Introduction

and Fabiana Gatti de Menezes²

(1)

Curitiba, Paraná, Brazil

(2)

São Paulo, São Paulo, Brazil

List of tables

Table 1.1	Drop-out rates in patients with hematological diseases among 2214 evaluable cases diagnosed with cancer in the period 1996–1999 in Central America and the Caribbean
Table 1.2	Drop-out rates in patients with solid tumors among 2214 evaluable cases diagnosed with cancer in the period 1996–1999 in Central America and the Caribbean

List of figures

Figure 1.1	Incidence in Europe (countries participating in EUROCARE-4) of common cancers diagnosed in children (0–14 years) between 1995 and 2002
Figure 1.2	Cancer cases in young Europeans (0–24 years), diagnosed in 1995–2002 in Europe (countries participating in EUROCARE-4), according to age
Figure 1.3	Estimates of childhood acute lymphoblastic leukemia (ALL) 5-year survival for children between 0 and 14 years, diagnosed in 2005–2009, in Europe
Figure 1.4	Incidence of cancer in children between 0 and 14 years old in Great Britain, diagnosed in 2006–2008
Figure 1.5	Incidence of cancer in children under 1 year of age in the United States between 2008 and 2012
Figure 1.6	Incidence of cancer in children 1–4 years of age in the United States between 2008 and 2012
Figure 1.7	Incidence of cancer in children 5–9 years of age in the United States between 2008 and 2012
Figure 1.8	Incidence of cancer in children 10–14 years of age in the United States between 2008 and 2012
Figure 1.9	Incidence of cancer in children and adolescents 15–19 years of age in the United States between 2008 and 2012
Figure 1.10	Incidence of hemato-oncological disorders for the 2214 evaluable cases diagnosed with childhood cancer in the period 1996–1999 in Central America and the Caribbean
Figure 1.11	Incidence of solid tumors for the 2214 evaluable cases diagnosed with childhood cancer in the period 1996–1999 in Central America and the Caribbean

Childhood cancers are diseases that can be considered to have high survival times and major healing potential, but despite progress in oncology, there is still a group of patients who will not be cured [12, 70, 71, 78].

Childhood cancers have many common characteristics that distinguish them from tumors in adults [35, 45, 72]. Typical tumors in children seem to arise from embryonal tissues arrested at different stages of maturation; for example: retinoblastoma, hepatoblastoma, and Wilms tumor. Many morphologic features of some childhood malignant tumors, such as clear cell sarcoma of kidney, malignant rhabdoid tumor, and melanotic neuroectodermal tumor, are not encountered in those occurring in adults. Cancer in this specific group is also typified by the frequent occurrence of undifferentiated tumors, also termed “small round cell tumours”, such as the Ewing family of tumors, Burkitt’s lymphoma, and several acute leukemia types. Childhood neoplasms are also rarely preceded by precursor lesions [72].

Although childhood cancer is rare, it is a leading cause of death in developed countries. Cancer survival in adolescents or young adults is worse than that in children who have biologically similar cancers, probably because of the intensive treatment protocols that have been developed mainly for children. Detection of childhood cancer depends on the primary health care provided, and in most developing countries, cancer is not a public health priority; priorities in these countries are usually infectious diseases. Childhood cancer incidence rates are normally higher in developed than in developing countries; in some developing countries, many children who have cancer are never diagnosed, or are diagnosed too late, or treatment is limited, and cases are often unreported. The majority of children, and approximately 80 % of children with cancer, live in developing countries. Mortality rates are lower in developed countries, despite higher incidence rates, reflecting better diagnosis and treatment [71, 72, 76].

The development of diagnostic methods such as computerized tomography, magnetic resonance imaging, and nuclear medicine scans has increased the accessibility and the precision of diagnosis; probably this explains, in part, the increase in the incidence of central nervous system (CNS) tumors observed in the United States and Europe in recent decades, and also the low incidence rates in developing countries [72].

Some pediatric malignancies are seen predominantly in pre-school children; others, such as bone tumors, non-Hodgkin lymphomas, most cases of Hodgkin disease, and different epithelial tumors, occur in older children [72].

