OCS: Childhood Cancer in Africa: a discussion.

Developments in the diagnosis and treatment of retinoblastoma have produced one of the greatest oncology success stories of the past 50 years in the developed world, but established retinoblastoma care for children in Sub-Saharan Africa remains virtually non-existent.

However, simple improvements could increase the success of treatment in this developing region of the world, where resources are scarce and poverty widespread.

Introduction.

In recent years, the AIDS pandemic has dominated efforts to improve health care provision in developing countries. However, World Health Organisation figures issued for 2005 show that, whilst AIDS, tuberculosis and malaria combined cause a total of 6.2 million deaths annually around the world, cancer alone kills 7 million people each year - the vast majority of these deaths occurring in developing nations.

Across Africa, infectious diseases and malnutrition have long been the primary cause of mortality and morbidity, but improved health care and extensive national immunisation programmes, mean that cancer diagnoses will continue to rise and account for a significant percentage of childhood illness and death.

Forty-two percent of Africans are under 15 of age, compared to just seventeen percent in developed countries. As Retinoblastoma is a cancer of early childhood, it’s diagnosis and treatment in Africa should be of significant concern to the global retinoblastoma community. Additionally, the hereditary nature of this cancer frequently devastates families on the continent, where women give birth to an average of 5.1 children, compared to just 1.6 children in developed nations.

CANCER Registries.

Many African countries have established tumour registries during the past decade. Whereas central nervous system tumours and leukaemia predominate in industrialised countries, across Africa, lymphomas and retinoblastoma - rare in the western world - take their place. However, widespread inability to effectively diagnose cancers of the central nervous system, and local tumour registry recording strategies probably distort these statistics to some extent.

Tanzania’s retinoblastoma experience is typical. This cancer accounted for 11.1% of childhood malignancies between 1973 and 1995, ranking it the fifth most common childhood cancer overall. Retinoblastoma was recorded as the most common malignancy (27.3%) below the age of five years.

The incidence of retinoblastoma is likely to increase in proportion to the number of children now surviving infancy due to improved post-natal care. In addition, as retinoblastoma occurs in a hereditary form, this cancer can be particularly devastating to affected families, on a continent where large families dominate.

These unique and changing epidemiological patterns across Africa offer important opportunities for research. However, only a small proportion of children with retinoblastoma are ever seen at modern health care centres that keep records of cancer diagnoses. In addition, many of these centres only record cases with a histology diagnosis. Obvious clinical presentations such as retinoblastoma are usually treated without laboratory analysis due to the lack of financial resources. Also excluded from most registries are children who die before diagnosis, those who are treated on specialist medical wards such as neurology and ophthalmology, or who are referred outside their country for treatment.

Therefore, statistical data about retinoblastoma is inconsistent and incomplete across the continent, leading to a lack of comprehensive knowledge about diagnosis, treatment and survival of the disease in Africa.

The World RB Registry presents an important opportunity to understand global impact of this rare disease. The Registry does not require expensive or sophisticated tools locally, and provides a golden opportunity for medics in all countries to become involved in collaborative research. All entries are recoded through the Internet, with the only requirement being ethics approval for participation from the local centre.

Pan-African participation in The World RB registry will help to achieve a full understanding of retinoblastoma patterns across the continent, to assess access to care, the response to available therapies in a variety of ethnic and socio-economic groups, and to empower appropriate application of resources.

Diagnosis and Treatment.

More than 95% of youngsters treated for retinoblastoma at paediatric cancer centres in the developed world are cured, and the success rates are continually rising. In contrast, the vast majority of an estimated 9,000 children who develop Rb each year around the world will die. Even in South Africa, where paediatric oncology care is comprehensive and of high quality, five year survival rates still hover precariously around 50%.

The majority of retinoblastoma children across Africa are diagnosed at an advanced stage, and many more may go undiagnosed. In South Africa, the Tygerburg Children’s Tumour Registry has consistently recorded a high number of advanced retinoblastoma diagnoses among black children from poor socio-economic backgrounds, compared with children from white, middle-class families. Widespread illiteracy, the principal use of traditional medicine, limitations of locally available primary health care services and cultural practices, such as the preferential care for children of a particular gender, all add to delayed and missed diagnoses across the continent.

Another barrier to diagnosis relates to the main symptom, leukocoria. This "cats eye reflex" is most detectable in artificial lighting or flash photography, and as both are rarities in rural African communities, most families remain unaware of signs until the cancer has advanced to a stage where the child's chances of cure are minimal.

