Non-Hodgkin lymphoma in children: a 20-year population-based epidemiologic study in western Sweden

Profile of Childhood Non-Hodgkin Lymphomas at a Tertiary Care Hospital

Context: Lymphoma was the second most common malignancy accounted for 22% of pediatric cases, of which 34 (68%) were non-Hodgkin’s lymphoma (NHL). Aims: To find the incidence, clinical presentations, laboratory findings, proportion of extranodal involvement, and to study histological subtypes (REAL/WHO classification) of NHL, compare them with reported case series in the world literature. Settings and Design: Gross specimens and biopsies of pediatric NHL were retrieved from the Department of Surgical Pathology from the year 2004 to 2013 at a tertiary care hospital. Patients and Methods: Gross and microscopy of incisional biopsies and surgically resected specimens of pediatric cases were studied using hematoxylin and eosin stain and wherever needed special stain and immunohistochemistry were used. Results: The incidence of NHL was higher in more than 10 years of age group with male predominance. Burkitt’s lymphoma (BL) (41.2%) was the most common subtype followed by T-lymphoblastic lymphoma (T-LL) (29.4%). Predominantly extranodal presentation was seen, BL presented as ileocecal masses (five cases) and orbital swelling (three cases). T-LL presented as a mediastinal masses (six cases). Rare cases of precursor B-LL involving orbital mass and plasmablastic lymphoma involving paranasal sinuses were studied. Among bone marrows studied a case of T-LL developed pancytopenia, during chemotherapy showed giant pronormoblast (Parvovirus infection). HIV association was seen in five cases of NHL. Postchemotherapy disease-free survival was very low and many patients died during chemotherapy. Conclusion: Although the incidence of HL is higher in children, in the present study, NHL with extranodal presentation (58%) involving rare sites with poor prognosis is higher, 15% of all cases showed HIV seropositivity.

Stage at diagnosis for children with blood cancers in Australia: Application of the Toronto Paediatric Cancer Stage Guidelines in a population-based national childhood cancer registry

BACKGROUND

Information on stage at diagnosis for childhood blood cancers is essential for surveillance but is not available on a population basis in most countries. Our aim was to apply the internationally endorsed Toronto Paediatric Cancer Stage Guidelines to children (<15 years) with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), Hodgkin lymphoma (HL), or non-Hodgkin lymphoma (NHL) and to assess differences in survival by stage at diagnosis.

PROCEDURE

Stage was defined by extent of involvement of the central nervous system (CNS) for ALL and AML and using the Ann Arbor and St Jude-Murphy systems for HL and NHL, respectively. The study cohort was drawn from the population-based Australian Childhood Cancer Registry, consisting of children diagnosed with one of these four blood cancers between 2006 and 2014 with follow-up to 2015. Five-year observed survival was estimated from the Kaplan-Meier method.

RESULTS

Stage was assigned to 2201 of 2351 eligible patients (94%), ranging from 85% for AML to 95% for ALL, HL, and NHL. Survival following ALL varied from 94% (95% CI = 93%-95%) for CNS1 disease to 89% (95% CI = 79%-94%) for CNS2 (P = 0.07), whereas for AML there was essentially no difference in survival between CNS^- (77%) and CNS⁺ disease (78%; P = 0.94). Nearly all children with HL survived for five years. There was a trend (P = 0.04) toward worsening survival with higher stage for NHL.

CONCLUSIONS

These results provide the first population-wide picture of the distribution and outcomes for childhood blood cancers in Australia by extent of disease at diagnosis and provide a baseline for future comparisons.

Hepatic late adverse effects after antineoplastic treatment for childhood cancer

BACKGROUND

Survival rates have greatly improved as a result of more effective treatments for childhood cancer. Unfortunately, the improved prognosis has been accompanied by the occurrence of late, treatment-related complications. Liver complications are common during and soon after treatment for childhood cancer. However, among long-term childhood cancer survivors, the risk of hepatic late adverse effects is largely unknown. To make informed decisions about future cancer treatment and follow-up policies, it is important to know the risk of, and associated risk factors for, hepatic late adverse effects. This review is an update of a previously published Cochrane review.