Most cancers occurring in adults are carcinomas and are classified by the International Classification of Disease (ICD), in which groups are classified by site; in contrast, cancers in childhood are histologically very different and some types can occur in many different sites, probably the most used classification of childhood cancer is the ICCC (International Classification of Childhood Cancer) [73]. There are 11 main groups in this classification: leukemias; lymphomas and other reticuloendothelial neoplasms; brain and spinal tumors (including non-malignant tumors); sympathetic nervous system tumors; retinoblastoma; renal tumors; hepatic tumors; bone tumors; soft-tissue sarcomas; germ-cell, trophoblastic, and other gonadal neoplasms; and carcinomas and other epithelial neoplasms [70, 73].

The financial cost of cancer is substantial, and research has shown that cancer has the most devastating economic impact, of any cause of death, in the world. It is not possible to say the worldwide economic costs of cancer exactly, but some of the total costs of cancer have been estimated to be as high as US$895 billion worldwide [71].

1.1 Childhood Cancer in Europe

About 15,000 children aged between 0 and 14 years are diagnosed with cancer every year in Europe, although this age group represents only 1 % of all cancers diagnosed [76]. In Germany, for example, the total annual incidence rate for cancer in patients more than 80 years old is currently approximately 200–300 times higher than that for children under 15 years old [81].

Primary tumours of the CNS are the second most common cancer in children aged 0–14 years in Europe, comprising over 20 % of cases [95].

European populations differ considerably in cancer survival, implying inequality of access to treatment for diseases in children, which are typically highly curable [76, 77, 96].

Figure 1.1

Incidence in Europe (countries participating in EUROCARE-4) of common cancers diagnosed in children (0–14 years) between 1995 and 2002 (Source: Based on information from Gatta et al. [76])

Between the years 1995 and 2002 in Europe, 70,579 cases of cancer in children and young adults were registered; most of the cases (26.3 %) were in children between 0 and 4 years old [76].

Figure 1.2

Cancer cases in young Europeans (0–24 years), diagnosed in 1995–2002 in Europe (countries participating in EUROCARE-4), according to age (Source: Based on information from Gatta et al. [76])

Survival rates for childhood cancer vary throughout Europe, with lower 5-year survival rates observed in Eastern Europe compared with other regions. The survival rates for Northern and Central Europe are similar to those found in the United States [71, 75].

In Europe, the best 5-year survival rate for children between 0 and 14 years old diagnosed with acute lymphoblastic leukemia (ALL)—which is the most frequent hemato-oncological disease in children worldwide—in the years 2005–2009, was in Germany, with 91.8 % of these children with 5-year survival, followed by Austria, with 91.1 %. These rates have shown that the survival of children with ALL in Europe is considerably higher than that in developing countries [75].

Figure 1.3

Estimates of childhood acute lymphoblastic leukemia (ALL) 5-year survival for children between 0 and 14 years, diagnosed in 2005–2009, in Europe (Source: Based on World Health Organization information [75])

In Europe, survival at 5 years from diagnosis for children between 0 and 14 years, for all cancers combined, is generally good, with 79 % surviving in the years 2005–2007, up from the rate in 1999 to 2001 (76 %); however, no progress has been achieved in pediatric malignancies with the poorest prognosis, and childhood cancer remains a public health issue [77].

Differences in survival were observed between countries grouped by the level of socio-economic development, according to Eurocare research. There are still disparities in the survival of children and adolescents with cancer across Europe; survival in Eastern Europe is generally 10–20 % lower than in Western Europe, and these disparities become larger for pediatric cancers with poor outcomes [72, 77, 96].

Among the predominantly white populations of Western Europe, the incidence of Hodgkin lymphoma appears to be lowest in colder regions of higher latitude; Eastern Europe is a region of intermediate incidence; nodular sclerosis is relatively rare, and the increase at ages between 10 and 14 years is not as steep as in the west of Europe [73].

In Great Britain, between the years 2006 and 2008, the most common type of childhood cancer was leukemia, with 262 cases in boys and 205 cases in girls; followed by brain, other CNS, and intracranial tumors, with 219 cases in boys and 193 cases in girls. The incidence and age distribution of ALL among children of South Asian ethnic origin are very similar to those among whites, although children of South Asian ethnic origin have a much higher incidence of Hodgkin lymphoma than white children; this can be explained by a higher incidence of the mixed cellularity subtype before age 10 years. Children of West Indian descent in Great Britain have a low relative frequency of brain tumors, and the relative frequency among children of Asian descent in Great Britain is also low, as opposed to the relative frequency of cancers of the sympathetic nervous system, in which there is no sign of any variation between ethnic groups [73, 78]. Children of West Indian descent in Great Britain also have a relatively high frequency of Wilms tumor compared with that in white children, in whom it represents 5–7 % of all childhood cancers [73].

