more subtle alterations to baseline health, physiology or immune function. Epstein Barr virus, however, is both a risk factor and well-established driver of lymphomagenesis in a significant subset of cases. Epigenetic changes, along with the accumulation of somatic driver mutations and cytogenetic abnormalities are required for the malignant transformation of germinal center-experienced HRS cell precursors. Chromosomal instability and the influence of endogenous mutational processes are critical in this regard, by impacting genes involved in key signaling pathways that promote the survival and proliferation of HRS cells and their escape from immune destruction. Here we review the principal features, known risk factors and lymphomagenic mechanisms relevant to newly diagnosed CHL, with an emphasis on those most applicable to young people.

Hodgkin Lymphoma in Children and Adolescents: Advances in Pathology, Diagnosis, and Treatment Strategies

Strategies used for the treatment of children with Hodgkin lymphoma (HL) over the last four decades have resulted in excellent long-term survivals. However, the short- and long-term treatment-associated morbidities were high. In an attempt to reduce complications, the current treatment strategies apply initial risk stratification principles based on certain host and tumor risk factors to help assign patients to the appropriate risk group and tailor therapy based on response to chemotherapy (CTR). Radiotherapy (RT) was only given to certain groups of patients who show suboptimal response to CTR. Enrollment of patients in clinical trials allowed testing newer treatment strategies, which has improved the outcome significantly. High-dose CTR with stem cell support remains the mainstay of treatment for relapsed and refractory HL. Newer targeted medications are being increasingly used for the treatment of patients with relapsed and refractory HL, but results are variable. In this review report, we give extensive account about the pathophysiology, clinical presentation, histopathological diagnosis, modern investigation techniques, the most recent risk adapted treatment strategies, and the use and effect of novel medications. In addition, we discuss in details the short- and long-term therapy-related complications and future prospects in the management of HL.

Outcomes in intermediate-risk pediatric lymphocyte-predominant Hodgkin lymphoma: A report from the Children's Oncology Group

PURPOSE

Optimal management of patients with intermediate-risk lymphocyte-predominant Hodgkin lymphoma (LPHL) is unclear due to their small numbers in most clinical trials. Children's Oncology Group AHOD0031, a randomized phase III trial of pediatric patients with intermediate-risk Hodgkin lymphoma (HL), included patients with LPHL. We report the outcomes of these patients and present directions for future therapeutic strategies.

PROCEDURE

Patients received two cycles of doxorubicin, bleomycin, vincristine, etoposide, prednisone, and cyclophosphamide (ABVE-PC) followed by response evaluation. Slow early responders were randomized to two additional ABVE-PC cycles ± two dexamethasone, etoposide, cisplatin, and cytarabine cycles and all received involved field radiotherapy (IFRT). Rapid early responders (RERs) received two additional ABVE-PC cycles. RERs with complete response (CR) were randomized to IFRT or no further therapy. RERs without CR received IFRT.

RESULTS

Ninety-six (5.6%) of 1711 patients on AHOD0031 had LPHL. Patients with LPHL were more likely to achieve RER (93.6% vs. 81.0%; P = 0.002) and CR (74.2% vs. 49.3%; P = 0.000005) following chemotherapy compared with patients with classical HL. Five-year event-free survival (EFS) was superior in patients with LPHL (92.2%) versus classical HL (83.5%) (P = 0.04), without difference in overall survival (OS). Among RERs with CR following chemotherapy (n = 33), there was no difference in EFS or OS between those randomized to receive or not receive IFRT.

CONCLUSION

Children and adolescents with intermediate-risk LPHL represent ideal candidates for response-adapted therapy based on their favorable outcomes. The majority of patients treated with the ABVE-PC backbone achieve RER with CR status and can be treated successfully without IFRT.

Relapsed or poorly responsive nodular lymphocyte predominant Hodgkin lymphoma in children and adolescents - a report from the United Kingdom's Children's Cancer and Leukaemia Study Group

There is a paucity of data on the treatment outcome in children with relapsed or poorly responsive nodular lymphocyte predominant Hodgkin lymphoma (nLPHL). This retrospective report evaluates the treatment outcome in a national cohort of children with relapsed or poorly responsive nLPHL. A total of 37 patients, 22 with relapsed and 15 with poorly responding disease, are the subjects of this report. Of the 22 patients with relapsed nLPHL, 11 had relapsed after primary excision biopsy, 10 after chemotherapy and 1 after chemotherapy and involved field radiotherapy. The majority had localized disease at relapse. The median time to relapse was 8 months after chemotherapy and 11 months after excision biopsy. Seven of the 15 patients with poorly responding nLPHL had variant histology. Three patients with initial poor response did not receive any further treatment and have had no disease progression. Transformation to diffuse large B cell lymphoma, in addition to evolution from typical to variant nLPHL occurred in one patient each. Thirty-four patients have been successfully re-treated with second chemotherapy or radiotherapy. Multiple relapses were uncommon but treatable. Relapse or poorly responsive nLPHL is fully salvageable with either additional chemotherapy and or radiotherapy.