OBJECTIVES

To evaluate all the existing evidence on the association between antineoplastic treatment (that is, chemotherapy, radiotherapy involving the liver, surgery involving the liver and BMT) for childhood cancer and hepatic late adverse effects.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2018, Issue 1), MEDLINE (1966 to January 2018) and Embase (1980 to January 2018). In addition, we searched reference lists of relevant articles and scanned the conference proceedings of the International Society of Paediatric Oncology (SIOP) (from 2005 to 2017) and American Society of Pediatric Hematology/Oncology (ASPHO) (from 2013 to 2018) electronically.

SELECTION CRITERIA

All studies, except case reports, case series, and studies including fewer than 10 patients that examined the association between antineoplastic treatment for childhood cancer (aged 18 years or less at diagnosis) and hepatic late adverse effects (one year or more after the end of treatment).

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection and 'risk of bias' assessment. The 'risk of bias' assessment was based on earlier checklists for observational studies. For the original version of the review, two review authors independently performed data extraction. For the update of the review, the data extraction was performed by one reviewer and checked by another reviewer.

MAIN RESULTS

Thirteen new studies were identified for the update of this review. In total, we included 33 cohort studies including 7876 participants investigating hepatic late adverse effects after antineoplastic treatment (especially chemotherapy and radiotherapy) for different types of childhood cancer, both haematological and solid malignancies. All studies had methodological limitations. The prevalence of hepatic late adverse effects, all defined in a biochemical way, varied widely, between 0% and 84.2%. Selecting studies where the outcome of hepatic late adverse effects was well-defined as alanine aminotransferase (ALT) above the upper limit of normal, indicating cellular liver injury, resulted in eight studies. In this subgroup, the prevalence of hepatic late adverse effects ranged from 5.8% to 52.8%, with median follow-up durations varying from three to 23 years since cancer diagnosis in studies that reported the median follow-up duration. A more stringent selection process using the outcome definition of ALT as above twice the upper limit of normal, resulted in five studies, with a prevalence ranging from 0.9% to 44.8%. One study investigated biliary tract injury, defined as gamma-glutamyltransferase (γGT) above the upper limit of normal and above twice the upper limit of normal and reported a prevalence of 5.3% and 0.9%, respectively. Three studies investigated disturbance in biliary function, defined as bilirubin above the upper limit of normal and reported prevalences ranging from 0% to 8.7%. Two studies showed that treatment with radiotherapy involving the liver (especially after a high percentage of the liver irradiated), higher BMI, and longer follow-up time or older age at evaluation increased the risk of cellular liver injury in multivariable analyses. In addition, there was some suggestion that busulfan, thioguanine, hepatic surgery, chronic viral hepatitis C, metabolic syndrome, use of statins, non-Hispanic white ethnicity, and higher alcohol intake (> 14 units per week) increase the risk of cellular liver injury in multivariable analyses. Chronic viral hepatitis was shown to increase the risk of cellular liver injury in six univariable analyses as well. Moreover, one study showed that treatment with radiotherapy involving the liver, higher BMI, higher alcohol intake (> 14 units per week), longer follow-up time, and older age at cancer diagnosis increased the risk of biliary tract injury in a multivariable analysis.

AUTHORS' CONCLUSIONS

The prevalence of hepatic late adverse effects among studies with an adequate outcome definition varied considerably from 1% to 53%. Evidence suggests that radiotherapy involving the liver, higher BMI, chronic viral hepatitis and longer follow-up time or older age at follow-up increase the risk of hepatic late adverse effects. In addition, there may be a suggestion that busulfan, thioguanine, hepatic surgery, higher alcohol intake (>14 units per week), metabolic syndrome, use of statins, non-Hispanic white ethnicity, and older age at cancer diagnosis increase the risk of hepatic late adverse effects. High-quality studies are needed to evaluate the effects of different therapy doses, time trends, and associated risk factors after antineoplastic treatment for childhood cancer.

Pediatric non-Hodgkin lymphomas: first report from Central Africa

BACKGROUND

Information on presentation and outcome of pediatric non-Hodgkin's lymphoma is limited from Africa. The demographic characteristics, distribution of different subtypes were noted and compared with published reports from other parts of the world.

METHODS

The study was conducted in Kinshasa, the Democratic Republic of Congo between January 2002 and December 2012.

