Epidemiology of childhood cancer in Zaire

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.

The problem of pediatric malignancies in the developing world

In industralized countries, 70 to 80% of children with cancer can be cured by expensive interdisciplinary teamwork and by cooperation on the national or international level. As a result of poor socio-economic conditions, worldwide, less than 20% of the approximately 185,000 children developing cancer each year get adequate treatment. This is also true for 14 to 15 million children dying each year of diarrhea and infections, but while this number is decreasing, the number of children with cancer is increasing. In "middle income" developing countries, cancer is now a leading cause of death for children between 5 and 15 years of age. The "geography" of pediatric cancer reveals complex interactions between environment, lifestyle, and carcinogenesis. The "mapping" of pediatric cancer is far from complete, and the investigation of carcinogenetic interactions has barely started. A great challenge is the planning of pediatric oncology in developing countries. The goals are to improve the access to treatment and treatment results. Even if pediatric oncology has a low priority, the institution, in each country or large province, of at least one pediatric cancer unit may improve not only cancer treatment but medical care in general. By promoting education, organizing meetings, and setting minimum standards for training and care, international organizations can contribute to the development of pediatric oncology worldwide.

Malignant tumours in Omani children

In an effort to understand better the epidemiology of childhood cancer in Oman, a retrospective review of hospital-based biopsy-proven malignant tumours was undertaken. A total of 313 cases of malignant diseases in children between the ages of 0 and 12 years were diagnosed in Oman during the 5-year period from January 1988 to December 1992, inclusive. Leukaemias were the most commonly occurring malignancies (32.3%), followed by lymphomas (29%) and brain tumours (11.2%). The male:female ratio was 1.3:1. The commonest presenting age group was 2 years, the majority of which were leukaemias and lymphomas. Differences and similarities between Omani data and those from other countries are discussed.

Cancer and other causes of childhood mortality in Bombay, India

Mortality from cancer and other diseases from 1964 to 1984 and their contributions in 1984 to premature mortality in Bombay, India, were studied. Cancer was the ninth and tenth cause of death in boys and girls younger than 15 years of age, respectively, in 1984. Prematurity and infectious diseases contributed most to years of potential life lost by children younger than 5 years of age in 1984; cancer, heart disease, and accidents-injury became important in children older than 5 years. When currently high mortality rates in infants and children younger than 5 years of age are reduced, cancer may become a greater childhood health problem. Approximately 5% of male and 3% of female patients with cancer in six hospital and three population-based cancer registries in India were children younger than 15 years of age. Cancer mortality declined from the rate during 1964 to 1972 to the rate during 1973 to 1984 by about 40% in children younger than 5 years old and in girls of 10 to 14 years of age and by 7.5% and 14% in the 5 to 9-year-old boys and girls, respectively. It increased by 12% in the 10 to 14-year-old boys. Early diagnosis and treatment of cancer in children older than 5 years of age may yield increased productive person-years of life.

International variations in the incidence of childhood lymphomas

The International Agency for Research on Cancer has coordinated a worldwide study of childhood cancer incidence, with data provided by contributors from over 50 countries. We present here the results on lymphomas from this study and other sources. Hodgkin's disease had a relatively high incidence in North Africa and West Asia and a low incidence throughout East Asia. In populations of predominantly European origin, the highest rates tended to be in warmer countries of lower latitude. In industrialised Western countries, the incidence increased steeply with age and was low in childhood compared with that in young adults whereas elsewhere the increase in incidence between childhood and adults aged 20-34 was much less marked. The age-distribution of Hodgkin's disease in childhood appears to be related to levels of socio-economic development but the total incidence seems to be determined more by ethnic and environmental factors. The highest incidence of Burkitt's lymphoma occurred in tropical Africa and Papua New Guinea. Elsewhere, Burkitt's lymphoma was rare, though the incidence was higher in Spain, North Africa and the Middle East than in other areas. In most Western countries, a third of all non-Hodgkin lymphomas may be Burkitt's. There was no consistent pattern in the incidence of other non-Hodgkin lymphomas except for a tendency towards higher rates around the Mediterranean and in some Latin American registries.

Malignant tumors in children of northeastern Zaire. A comparison of distribution patterns

In an effort to better understand the epidemiology of cancer in Zaire, a retrospective review of biopsy-proven malignant tumors was undertaken. Of 188 biopsies taken from children aged 0-15 years over a 4.5 year period, 73 (39%) revealed malignancy. Fifty-six percent of patients with malignant tumors were boys. Lymphoma was the most common tumor (28 patients, 15 with Burkitt's Lymphoma). Sarcoma (15 patients), carcinoma (8 patients), Wilms' Tumor (6 patients), and retinoblastoma (5 patients) were also seen. Lymphomas were most heavily represented in the first 5 years of life, while sarcoma and carcinoma accounted for most of the malignancies in children after 10 years of age. Lymphomas and sarcomas are relatively more common in Zaire than in North America and Europe, while leukemia and central nervous system tumors are notably less common in Zaire. In view of current limitations on health care in rural Zaire, cancer care should be directed toward early diagnosis, quick referral for appropriate surgical care, and use of the limited arsenal of chemotherapy.