Lymphocyte-Predominant Hodgkin's Disease in Children: A Case Study and Review of the Literature

A three-year-old boy presented with an enlarging neck mass. Biopsy demonstrated IgD-positive nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), which was staged as IIa. The patient received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with rituximab and had excellent results. NLPHL is a relatively rare disease that is biologically distinct from classic Hodgkin lymphoma (cHL). NLPHL is a B-cell malignancy likely of germinal center origin that has an overall good prognosis and favorable response to treatment. Unlike cHL, NLPHL is ubiquitously CD20-positive. Recent evidence supports the efficacy of targeted anti-CD20 therapy in NLPHL, though prospective data is limited. This case demonstrates several unique features of NLPHL and further supports the use of rituximab in front-line therapy. The clinical characteristics among patients at various ages are discussed with a special focus on the IgD-positive subtype. A thorough literature search demonstrates this to be the youngest patient with NLPHL yet described.

Hodgkin lymphoma--a survey of children and adolescents treated in Sweden 1985-2009

BACKGROUND

Hodgkin lymphoma (HL) in children constitutes approximately 30% of all pediatric lymphomas in Sweden. The chance of cure is high, but the frequency of late effects has been considerable. Over recent years, efforts have been made to reduce treatment with maintained survival.

MATERIAL AND METHODS

All patients 0-17 years, identified in the Swedish Childhood Cancer Register as diagnosed between 1985 and 2009, were included. The material was analyzed using descriptive statistics and for survival estimates the Kaplan-Meier method was used.

RESULTS

Three hundred and thirty-four patients were identified during this time period. The median age was 14 years. Male sex was over-represented, especially in lower age groups and in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). In nodular sclerosis and in age group 15-17 years, female sex dominated. Most of the cases presented in stages I or II. B-symptoms were present in 38% of cHL, but only in 7% of NLPHL. The number of patients receiving radiotherapy has been significantly reduced during the period studied. The relapse rate in cHL was 10 ± 2% and in NLPHL 16 ± 7%. The relapse rate was significantly higher in cHL stage IIB compared to other stages in the same therapy group. In cHL 6% died, and in NLPHL 0%. The 5-, 10- and 20-year overall survival estimates in cHL were 96 ± 1%, 95 ± 1% and 90 ± 3%, respectively, with no significant difference when comparing different treatment regimens and time periods. The 5- and 10-year overall survival after relapse in cHL was 81 ± 8% and 75 ± 10%, respectively.

CONCLUSION

During the period studied there is no indication of a decline in survival despite changes in treatment. Survival rates in Sweden are high, and even after relapse chances of cure are high. We were not able to identify any characteristics specific for the group of patients that did not survive.

[Pediatric Hodgkin disease in North Tunisia: clinical and therapeutic study]

PURPOSE

To assess the epidemiological, clinical and therapeutic aspects of pediatric Hodgkin disease (HD) and to study prognosis factors.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of children (≤18 years) with HD treated between 1st January 1994 and 31st December 2004. Chemotherapy was undertaken in different departments of hematology and oncology in the North of the country and radiotherapy was centralized at the Salah-Azaïz National Cancer Institute.

RESULTS

One hundred fourteen consecutively treated patients were collected. Median age was 12 years (4-18 years) and sex-ratio was 2.25. Peripheral lymphadenopathy was the predominant circumstance of HD detection (82.5%). The predominant histologic type was nodular sclerosing (56%). Treatment included chemotherapy and involved-field radiotherapy. With a mean follow-up of 23.5 months, relapse rate was 12.2%. Five-year overall survival (OS) and event-free survival (EFS) rates were 95% and 76%, respectively. Five-year OS was 98.2% and 90.8% for early and advanced stages respectively. In multivariate analysis, stage IV (P=0.029) and early response to initial treatment (P=0.003) retained statistical significance for EFS whereas the only prognostic factor for OS was stage IV (P=0.002). The long-term side effects were rare. No secondary tumor was noted.

CONCLUSION

Combined-modality therapy using chemotherapy and involved-field radiotherapy was effective and well-tolerated in early stage pediatric HD. Stage IV patients should be referred to specialized units for intensive treatment. The short median follow-up in our study cannot allow considering long-term effects.