RESULTS

A total of 63 cases of pediatric non-Hodgkin's lymphoma were retrospectively analyzed. This cohort represents the largest series of pediatric non-Hodgkin's lymphoma presented from sub-Saharan Africa. Median age was 8.7±3.6 years. There were 43 (68.3%) males. A mean of 82 ± 59 days passed from detection of the first sign to referral to oncology unit. Morphology distribution showed that 42 cases (66.7%) had a diagnosis of Burkitt lymphoma, 16 cases (25.4%) had diffuse large B-cell lymphoma and 5 cases (7.9%) had NHL-not otherwise specified. The majority of patients (82.5%) had advanced stage (stage III and IV). Immunohistochemistry findings were available for 32 biopsy samples. All (100%) cases were B-cell non-Hodgkin's lymphoma and immunohistochemistry had identified 18 (56.3%) cases of Burkitt lymphoma. In our cohort, 22 of 32 cases expressed positive bcl-2 and 12 (37.5%) were found to be positive for bcl-6. Thirty-one (96.7%) cases were positive for high Ki-67 antigen expression. Assuming that cases lost to follow-up worsened and died, the mortality would be 98.4%.

CONCLUSION

In comparison to western data, we observed higher proportion of B-cell non-Hodgkin's lymphoma, Burkitt Lymphoma and patients with bcl-2 expression.

Hepatic late adverse effects after antineoplastic treatment for childhood cancer

BACKGROUND

Survival rates have greatly improved as a result of more effective treatments for childhood cancer. Unfortunately the improved prognosis has resulted in the occurrence of late, treatment-related complications. Liver complications are common during and soon after treatment for childhood cancer. However, among long-term childhood cancer survivors the risk of hepatic late adverse effects is largely unknown. To make informed decisions about future cancer treatment and follow-up policies it is important to know the risk of, and associated risk factors for, hepatic late adverse effects.

OBJECTIVES

To evaluate the existing evidence on the association between antineoplastic treatment for childhood cancer and hepatic late adverse effects.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 2), MEDLINE (1966 to June 2009) and EMBASE (1980 to June 2009). In addition, we searched reference lists of relevant articles and conference proceedings.

SELECTION CRITERIA

All studies except case reports, case series and studies including less than 10 patients that examined the association between antineoplastic treatment for childhood cancer (aged 18 years or less at diagnosis) and hepatic late adverse effects (one year or more after the end of treatment).

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We identified 20 cohort studies investigating hepatic late adverse effects after antineoplastic treatment for childhood cancer. All studies had methodological limitations. The prevalence of hepatic late adverse effects varied widely, between 0% and 84.2%. Selecting studies where the outcome of hepatic late adverse effects was well defined as alanine aminotransferase (ALT) above the upper limit of normal resulted in five studies. In this subgroup the prevalence of hepatic late adverse effects ranged from 8.0% to 52.8%, with follow-up durations varying from one to 27 years after the end of treatment. A more stringent selection process using the outcome definition of ALT as above twice the upper limit of normal resulted in three studies, with a prevalence ranging from 7.9% to 44.8%. Chronic viral hepatitis was identified as a risk factor for hepatic late adverse effects in univariate analyses. It is unclear which specific antineoplastic treatments increase the risk of hepatic late adverse effects

AUTHORS' CONCLUSIONS

The prevalence of hepatic late adverse effects ranged from 7.9% to 52.8% when selecting studies with an adequate outcome definition. It has not been established which childhood cancer treatments result in hepatic late adverse effects. There is a suggestion that chronic viral hepatitis increases the risk of hepatic late adverse effects. More well-designed studies are needed to reliably evaluate the prevalence of, and risk factors for, hepatic late adverse effects after antineoplastic treatment for childhood cancer.

