The role of radiation therapy in the treatment of pediatric non-Hodgkin's lymphomas

Lymphoblastic lymphoma of childhood and the LSA2-L2 protocol: the 30-year experience at Memorial-Sloan-Kettering Cancer Center

BACKGROUND

Until the 1970s, diffuse lymphoblastic lymphoma (DLBL) was considered incurable. With intensive multidrug regimens, the majority of patients can now be cured. In the current study, the authors present what to their knowledge is the longest follow-up presented to date (median, 20 years for survivors) of the largest group of DLBL patients treated with a single protocol at a single institution.

METHODS

Between 1971-1990, a total of 95 consecutive patients (age < 21 years) with DLBL were treated with the LSA(2)-L(2) protocol at the Memorial Sloan-Kettering Cancer Center (MSKCC). Patients with Stage I-II disease were treated for 2 years. In 1980, the protocol was modified and patients with Stage III and IV disease were treated for 3 years. In addition, before the modification, patients with Stage IV disease received a cumulative dose of 15,600 mg/m(2) of cyclophosphamide for 3 years; after 1980, these patients received the same dosage as the other patients (i.e., 8400 mg/m(2) for 2 years). Radiation therapy initially was administered to all patients with bulky disease in the primary tumor site. Until 1977, the dose of radiation was 20-55 grays (Gy); from 1977 to 1989, the dose was 20 Gy. After the fifth year of completion of treatment, all patients were evaluated comprehensively every 2 years.

RESULTS

The overall survival (OS) of the patients was 79% with a median follow-up of 20 years. The overall event-free survival (EFS) was 75% (71 of 95 patients). Seventeen patients developed a disease recurrence and 15 died of disease. The OS and EFS rates for patients with Stages I-II disease (n = 8) were 87% and 87%, respectively, and the OS and EFS rates for patients with Stage III disease (n = 41) were 90% and 85%, respectively. The OS and EFS for patients with Stage IVA disease (with bone marrow [BM] involvement of < 25%) (n = 19) were 79% and 73%, respectively, whereas the OS and EFS for patients with Stage IVB disease (BM involvement of > 25%) (n = 27) were 74% and 70%. Of the 29 patients with Stage IV disease who were treated with the original protocol, 7 died of disease (1 of 8 patients with Stage IVA disease and 6 of 21 patients with Stage IVB disease). Of the 17 patients with Stage IV disease who were treated with the modified protocol, 3 died of disease (2 of 11 patients with Stage IVA disease and 1 of 6 patients with Stage IVB disease). Six patients developed secondary malignancies, four of whom died.

CONCLUSIONS

Long-term EFS can be achieved in the majority of patients with widely disseminated pediatric DLBL. Chemotherapy alone appears to be sufficient prophylaxis against disease recurrence in the central nervous system. No disease-related or treatment-related deaths were reported to occur > 4.5 years after diagnosis in the current study.

Non-Hodgkin's lymphomas in children. I. Patterns of disease and classification

Non-Hodgkin's lymphomas (NHL) are part of an overlapping spectrum of lympho-proliferative diseases in childhood. In the first of this 2 part series, the clinicopathological aspects of NHL in childhood are discussed. The rapid progression of disease, the high incidence of micrometastases (over 80%) at diagnosis, and the propensity of hematogenous spread to the bone marrow and the central nervous system (CNS) as well as the clinico-pathologic 'clusters' associated with particular presenting sites distinguish the pediatric forms of disease. Abdominal primary sites most frequently manifest diffuse undifferentiated (Burkitt's or non-Burkitt's) histopathology, B-cell immunophenotype, FAB-L3 cytomorphology and specific karyotypic and/or genotypic alterations of the immuno-globulin genes and the c-myc oncogene. Mediastinal presentation is associated with lymphoblastic histopathology, T-cell immunophenotype and a variety of less consistent karyotypic and genotypic aberrations. Ki-1 lymphoma, a rare subtype of large cell NHL with specific features is often of T cell origin. The requirements for diagnosis, staging and monitoring are presented in the context of the associations between clinico-pathological presentation and subsequent behavior. The most frequent sites of disease progression and relapse are involvement of the bone marrow and the CNS. For Burkitt's lymphoma there is a historic perspective and a description of particular epidemiologic, clinical, virologic, immunophenotypic and genotypic features. Cytogenetic and molecular biologic studies of genomic rearrangements are advancing the understanding of oncogenesis, clonality, lineage, and clinical behavior. The capacity to detect and amplify DNA from submicroscopic disease may contribute to prognostic stratification both at diagnosis and during subsequent monitoring.