Nodular lymphocyte predominant Hodgkin lymphoma in children and adolescents--a comprehensive review of biology, clinical course and treatment options

Nodular lymphocyte predominant Hodgkin lymphoma (nLPHL) is a unique variant of Hodgkin lymphoma with an overall good prognosis. It is conspicuously different from classical Hodgkin lymphoma (cHL) and is now recognized as distinctive form of B cell lymphoma. Although it has an indolent clinical course, it has a propensity for multiple and often late relapses. Although the majority of children present with early stage disease and without B symptoms, treatment strategy has, until recently, been identical to that used for cHL. This approach is excessively toxic as it predisposes these children and adolescents to serious late effects including end organ damage to heart, gonads, lungs, thyroid and second malignant neoplasms. The aim of this article is to review the published literature on the treatment outcomes of nLPHL in affected children and adolescents, and discuss the options for treatment including surgery, chemotherapy, radiotherapy and targeted anti-CD 20 antibody therapy.

Surveillance computed tomography imaging and detection of relapse in intermediate- and advanced-stage pediatric Hodgkin's lymphoma: a report from the Children's Oncology Group

PURPOSE Children with Hodgkin's lymphoma (HL) routinely undergo surveillance computed tomography (CT) imaging for up to 5 years after therapy, resulting in cost and radiation exposure, without clear benefit. The objective of this study was to determine the contribution of surveillance CT, as compared with clinical findings, to detection of disease recurrence. PATIENTS AND METHODS Two hundred sixteen patients, age ≤ 21 years old, were treated on the multicenter Pediatric Oncology Group 9425 trial. Data for patients who experienced relapse were retrospectively reviewed to determine whether imaging or clinical events prompted suspicion of disease recurrence. Correlation was made to disease stage, time to recurrence, relapse site, and overall survival (OS). Results With a median follow-up time of 7.4 years, 25 (11.6%) of 216 patients had experienced a relapse, of whom 23 experienced local relapse. Median time to relapse was 7.6 months (range, 0.2 to 48.9 months). Nineteen relapses (76%) were detected based on symptoms, laboratory or physical examination findings, and two relapses (8%) were detected by imaging within the first year after therapy. Only four patients (16%) had their recurrence detected exclusively by surveillance imaging after the first year. Six deaths occurred, all in patients who experienced relapse within the first year after therapy. No patient with a recurrence after 1 year off treatment has died, regardless of how the recurrence was detected. CONCLUSION The majority of pediatric HL relapses occurred within the first year after therapy or were detected based on change in clinical status. Detecting late relapse, whether by imaging or clinical change, did not affect OS. These findings indicate that CT is overused for routine surveillance of patients with HL.

Refining the role of radiation therapy in pediatric hodgkin lymphoma

The role of radiation therapy in the treatment of pediatric Hodgkin lymphoma has continued to be refined, motivated by the desire to avoid disruption to normal tissue development and function and secondary carcinogenesis. Such progress has occurred in tandem with modifications of the multiagent chemotherapy regimens that have been used in place of or in combination with low-dose involved-field radiation that are also associated with dose-related risks of cardiopulmonary and gonadal dysfunction and leukemogenesis. Consequently, treatment strategies for young patients, who have an excellent prognosis of long-term survival, utilizes a risk-adapted approach that provides optimal efficacy for disease control whereas limiting toxicity associated with both radiation and chemotherapy. Because of the differences in age-related developmental status and gender-related sensitivity to chemotherapy and radiation toxicity, no single treatment approach is ideal for all pediatric patients. This manuscript summarizes results from published clinical trials with the goal of defining optimal treatment strategies for children and adolescents with Hodgkin lymphoma in regards to the use of radiation therapy.

Leukemia and lymphoma

Leukemia and lymphoma are the most common and third most common pediatric malignancies, respectively, and share cell lineages, but the clinical and imaging manifestations of these malignancies vary substantially. Along with providing pertinent details on classification, epidemiology, and treatment, this article reviews the current roles of imaging in the management of childhood leukemia and lymphoma, with attention to diagnosis, staging, risk stratification, therapy response assessment, and surveillance for disease relapse and adverse effects of therapy. Advances in functional imaging are also discussed to provide insights into future applications of imaging in the management of pediatric patients with leukemia and lymphoma.