Infant anaplastic lymphoma: case report and review of the literature

Anaplastic large cell lymphoma (ALCL) is a well-known entity, but there are no data on prognosis according to the age of the patient, especially in infants. A 2-month-old girl was admitted with a 2-week history of coughing, fever, and lymphadenopathy. Physical examination revealed mild respiratory distress, an erythematous macular rash on her trunk, massive cervical lymphadenopathy, splenomegaly, and very mild ascites. Chest radiograph showed bilateral pulmonary infiltrates, pleural effusion, and a mediastinal mass. CBC count showed WBC: 172,000/microL (PMN 40%, lymphocytes 47%, monocytes 3%); hemoglobin concentration: 8.7 g/dL; platelets: 390,000/microL. Cervical lymph node biopsy revealed anaplastic lymphoma with positive staining to ALK 1 and TIA 1. Immunophenotypic analysis of peripheral and bone marrow lymphoid cells showed an aberrant T-cell immunophenotype, including expression of CD3, CD45R0+, CD43+, and CD30+. Cytogenetic analysis performed on blood and bone marrow samples demonstrated the translocation t(2;5) (p23;q35), and trisomy 47. After leucophoresis, the child received chemotherapy according to the ALCL-99-EICNHL protocol, and was started on corticosteroids and cyclophosphamide, which resulted in marked improvement. After the second course, WBC decreased to 6000/microL without tumor lysis syndrome, but the child developed bacterial and fungal disseminated infections and died of septic shock with multiorgan failure. This report is of a rare case of infant anaplastic lymphoma and excellent response to treatment. Unfortunately, she did succumb to overwhelming infection. More reports of similar cases may determine the cause and prognosis of such children, helping to tailor therapy according to the age of the child and other prognostic factors, especially bone marrow involvement.

Report of an International Network of Cancer Treatment and Research workshop on non-Hodgkin's lymphoma in developing countries

The International Network of Cancer Treatment and Research (INCTR) recently organized a workshop on non-Hodgkin lymphomas (NHLs) in selected developing countries with the purpose of examining existing information relating to the pathology and management of these neoplasms, and identifying potential areas for research. This report provides a summary of the information presented and is focused primarily on the pathology of NHLs in children and adults. In most countries, the WHO classification of lymphomas was used and most participating centers included immunohistochemistry using a wide array of lymphoid antibodies as part of routine diagnosis. Some of the series had been reviewed by an external panel of experts. B-cell lymphomas accounted for 82-88% of all NHLs. The proportions of chronic lymphatic leukemia (4-6%), mantle cell lymphoma (MCL, 3-5%), and plasmacytoma (2-4%) were similar in the series presented. However, there was a significant variation in the proportion of follicular lymphoma (FL), which accounted for 15% and 11% in India and Kuwait, but less than 5% in Pakistan and Egypt. All of these frequencies are significantly lower than those reported in Western series. Diffuse large B-cell lymphoma accounted for about 35% of cases in India but for more 50% in other countries, but this difference was not accounted for by an increased incidence in a single lymphoma subtype in India, but rather an apparent paucity of several subtypes (such as mantle cell and marginal zone lymphomas (MZL)) in other series. There were relatively high frequencies of Burkitt lymphoma in Egypt (7%) and precursor T-cell lymphoblastic lymphoma in India (6-7%). Peripheral T-cell lymphomas (PTCLs) (not otherwise specified and angioimmunoblastic subtypes) accounted for 3-5% of NHLs, and extranodal lymphoma of T/NK cell type was rare (<1%). These differences in the relative proportions of NHL subtypes among developing countries and between developing countries and the rest of the world presumably arise from differences in environmental and genetic factors that influence lymphomagenesis and strongly suggest that more research in developing countries would provide valuable insights into the pathogenesis of lymphoid neoplasms.

Use of the World Health Organization (WHO) classification of non-Hodgkin's lymphoma in Mumbai, India: a review of 200 consecutive cases by a panel of five expert hematopathologists