For Hodgkin lymphoma, children and siblings of patients with this disease have a significantly increased risk of developing the disease [81].

Figure 1.4

Incidence of cancer in children between 0 and 14 years old in Great Britain, diagnosed in 2006–2008 (Source: Based on information from Cancer Research UK [78])

Hepatoblastoma is one of the rarer embryonal tumors; in general, cases are diagnosed in the first few years of life. In England and Wales, one-third of these tumors are diagnosed in infancy, and 85 % before the fifth birthday, and they appear to have very little geographic variation. The incidence rate worldwide is around 1 case per million people. In contrast, hepatocellular carcinoma has much more geographic variability, and most cases occur in children 10–14 years old. In Europe this disease is rare in childhood, occurring with about half the frequency of hepatoblastoma [73].

1.2 Childhood Cancer in North America

According to data from the U.S. Cancer Statistics Working Group, for ages 0–19, the invasive cancer incidence count showed that there were 74,104 cases of childhood cancer, classified by the ICCC, between the years 2008 and 2012 in the United States; thus, the incidence rate was 976.5 (this incidence is an age-specific rate, with the number of cases or deaths in a specified age category divided by the population in the specified age category, then multiplied by 1 million). Cancers with fewer than 16 cases reported are suppressed in this data. The most common diseases were categorized as leukemias and myeloproliferative and myelodysplastic diseases, with 19,647 cases between the years 2008 and 2012, an incidence rate of 252.5 per 1 million of children. The most common cancerous diseases in children under 1 year old in the United States were neuroblastoma and other peripheral nervous cell tumors, with 1133 cases between the years 2008 and 2012, followed by leukemias and myeloproliferative and myelodysplastic diseases, with 1021 cases; the total invasive cancer incidence rates in children under 1 year old was 5254 [70].

Figure 1.5

Incidence of cancer in children under 1 year of age in the United States between 2008 and 2012 (Source: Based on information from the U.S. Cancer Statistics Working Group [70])

The incidence of invasive cancer, classified by the ICCC, for children between 1 and 4 years old in the United States, was 18,182 cases between the years 2008 and 2012, with an incidence rate of 227.1 per million. The most common diseases were leukemias and myeloproliferative and myelodysplastic diseases, with an incidence of 7426 cases, an incidence rate of 92.7 per million, followed by CNS and miscellaneous intracranial and intraspinal neoplasms, with an incidence of 3614 cases, an incidence rate of 45.1 per million [70].

Figure 1.6

Incidence of cancer in children 1–4 years of age in the United States between 2008 and 2012 (Source: Based on information from the Cancer Statistics Working Group [70]). *Cancers with fewer than 16 cases reported are suppressed in this data

The incidence of invasive cancer, classified by the ICCC, for children between 5 and 9 years old in the United States, was 12,767 cases between the years 2008 and 2012, with an incidence rate of 127.2 per million. The most common diseases were leukemias and myeloproliferative and myelodysplastic diseases, with an incidence of 4332 cases, an incidence rate of 43.2 per million, followed by CNS and miscellaneous intracranial and intraspinal neoplasms, with an incidence of 3472 cases, an incidence rate of 34.6 per million [70].

Figure 1.7

Incidence of cancer in children 5–9 years of age in the United States between 2008 and 2012 (Source: Based on information from the Cancer Statistics Working Group [70]). *Cancers with fewer than 16 cases reported are suppressed in this data

The incidence of invasive cancer, classified by the ICCC, for children between 10 and 14 years old, in the United States, was 14,060 cases between 2008 and 2012, with an incidence rate of 137.2 per million. The most common diseases were leukemias and myeloproliferative and myelodysplastic diseases, with an incidence of 3331 cases, an incidence rate of 32.5 per million, followed by CNS and miscellaneous intracranial and intraspinal neoplasms, with an incidence of 2758 cases, an incidence rate of 26.9 per million. Different from other age groups, the data for children between 10 and 14 years old with CNS and miscellaneous intracranial and intraspinal neoplasms was very similar to the data for children in this age group with lymphomas and reticuloendothelial neoplasms; this specific group had an incidence of 2646 cases, an incidence rate of 25.8 per million [70].

Figure 1.8

Incidence of cancer in children 10–14 years of age in the United States between 2008 and 2012 (Source: Based on information from the Cancer Statistics Working Group [70]) *Cancers with fewer than 16 cases reported are suppressed in this data

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