Most children displaying signs of retinoblastoma are first seen at rural health care centres. These centres are generally run by caring, but inadequately trained and over-worked staff, dramatically affecting diagnostic accuracy. Consultation times average 1-3 minutes, and information is often missing from Out-Patient Department cards. Furthermore, lab support for rural health centres is rare, whilst expensive and time-consuming referrals to a regional hospital are routinely avoided.

Early recognition of Retinoblastoma dramatically improves the chances of vision-preserving cure, and reduces the cost of therapy. However, this can only be achieved if primary health care workers are trained to identify and refer suspect cases to appropriately trained doctors in a designated retinoblastoma treatment centres.

Currently, there are no comprehensive retinoblastoma treatment centres between Cape Town and Cairo - though treatment centres do exist in these two cities. In 1994, a survey of 20 African countries, carried out by the International Society of Paediatric Oncology, identified South Africa as the only country whose government health service could ensure essential diagnostic tests, standard therapies, and supportive care to all children diagnosed with Retinoblastoma, regardless of their location or socio-economic status.

The survey also established that seven of the twenty countries could provide neither CT nor MRI technology - necessary for diagnosis and follow up of Retinoblastoma, and standard external beam radiotherapy was not available in 8 countries. Adequate and reliable supplies of basic cytotoxic drugs were not available in 11 countries, and essential antibiotics were not available in 10. In some instances, countries were able to administer chemotherapy, but the absence of antibiotics to treat infection during therapy proved fatal in immune-compromised patients. Blood products for transfusion, also essential during cytotoxic therapy, were not available in 10 countries, and comprehensive nutritional provision was only available in South Africa.

One of Africa's greatest success stories in this field has occurred in Kenya, where efforts have been made to overcome fatalistic attitudes and rationalise patient care. In 1986, a 30 bed paediatric oncology unit opened at Kenyatta National Hospital in Nairobi. Although it does not accommodate all childhood cancer patients referred to KNH, the unit has gone a long way towards rationalising, centralising and integrating paediatric cancer care in East Africa today. The ultimate goal of its founders is to decentralise patient care by providing greater resources for provincial treatment facilities, and establishing specialist cancer units for the treatment of specific malignancies.

With limited resources in every country in Sub-Saharan Africa excluding South Africa, cancer patients have to be stratified to prioritise those with a reasonable chance of cure. A large proportion of Retinoblastoma diagnoses involve spread beyond the eye, and as these children have virtually no chance of cure with locally available resources, they are routinely managed with purely palliative therapy from the start.

Many medics are also forced to question the merits of treating a patient who will subsequently be incapable of caring for himself in a society where self-support is essential for survival. Retinoblastoma with bilateral enucleation is a prime example of this. In the absence of chemotherapy drugs, radiotherapy and focal therapy resources in many countries, enucleation of affected eyes remains the primary treatment across Africa.

A common problem leading to failure of therapy in curable patients is the interruption of treatment due to the financial burden of mounting transport and accommodation costs. Development of dedicated accommodation facilities linked to major treatment centres, and support structures to assist families with their travel costs would help to ensure a family's ability to comply with treatment schedules throughout their course.

Recurrence of Retinoblastoma is common, though this can be successfully treated when diagnosed early. Therefore, parents and health care clinic workers need to be educated about the importance of follow-up, to ensure that children who show an initially good response to therapy are not lost to recurrence because they are not monitored by specialists.

Cure of the majority of patients with retinoblastoma can only be achieved if parents and local health centre staff are educated about this cancer and the importance of early medical intervention, if properly trained staff apply current knowledge, and if appropriate resources are available for diagnosis and treatment.

Conclusion.

Epidemiological data about retinoblastoma in Africa is limited. When allocating funding, health care policymakers are greatly influenced by statistics illustrating incidence and treatment patterns. The international retinoblastoma community can further the cause of children with retinoblastoma in Africa by generating and sharing such data. Therefore, an important first priority for this continent is participation in the World Rb Registry, a feasible project that only requires internet access,

Increased awareness of this cancer among rural health care workers is also essential, whilst the financial and pharmacological obstacles to treatment must be anticipated and solved.

Though survival rates are consistently much lower than in the developed world, it is clear from existing cancer registry data that children with retinoblastoma in Africa can be cured with current treatment protocols when diagnosed early. The hurdles are great, but it is entirely possible to work towards a day when no child faces death in Africa from a completely treatable cancer such as retinoblastoma..