This study aims to answer the question whether the World Health Organization (WHO) classification of non-Hodgkin's lymphoma (NHL) can be practised to international standards at the Lymphoma Registry (LR) established at the Tata Memorial Hospital, Mumbai, India. Furthermore, the study aims to identify differences in the distribution of NHL subtypes at this LR (likely to be representative of India) as compared to the rest of the world. A panel of 5 expert hematopathologists from the NHL Classification Project reviewed 200 consecutive NHL cases at the LR in January of 2001. These cases were accrued during August and September, 2000. On all cases, hematoxylin and eosin stains and appropriate immunostains were available for review. The diagnosis made by the host pathologist at the LR (KNN) and the initial diagnosis made by each of the expert hematopathologists was compared with the consensus diagnosis. A consensus diagnosis was made by the 5 experts in 197 cases. The agreement of the host pathologist with the consensus diagnosis was 82% and the agreement of the individual experts with the consensus diagnosis varied from 76-88% (mean 82%). According to the consensus diagnosis, 80% of NHLs were of B-cell type, 18% were of T-cell type, and the immunophenotype could not be determined in the remaining 2% of cases. In conclusion, the WHO classification of NHL was properly utilized at the Lymphoma Registry, Mumbai, India, and geographic differences were noted in the distribution of NHL subtypes at the LR as compared to the rest of the world. Precursor T lymphoblastic leukemia/lymphoma was more common in India (7%) than the rest of the world (1-4%), and indolent B-cell NHLs (29%) were less common than in the West. As compared to China and Japan, peripheral T-cell lymphoma (4.6%), extranodal NK/T cell lymphoma, nasal type (0.5%) and extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT-lymphoma) (2.6%) were less common, but follicular lymphoma (15%) and chronic lymphocytic leukemia/small lymphocytic lymphoma (5%) were more common. This suggests that the distribution of the B-cell and T-cell lymphomas in the Indian population, except for lymphoblastic lymphoma, lies in between the Western world (mainly Caucasian) and the Orientals.

Increasing incidence rates of childhood malignant diseases in Sweden during the period 1960–1998

We analysed the trends in incidence rates of childhood cancer in Sweden. All cases of malignant diseases and benign brain tumours in children, 0-14 years old, reported to the Swedish Cancer Registry 1960 to 1998 were included, n=9298. Cases were classified according to the International Classification of Childhood Cancer. Average annual change in incidence rate was calculated to +1.01%, (95% confidence interval CI=0.80, 1.22). An increase in incidence rate per year was found for leukaemia, +0.85% (95% CI=0.42, 1.28), lymphomas +1.87% (95% CI=1.17, 2.58), CNS (central nervous system) tumours +1.45% (95% CI=1.02, 1.88), sympathetic nervous system tumours +1.61% (95% CI=0.79, 2.44), hepatic tumours +2.62% (95% CI=2.02, 3.21), and germ cell and gonadal tumours +1.21% (95% CI=0.23, 2.19). Of the CNS tumours, significant changes were seen for low-grade glioma/astrocytoma +2.10% (95% CI=1.41, 2.80), benign brain tumours +3.77% (95% CI=2.47, 5.10), and PNET/medulloblastoma +1.96% (95% CI=0.48, 3.46). Changes in diagnostic criteria and better diagnostic tools may have contributed to these results.

Non-radiolabelled PCR consensus primers and automatic sequencing enable rapid identification of tumor-specific V(H) CDR3 in aggressive B-cell malignancies

Even though the results of current therapy are improved for B-cell acute lymphoblastic leukemia (B-ALL) and Burkitt's lymphoma (BL), prognosis of relapsed mature B-ALL and BL still remain extremely poor. In this study, we investigated the possibility of applying the use of non-radiolabelled PCR consensus primers and automatic sequencing for the rapid identification of the tumor-specific V(H) CDR3 nucleotide sequence, in mature B-ALL and BL. RNA was extracted from four consecutive, unselected samples from BL cases and three consecutive, unselected samples from mature B-ALL cases. The feasibility of the identification of the tumor-specific V(H) CDR3 nucleotide sequence was then assessed by using non-radiolabelled PCR consensus primers with automatic sequencing. The tumor-specific V(H) CDR3 nucleotide sequence was successfully identified for all seven patients (3 mature B-ALL and BL). The time required was substantially lower than that of the other methods previously published, despite the poor quality of some of the samples. The procedure showed rapidity, reliability and reproducibility. The characteristics of the methodology applied widen the possibility of developing anti-idiotypic therapeutic strategies, even in these B-cell malignancies.

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.