Non-Hodgkin's lymphomas in children. II. Treatment

The prognosis of non-Hodgkin's lymphoma (NHL) in childhood has improved steadily in the last 2 decades. This is primarily the result of increasingly effective chemotherapy regimens tailored to defined and relatively homogeneous prognostic categories and tested in prospective clinical trials. Surgical excision remains of prognostic benefit only when near-total resection can be performed without delay of chemotherapy. The role of radiation therapy is now limited to the treatment of overt central nervous system (CNS) lymphoma, disease unresponsive to chemotherapy, and certain emergencies. Effective 'prophylactic' treatment of the CNS has been achieved in most series by intrathecal and systemic chemotherapy alone. The most relevant modality of treatment is chemotherapy and a very large number of protocols have been published. The origins of current multi-agent regimens stem both from early experience with cyclophosphamide in endemic Burkitt's lymphoma and from therapeutic studies of acute lymphoblastic leukaemia. Sub-stratification of non-localized NHL has produced protocols designed for either lymphoblastic (mostly T cell) or non-lymphoblastic (mostly B cell) categories. While the cure rate for lymphoblastic lymphoma now exceed 70%, the non-localized non-lymphoblastic disease remains a major obstacle to cure. These patients frequently present with large abdominal primaries and are prone to regional as well as hematogenous dissemination. In particular, involvement of the CNS is now considered to be the most adverse prognostic variable in this group. Recently, highly intensive regimens are addressing these obstacles. On the other hand, NHL defined as localized has been shown to be curable in up to 95% of children with the use of simple chemotherapy regimens as short as 6 months in duration. Salvage of patients who relapse during or after chemotherapy remains bleak but cures are possible with regimens incorporating bone marrow transplantation from either an autologous or allogeneic source. Experimental methods, including biologic and immune response modifiers may also offer future promise.

Central nervous system metastases from non-Hodgkin's lymphoma: treatment and prophylaxis

Central nervous system (CNS) lymphoma was identified in 96 patients treated for non-Hodgkin's lymphoma at Memorial Sloan-Kettering Cancer Center between 1975 and 1981. During the same period, 68 other patients with non-Hodgkin's lymphoma but no CNS disease received prophylactic CNS chemotherapy. In the 156 total patients, the lymphomas were diffuse in 96 percent, and 67 percent were stage IV at diagnosis. CNS involvement was present at initial diagnosis in 27 percent, at relapse in 26 percent, and during the course of progressive systemic disease in 47 percent. CNS involvement was asymptomatic in 10 percent. Cytologic study of the cerebrospinal fluid was the most sensitive and specific laboratory test, but often (22 percent) more than one lumbar puncture was required to identify malignant cells. CNS lymphoma was treated in 85 patients, 46 by intracerebroventricular cannulae; 81 percent improved. Although median survival after the diagnosis of CNS disease was four months, there were seven long-term disease-free survivors and the CNS disease contributed to death in only 14 percent. In 52 percent of treated patients, there was no CNS lymphoma at autopsy. CNS prophylaxis was with methotrexate or cytosine arabinoside, usually by lumbar puncture; an intraventricular cannula was used in seven patients. Although this group of high-risk patients with non-Hodgkin's lymphoma had a high systemic response rate and the median projected survival was greater than five years, CNS lymphoma developed in eight patients (12 percent). In five, CNS lymphoma occurred as an apparently isolated relapse site. The role of CNS chemoprophylaxis in high-risk patients with non-Hodgkin's lymphoma is still uncertain.

Intensive chemotherapy for non-localised Burkitt's lymphoma

Between 1982 and 1984, 24 consecutively diagnosed children from Iraq with non-localised Burkitt lymphoma (Murphy stages II, III, and IV) were eligible for treatment with a multi-drug rotating chemotherapy schedule. This schedule was intensive and included early treatment directed at the central nervous system but was of only six months' duration and fairly inexpensive compared with schedules recently advocated for use in the developed world. Some patients had 'debulking' abdominal surgery, but no radiation treatment was used. There were a number of complications related to early treatment, some of them fatal, but of 13 patients entering complete remission 12 are long term survivors who are free of disease and, hopefully, cured. These results represent a substantial improvement over our experience before 1982 (6.9% survival). A similar treatment approach might be adopted by other centres, especially those in developing countries where cancer accounts for a rising proportion of childhood death but whose resources are limited.

