viernes, 16 de marzo de 2012

Overcoming global cultural and financial disparities to treat children with cancer « NCI Benchmarks

Overcoming global cultural and financial disparities to treat children with cancer « NCI Benchmarks

Overcoming global cultural and financial disparities to treat children with cancer

African children
Children in resource poor countries are at high risk of dying from cancer
Major advances have been made in the treatment of childhood cancer but this progress predominately benefits patients who live in resource affluent, developed countries. In resource poor, developing nations, where 80 percent of all childhood cancers occur, the majority of youngsters with potentially treatable disease will die from lack of therapy.
Of all of the world’s developing countries, those in sub-Saharan Africa are among the poorest and its children at greatest risk. 
At the most basic level, the easiest way to increase survival rates in these children would be to train more doctors and nurses in their care and to add facilities where they can be adequately treated. To do this, cultural and financial disparities endemic to this population need to be addressed. Scientists at NCI are working with colleagues, including those at International Network for Cancer Treatment and Research (INCTR), toward this end.

Impact of poverty, social and cultural issues in developing countries

Patterns of childhood cancer

Recent reports indicate that in developing countries, 200,000 children are diagnosed with cancer each year but only about 25 percent of them survive. By contract, in developing countries, 50,000 children are diagnosed with cancer each year and 80 percent survive. For a better comparison, examining cancer rates (as opposed to cases) would allow for an ‘apples to apples’ analysis but those numbers are less reliable in developing countries.
Of all new cases of childhood cancer worldwide, approximately 40 percent are leukemias or lymphomas. In virtually every data registry available worldwide, with the exception of sub-Saharan Africa, acute lymphoblastic leukemia, or ALL, is listed as the most common cancer in children.
In the United States, ALL is more common in white than in black children, but most common in Hispanics. The highest incidence rates worldwide are in Costa Rica, and other Latin American countries (e.g., Mexico City has the highest incidence of ALL in the world), Finland, Canada and Hong Kong.
While ALL incidence rates are high in developed countries, the pattern of cancer is very different in sub-Saharan Africa. Here, children have a high incidence of Kaposi sarcoma and Burkitt lymphoma, while cases of ALL are much less common.
Credit: INCTR
In developing countries, parents and caregivers of children with cancer may not have access to health clinics or money to pay for treatments. They may also have a limited understanding of their child’s disease and of risks and potential outcomes.
Social and psychological support may also be limited, or nonexistent, for a child with cancer. In countries where cancer is stigmatized and the patient rejected, a father’s perception weighs heavily on the medical treatment his child will receive. Since body image is also critical in many of these countries, a girl without an eye or other facial deformity (as a result of surgery) is not considered marriageable, and thus will be a burden to her family. So, acknowledgement of the child’s cancer, and the subsequent treatment of it, may be withheld.
Additionally, herbal remedies are often used or preferred in developing countries over drugs used in developing, or western countries, particularly in sub-Saharan Africa. This may be detrimental to treatment since many of these herbal remedies are often not well researched or are poorly regulated. Herbal remedies may also be combined with western drugs, creating the potential for harmful drug interactions for young patients.
Based on these factors, a child with cancer may receive a late diagnosis and their parents or caregiver may refuse treatment, stop treatment, or treat the child indiscriminately with herbal remedies.

Deficiencies in resources—professional and public health

Another concern in developing countries is that family doctors, pediatricians, and non-cancer specialists may not have the expertise to recognize and treat childhood cancers. Incorrect diagnoses of cancer are not uncommon since symptoms associated with cancer such as anemia, bruising, fever and swollen glands are also often found in more common conditions such as tuberculosis and malaria. The wrong diagnoses may cause children to receive inappropriate or inadequate care and therapy that may further weaken them.

Even if cancer is properly diagnosed in these children, they most likely will not have access to pediatric oncologists, surgeons (e.g., those that treat the eyes or bones), and radiotherapists who can effectively manage their care.
Many developing countries also lack a strong national policy for control of childhood cancer. Inaccurate cancer incidence and death statistics, few or incomplete cancer registries in rural areas, and a shortage of national clinical and laboratory research, further add to the disease burden of children in these nations.

NCI and the importance of regional research

Clinical trials in developed countries primarily address cancers common to their population, and do not fully address advanced cases of cancers, such as Burkitt lymphoma, which are found in children in developing countries, particularly those in sub-Saharan Africa. Also, since differences in disease biology, drug handling and co-morbidities occur in diverse ethnic groups and environments, treatment for this population of children may also vary.
To develop treatment protocols and support in resource poor countries, researchers at the NCI’s Office of HIV and AIDS Malignancies (OHAM) and INCTR are conducting various projects in specific areas of cancer control, with cancers in women and children having highest priority. In developing countries, women die unnecessarily from cancers and infectious diseases, such as HIV/AIDS, as well as from problems associated with pregnancy and childbirth. Safeguarding women’s health, while educating them on medical issues relative to them and their families, directly benefits the health and welfare of their children.

NCI-supported clinical trials in Africa— a Burkitt lymphoma case study

Dr. Trish Scanlan (red dress), volunteer, and young patients at pediatric cancer ward in Muhimbili National Hospital in Tanzania. Credit: Used with the permission of INCTR
Dr. Trish Scanlan (red dress), volunteer, and young patients at pediatric cancer ward in Muhimbili National Hospital in Tanzania. Credit: Used with the permission of INCTR
NCI has supported research by INCTR investigators who are conducting clinical trials of Burkitt lymphoma, including HIV positive Burkitt lymphoma in sub-Saharan Africa. Their goal is to improve both pathology services (diagnosis) in participating countries, and the survival rate, with a regimen suitable for children in resource poor settings with respect to toxicity and cost.
The team has conducted a large study of the treatment of Burkitt lymphoma in Tanzania, Uganda, Kenya, Democratic Republic of Congo and Nigeria, using a simple chemotherapy regime that is suitable for these resource poor regions.
Over 500 children have been treated initially with a simple and inexpensive three-drug regimen originally developed in Africa in the early 1970s, and still widely used. Patients who achieve only partial response, or who have recurrence shortly after therapy is complete, i.e., are resistant to this regime, are given a second regimen which has proved to be effective even in patients who do not achieve remission or relapse with the first-line therapy, resulting in an approximately 38 percent complete response rate in these resistant patients and improving long-term survival.
Mother and her child with Burkitt lymphoma are at the Ocean Road Cancer Institute in Tanzania. Credit: Used with the permission of INCTR
Mother and her child with Burkitt lymphoma are at the Ocean Road Cancer Institute in Tanzania. Credit: Used with the permission of INCTR
Overall survival, in excess of 60 percent at two years and beyond, is much lower than that in Europe and the United States, for example, where much more intensive regimens can be used, but represents a marked improvement in outcome for Africa. So far, HIV-positive patients constitute only some four percent of children with Burkitt lymphoma, but their survival rate, when treated with anti-retroviral therapy in addition to the same therapy received by the HIV-negative children, is essentially identical, although numbers to date of HIV-positive patients are small.
Researchers plan to use these cancer centers as training sites to improve regional and national treatment of children with other cancers. A computerized data base, specially designed for the African setting will be used to collect and analyze data, and local health providers will learn to track, monitor, and measure outcomes of patient care (toxicity and response) so that these, and future children with cancer will receive better treatments for their disease.
The next step in the Burkitt lymphoma study will be to combine the two regimens from the beginning in high-risk patients, which is likely to result in much better survival rates.

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