Comparing adult and pediatric Hodgkin lymphoma in the Surveillance, Epidemiology and End Results Program, 1988-2005: an analysis of 21 734 cases

We analyzed data from 18 898 adults (age ≥20 years) and 2836 children/adolescents reported in the Surveillance, Epidemiology and End Results (SEER) database as having Hodgkin lymphoma (HL), diagnosed from 1988 to 2005. The nodular sclerosis subtype was significantly more common in the pediatric age group (76% in children/adolescents vs. 61% in adults, p < 0.001). The mixed cellularity subtype was more prevalent in children <10 years old (22%), but less likely in older children/adolescents (8.5%). Systemic symptoms were reported in 39% of children/adolescents and in 48% of adults (p < 0.001). Children/adolescents had significantly better HL-specific survival than adults (5-year survival rate, 96% ± 0.4% vs.88% ± 0.3%, p < 0.001). Using a Cox proportional-hazards regression model in patients with classical HL, the prognostic factors significantly impacting survival were age, histology, stage, B symptoms, year of diagnosis, and race. The only adverse prognostic factors that were significant when this analysis was restricted to children/adolescents were stage IV disease and the presence of B symptoms. In conclusion, several differences in clinicopathologic features and outcomes were identified between children/adolescents and adults with HL, and this was particularly noted in young children (<10 years).

(18)F-FDG PET in Pediatric Lymphomas: A Comparison with Conventional Imaging

This study reports on our experience with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in pediatric patients affected by Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). We studied 20 pediatric subjects (12 males, 8 females; mean age, 10 years; range, 6 months to 14 years) with malignant lymphoma (9 HD, 11 NHL) for a 4-year period of time. Overall, 45 PET scans were performed: 7 at disease presentation and 38 for evaluation of response to therapy or follow-up study. All PET results were compared with conventional imaging (CI), mainly computed tomography (CT) and/or magnetic resonance imaging (MRI), and supported by clinical follow-up and/or histologic data. In 18 of 20 patients, PET findings correctly identified the status of disease. Two (2) subjects (respectively, 1 HD and 1 NHL, both at follow-up) resulted falsely positive: 1 due to prominent thymic uptake, and the other due to nonspecific inflammation. Of 45 scans, PET findings were consistent with clinical follow-up and other CI data in 43 cases (16 true-positive and 27 true-negative results) and resulted falsely positive in the remaining 2 scans. On a lesion-by-lesion basis (overall, 153 lesions: 84 nodal and 69 extranodal), we found a concordance between CI and PET findings in 25 nodal (29.8%) and in 22 extranodal sites (32%). PET was more accurate than CI, as it identified active disease in 1 patient negative at CI and excluded relapse in 6 patients with inconclusive CI and in 2 patients with a falsely positive CI. Overall, PET sensitivity and specificity was 100% and 93% versus 94% sensitivity and 72.4% specificity for CI. This comparative study shows FDG PET to be more accurate than CI in evaluating children with lymphoma. Our data also confirms that (18)F-FDG PET may show false-positive findings.

Pediatric lymphomas in Brazil

OBJECTIVE

This study provides the clinical pathological characteristics of 1301 cases of pediatric/adolescent lymphomas in patients from different geographic regions of Brazil.

METHODS

A retrospective analyses of diagnosed pediatric lymphoma cases in a 10-year period was performed. We believe that it represents the largest series of pediatric lymphomas presented from Brazil.

RESULTS

Non-Hodgkin lymphomas represented 68% of the cases, including those of precursor (36%) and mature (64%) cell origin. Mature cell lymphomas comprised 81% of the B-cell phenotype and 19% of the T-cell phenotype. Hodgkin lymphomas represented 32% of all cases, including 87% of the classical type and 13% of nodular lymphocyte predominant type. The geographic distribution showed 38.4% of the cases in the Southeast region, 28.7% in the Northeast, 16.1% in the South, 8.8% in the North, and 8% in the Central-west region. The distribution by age groups was 15-18 years old, 33%; 11-14 years old, 26%; 6-10 years old, 24%; and 6 years old or younger, 17%. Among mature B-cell lymphomas, most of the cases were Burkitt lymphomas (65%), followed by diffuse large B-cell lymphomas (24%). In the mature T-cell group, anaplastic large cell lymphoma, ALK-positive was the most prevalent (57%), followed by peripheral T-cell lymphoma, then not otherwise specified (25%). In the group of classic Hodgkin lymphomas, the main histological subtype was nodular sclerosis (76%). Nodular lymphocyte predominance occurred more frequently than in other series.

CONCLUSION

Some of the results found in this study may reflect the heterogeneous socioeconomical status and environmental factors of the Brazilian population in different regions.