Studies on the pathology of non-Hodgkin's lymphoma of childhood. I. The role of routine histopathology as a prognostic factor. A report from the Children's Cancer Study Group

Between April 1977, and August 1980, the Children's Cancer Study Group (CCSG) conducted a clinical trial of childhood non-Hodgkin's lymphoma (NHL), randomizing 256 patients to one of two treatment regimens. A 4-drug regimen (regimen 1, modified cyclophosphamide, Oncorin [vincristine], methotrexate, prednisone [COMP] ) was compared with a 10-drug regimen (regimen 2, modified LSA2-L2). Using the Rappaport classification, the review pathologist diagnosed the 213 evaluable tissue specimens as follows: lymphoblastic (LC), 73; Burkitt's tumor (BT), 40; "undifferentiated" non-Burkitt's type (NB), 67; large cell or "histiocytic" lymphoma (HI), 29; and other types (OT), 4. Concurrence in classification between the review and institutional pathologists was poor when using the above four categories; however, concurrence was 88% between the review pathologist and other hematopathologists, and 99% when classifying the specimens as lymphoblastic or nonlymphoblastic. For patients with nonlocalized disease, this randomized controlled study demonstrated a new important correlation of histopathology with the effectiveness of treatment. When analyzed without stratification into lymphoblastic and nonlymphoblastic types, the two regimens showed identical relapse free survival (RFS) curves for patients with nonlocalized involvement. However, when patients were stratified according to histologic classification, regimen 2 was superior to regimen 1 for patients with lymphoblastic lymphoma, achieving 74% RFS at 30 months compared to 31% for regimen 1 (P = 0.001). Conversely, those with nonlymphoblastic types (BT, NB, HI) treated with regimen 1 had a 58% RFS at 30 months compared to 32% for those treated on regimen 2 (P = 0.01). This study demonstrates that proper, routine histopathologic classification of NHL is the best criterion for choice of therapy in children with nonlocalized involvement. As a result of this study, all patients with nonlocalized disease, diagnosed after August 1980, were no longer randomized but were assigned to the appropriate treatment regimen based on prospective review of histopathology.

Childhood non-Hodgkin's lymphoma. The results of a randomized therapeutic trial comparing a 4-drug regimen (COMP) with a 10-drug regimen (LSA2-L2)

Members of the Childrens Cancer Study Group treated 234 eligible patients in a randomized trial designed to study the relative effectiveness of two therapy programs for the treatment of childhood and adolescent non-Hodgkin's lymphoma. Two chemotherapeutic strategies were compared: a 4-drug regimen (COMP) and a 10-drug regimen (modified LSA2-L2). Failure-free survival for all patients was 60 per cent at 24 months. In patients with disseminated disease treatment success was influenced by both the histologic subtype of disease and the therapeutic regimen followed. The 10-drug program was more effective than the 4-drug program in patients with disseminated lymphoblastic disease (two-year failure-free survival rate, 76 vs. 26 per cent, respectively; P = 0.0002), whereas the 4-drug program was more effective than the 10-drug program in those with nonlymphoblastic disease (57 vs. 28 per cent, respectively, P = 0.008). The less toxic, more easily administered 4-drug regimen was as effective as the 10-drug regimen in patients with localized disease (89 vs. 84 per cent, respectively).

Lymphoblastic lymphoma: late relapse in childhood

This report describes two children with lymphoblastic lymphoma who relapsed more than 2 1/2 years from diagnosis. Relapses occurred at seven and 20 months after completion of treatment. Their therapy consisted of an intensive pulse chemotherapy program combined with radiation therapy. Initial relapse after two years' treatment has been extremely rare in patients receiving contemporary chemotherapy programs, and two-year survival without disease has been considered a cure. These cases illustrate that late relapses can occur after intensive chemotherapy and that two-year disease-free survival must not be interpreted as a complete cure.