Clinical characteristics and treatment results of LMB/LMT regimen in children with non-Hodgkin's lymphoma

Lymphomas are the second most common cancers after leukemias seen in children in Turkey, although they rank third in many western countries. Ninety-seven patients with newly diagnosed, untreated non-Hodgkin's lymphoma, between April 1994 and December 1997, were included in this study. Modified lymphoma malign B (LMB) and lymphoma malign T (LMT) regimens were used for treatment of B- and T-cell disease, respectively. Ten (10.3%), 68 (70.1%), and 19 (19.6%) patients had stage II, III, and IV disease, respectively. Forty-eight, 19, 15, 9, 5, and 1 patients had tumors at abdominal, mediastinal, disseminated, head and neck, extranodal, and peripheral nodal locations, respectively. Seventy-two patients were treated with LMB89 regimen and 25 were treated with LMT89 regimen. Thirty-four patients had tumor lysis at diagnosis, and 9 patients required dialysis. Objective response rates were 75% for patients treated by LMB regimen and 92% for those treated by LMT regimen. Two-year overall survival rates were 90, 66.1, and 50.8% for patients with stage II, III, and IV disease, respectively. Two-year overall survival rates were 64.2% for LMB-treated patients and 70.8% for LMT-treated patients. Poor response at the end of cytoreductive treatment and age younger than 4 years were poor prognostic factors. Pediatric lymphomas could be treated safely and effectively by LMB and LMT regimens.

A population-based study of pediatric anaplastic large cell lymphoma

BACKGROUND

Anaplastic large cell lymphoma (ALCL) is a relatively rare form of non-Hodgkin lymphoma (NHL) in children constituting 10-15% of this entity. To the authors' knowledge, there are no population-based pediatric studies in the literature, and incidence estimates have not been attempted.

METHODS

A population-based study of all children in British Columbia, Canada, younger than 15 years of age presenting between January 1988 and December 1999 with an immunohistologically confirmed diagnosis of CD30+ ALCL was completed. Demographic, ethnic, clinical, treatment, and outcome details were collected on all patients. Population figures were obtained from census data through the BC STATS.

RESULTS

Ten patients were identified and confirmed to have ALCL on the basis of morphology and immunohistochemical stains. This equates to an annual incidence of 1.2 per million children younger than 15 years of age. The mean age at diagnosis was 8.23 years with a range of 1.4-13.0 years. There was an overrepresentation of East and Southeast Asian patients (40%) in the ALCL group compared with other subtypes of NHL and the pediatric population of British Columbia. Twenty percent of the patients had evidence of central nervous system (CNS) disease at diagnosis.

CONCLUSIONS

The annual incidence of ALCL in children younger than 15 years of age in British Columbia is 1.2 per million. The overrepresentation of East and Southeast Asian ethnic origin remains unexplained. The rate of CNS involvement is much higher than that previously reported in large non-population-based series (0-3%). Although the low numbers do not allow firm conclusions, it would seem prudent to continue to investigate all newly diagnosed patients for CNS involvement in British Columbia.

Space-time clustering of childhood lymphatic leukaemias and non-Hodgkin's lymphomas in Sweden

BACKGROUND

The discussion concerning clusters of childhood leukaemia has mainly been focused on their relation to the time and place of diagnosis. Recently some studies have indicated clustering not only at diagnosis, but also around time and place of birth. Space-time clustering at time of birth could be of special interest if the aetiological agent is of infectious origin and the induction of leukaemia either occurs pre- or perinatally or an infection at that time favours a poor subsequent immune response to the agent.

METHODS

To identify possible space-time clustering we have used the close-pair method of Knox. One-thousand-twenty recorded cases (0-14 years) of childhood acute lymphatic leukaemia and 293 cases (0-14 years) of malignant non-Hodgkin's lymphoma from Sweden between 1973-1996 were analysed. The records include date of birth and of diagnosis as well as addresses at birth and at diagnosis.

RESULTS

A significant excess of case-pairs (25 observed, 14.9 expected, p = 0.01) was observed close in date and place of birth in the 4-14 year age group with acute lymphatic leukaemia (ALL). However there was no statistically significant clustering found around time of diagnosis. When the cases of leukaemia and the non-Hodgkin's lymphomas were combined no statistically significant clustering was obtained neither at birth nor at diagnosis.

CONCLUSIONS

This study strengthens the evidence of space-time clustering around the birth date in children whom later developed ALL. This observation is in support of the hypothesis that pre- or perinatal infections can induce a process leading to ALL.