Maladie de Hodgkin de l'enfant dans le sud tunisien: étude de 23 cas

PURPOSE

To discuss, through a retrospective study, the epidemiologic and anatomo-clinic aspects of paediatric Hodgkin disease (HD) in south Tunisia and to study the faisability of the French protocol MDH 90 for our patients.

PATIENTS AND METHODS

Between January 1995 and December 2000, we treated 23 children with HD. Initial work-up included clinical examination, radiological explorations (chest X ray, abdomen ultrasonography and computed tomography scan of chest, abdomen and pelvis), biological explorations (full blood count, erythrocyte sedimentation rate, serum albumin, liver functions tests) and a bone marrow biopsy. Treatment was inspired from the SFOP MDH 90 protocol. Overall survivals and disease free survivals were estimated with Kaplan-Meier method and compared with the log-rank test.

RESULTS

Mean age was 8.6 years (4-14 years), sex-ratio was 3.6. Histological subtypes 2 and 3 had the same frequency. Localised stages (I-II) were as frequent as advanced stages (III-IV). At the end of the treatment, the 18 evaluables patients were in complete remission. The 5-year overall survival (OS) and disease free survival (DFS) were 82 and 76% respectively. Localised stages and advanced stages had the same 5-year overall survival (82%). There were no statistical differences in term of OS between the different prognosis factors studied.

CONCLUSIONS

The particularity of our study was the identical frequency of the two histological subtypes 2 and 3 and of localised and advanced stages. The MDH 90 protocol is feasable for our patients with satisfactory results similar to those found in the literature.

Is age an independent risk factor for chemically induced acute myelogenous leukemia in children?

Secondary or therapy-related acute myelogenous leukemia (t-AML) is a rare but unfortunate consequence of treatment with certain classes of cytotoxic chemotherapeutic agents or chronic exposure to high concentrations of benzene. Drugs known to produce AML following chemotherapy of primary malignancy are usually alkylating agents or topoisomerase II inhibitors. Both children and adults develop AML following treatment with these classes of antineoplastic drugs. In this review, the effect of age at treatment on a child's susceptibility to developing therapy related AML was investigated. The clinical literature describing pediatric cancer patients treated with cytotoxic chemotherapeutic agents was used to characterize risk factors associated with chemical leukemogenesis in children. As demonstrated in the published literature, the risk of developing AML following chemotherapy is not reliably correlated with the age of the pediatric patient. There is no consistent evidence that indicates that younger children will be at increased risk; in fact, some studies suggest that younger children might actually display a decreased susceptibility. The age dependency of treatment-related malignancies (all types) in children appears to vary considerably with the type of secondary neoplasm in question. For example, secondary solid tumors such as breast, central nervous system (CNS), bone, and thyroid cancer are highly dependent on the age of the patient at time of diagnosis and treatment; in contrast, an age dependency for t-AML risk was not observed in these same patient populations. Predictably, the induction of t-AML in children follows a rational dose-response relationship, with increasing doses of chemotherapy resulting in greater risk. Recent U.S. Environmental Protection Agency (EPA) cancer risk assessment guidance recommends a default assumption that children are inherently up to 10-fold more sensitive than adults to carcinogen exposures. Available scientific and medical literature does not support the hypothesis that children necessarily possess an increased risk of developing AML following leukemogenic chemical exposure.

Pediatric Hodgkin Lymphoma: Maximizing Efficacy and Minimizing Toxicity

Historically, both adult and childhood Hodgkin lymphoma (HL) were treated with full-dose (35-45 Gy) extended-field radiation therapy (RT). Although this treatment was the first to produce reliable disease control, the resulting late toxicity led pediatric oncologists to pioneer the use of combined chemotherapy and low-dose (15-25 Gy) involved-field RT for all stages of HL. Currently, standard treatment of childhood HL is risk adapted; those with favorable risk disease typically receive 2 to 4 cycles of multi-agent chemotherapy with low-dose IFRT, whereas those with higher-risk disease receive more intensive chemotherapy before IFRT. This approach produces long-term survival rates >90% while limiting exposure to anthracyclines, alkylators, and radiation to normal tissues. In contrast to adult HL, IFRT remains an important component of the treatment of advanced-stage HL in pediatric patients. Current clinical trials for children with HL aim to further segregate patients into risk strata such that those who are highly curable can receive less toxic therapy, whereas high-risk patients can receive augmented therapy. Response-adapted therapy, in which overall treatment intensity is modified according to the initial response to chemotherapy, is emerging as a potential means of further reducing therapy for some while maintaining high cure rates. The challenge is to refine therapy in a rare disease in which long-time intervals are necessary to observe an adequate number of events (treatment failure or late effects) to answer judicious questions.