The long-term outlook for children treated for non-Hodgkin lymphomas. A report of the Children's Solid Tumour Group

Twentynine children with non-Hodgkin's lymphomas (NHL) were treated between 1974 and 1977 with a protocol based on those used for childhood ALL. 76% of patients had advanced disease by Ann Arbor criteria. All tumours had Rappaport's diffuse histology. 19 patients (65%) achieved complete remission, 14 (65%) remained alive and disease free beyond 42 months from diagnosis. 10 patients failed to enter complete remission, of whom all died. 7 patients relapsed; 5 died, 2 remain disease free and off treatment at 19 and 29 months. Comparison with a historic group of 20 consecutively treated children shows improved survival (P less than 0.01). 18 controls died. Histology was reviewed using the Kiel classification and staging according to Murphy's criteria. These are compared with the methods used initially. The improved outlook for children with NHL using intensive multiple drug regimes and cranial prophylaxis is confirmed. In staging childhood NHL, Murphy's criteria, which take into account the natural history of the disease, have greater prognosis value. Histology and pattern of outcome of the disease suggest basic differences between primary abdominal and primary mediastinal and nodal disease. This is now being confirmed with immunological typing and will be reflected in the development of future protocols.

Non-Hodgkin's lymphoma in children: results of treatment with the modified LSA2-L2 protocol

From June 1976 to May 1980, 25 previously untreated children with non-Hodgkin's lymphoma (NHL) were studied and treated with a protocol modified from the one (LSA2L2) proposed by Wollner [8]. Stage III and IV had, in addition, prophylactic treatment of the central nervous system (CNS) with cranial irradiation (2,400 rad plus intrathecal methotrexate). The complete remission rate is 96%. Of these patients, 76% are disease free surviving after a median observation time of nearly two years. The disease-free actuarial survival is 100% for 6 children with Stage I-II disease and 68% for 19 Stage III-IV children after median observations times respectively 25 + and 19 + months. None of the 19 high-risk patients developed CNS disease after prophylactic treatment. Mediastinal involvement and leukemia conversion at diagnosis were not unfavorable prognostic factors, but primary skeletal or subcutaneous disease and Burkitt-tupe histology were ominous features in patients treated by this regimen. It is concluded that good results are obtained when an aggressive multimodal and multiple drug regimen like the LSA2-L2 is coupled with CNS prophylaxis and is used assiduously to maintain complete remission during the first 12 months of treatment.

A randomized trial of combined modality therapy of childhood non-Hodgkin's lymphoma

From 1975 to 1978, 69 children with non-Hodgkin's lymphoma were staged and treated in a randomized protocol to determine the contribution of involved-field radiotherapy (IF-RT) to an effective drug regimen in Stages III-IV and the efficacy of prophylactic treatment of the central nervous system with cranial irradiation and intrathecal methotrexate in Stage II-IV. Induction therapy for Stages I-II was vincristine, prednisone, cyclophosphamide and IF-RT (3000-3500 rad). Stages III-IV received the same three drugs plus adriamycin, and were randomized to received or not receive IF-RT. The complete remission rate was 88%. After randomization to receive CNS prophylaxis or not, all children received oral mercaptopurine and methotrexate for 18 months. The two-year actuarial estimate of disease-free survival for all responders is 55% and is significantly influenced by stage. (Ninety percent disease-free survival for Stages I-II, versus 38.8% for III-IV, P less than .05). We observed no benefit but added toxicity from IF-RT in Stages III-IV. Efforts at CNS prophylaxis in high-risk children are warranted, since only 1 of 18 children randomized to receive prophylaxis developed CNS disease as the site of first relapse, whereas 4 of 16 receiving no prophylaxis did so.

A new therapy schedule for pediatric non-Hodgkin lymphoma toxicity with preliminary results

A pilot study of the toxicity and efficacy of a new treatment schedule for childhood non-Hodgkin's lymphoma was conducted by members of the Children's Cancer Study Group (CCSG) prior to its use in a randomized phase III trial. Chemotherapeutic agents used were cyclophosphamide (CPM), vincristine (VCR), and prednisone, together with intravenous (IV) and intrathecal methotrexate (IT MTS). Radiation therapy was also employed. From September 1976 to April 1977, 27 eligible, newly diagnosed patients with non-Hodgkin's lymphoma were entered onto this pilot study. Toxicity was acceptable with minor adjustments in dosage and timing of the myelosuppressive agents. Fourteen of the 22 patients entered onto maintenance remain entirely disease-free, and all have completed the prescribed course of chemotherapy. None of the 12 patients characterized as having a "favorable" prognosis has relapsed, with a median follow-up of 27 months from on study.