Unusual Cancers of Childhood Treatment (PDQ®)–Health Professional Version

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General Information About Unusual Cancers of Childhood

Introduction

Cancer in children and adolescents is rare, although the overall incidence of childhood cancer has been slowly increasing since 1975.[1] Referral to medical centers with multidisciplinary teams of cancer specialists experienced in treating cancers that occur in childhood and adolescence should be considered for children and adolescents with cancer. This multidisciplinary team approach incorporates the skills of the primary care physician, pediatric surgeons, radiation oncologists, pediatric medical oncologists/hematologists, rehabilitation specialists, pediatric nurse specialists, social workers, and others to ensure that children receive treatment, supportive care, and rehabilitation that will achieve optimal survival and quality of life. (Refer to the PDQ Supportive and Palliative Care summaries for specific information about supportive care for children and adolescents with cancer.)

Guidelines for pediatric cancer centers and their role in the treatment of pediatric patients with cancer have been outlined by the American Academy of Pediatrics.[2] At these pediatric cancer centers, clinical trials are available for most types of cancer that occur in children and adolescents, and the opportunity to participate in these trials is offered to most patients/families. Clinical trials for children and adolescents diagnosed with cancer are generally designed to compare potentially better therapy with therapy that is currently accepted as standard. Most of the progress made in identifying curative therapy for childhood cancers has been achieved through clinical trials. Information about ongoing clinical trials is available from the NCI website.

Dramatic improvements in survival have been achieved for children and adolescents with cancer. Between 1975 and 2010, childhood cancer mortality decreased by more than 50%.[3] Childhood and adolescent cancer survivors require close monitoring because cancer therapy side effects may persist or develop months or years after treatment. (Refer to the PDQ summary on Late Effects of Treatment for Childhood Cancer for specific information about the incidence, type, and monitoring of late effects in childhood and adolescent cancer survivors.)

Childhood cancer is a rare disease with about 15,000 cases diagnosed annually in the United States in individuals younger than 20 years.[4] The U.S. Rare Diseases Act of 2002defines a rare disease as one that affects populations smaller than 200,000 persons and, by definition, all pediatric cancers are considered rare. The designation of a pediatric rare tumor is not uniform among international groups:

The Italian cooperative project on rare pediatric tumors (Tumori Rari in Eta Pediatrica [TREP]) defines a pediatric rare tumor as one with an incidence of less than two cases per 1 million population per year and is not included in other clinical trials.[5]
The Children's Oncology Group (COG) has opted to define rare pediatric cancers as those listed in the International Classification of Childhood Cancer subgroup XI, which includes thyroid cancer, melanoma and nonmelanoma skin cancers, and multiple types of carcinomas (e.g., adrenocortical carcinoma, nasopharyngeal carcinoma, and most adult-type carcinomas such as breast cancer, colorectal cancer, etc.).[6] These diagnoses account for about 4% of cancers diagnosed in children aged 0 to 14 years, compared with about 20% of cancers diagnosed in adolescents aged 15 to 19 years (refer to Figures 1 and 2).[7] Most cancers within subgroup XI are either melanomas or thyroid cancer, with the remaining subgroup XI cancer types accounting for only 1.3% of cancers in children aged 0 to 14 years and 5.3% of cancers in adolescents aged 15 to 19 years.

These rare cancers are extremely challenging to study because of the low incidence of patients with any individual diagnosis, the predominance of rare cancers in the adolescent population, and the lack of clinical trials for adolescents with rare cancers such as melanoma.

Pie chart showing age-adjusted and age-specific cancer incidence rates for patients aged 0-14 years (SEER 2009-2012). — Figure 1. Age-adjusted and age-specific (0–14 years) Surveillance, Epidemiology, and End Results cancer incidence rates from 2009 to 2012 by International Classification of Childhood Cancer group and subgroup and age at diagnosis, including myelodysplastic syndrome and group III benign brain/central nervous system tumors for all races, males, and females.

Pie chart showing age-adjusted and age-specific cancer incidence rates for patients aged 15-19 years (SEER 2009-2012). — Figure 2. Age-adjusted and age-specific (15–19 years) Surveillance, Epidemiology, and End Results cancer incidence rates from 2009 to 2012 by International Classification of Childhood Cancer group and subgroup and age at diagnosis, including myelodysplastic syndrome and group III benign brain/central nervous system tumors for all races, males, and females.

Several initiatives to study rare pediatric cancers have been developed by the COG and other international groups, such as the International Society of Paediatric Oncology (Société Internationale D'Oncologie Pédiatrique [SIOP]). The Gesellschaft für Pädiatrische Onkologie und Hämatologie (GPOH) rare tumor project was founded in Germany in 2006.[8] The Italian cooperative project on rare pediatric tumors (TREP) was launched in 2000,[5] and the Polish Pediatric Rare Tumor Study Group was launched in 2002.[9] In Europe, the rare tumor studies groups from France, Germany, Italy, Poland, and the United Kingdom have joined in the European Cooperative study Group on Pediatric Rare Tumors (EXPeRT), focusing on international collaboration and analyses of specific rare tumor entities.[10] Within the COG, efforts have concentrated on increasing accrual to the COG registry (now known as the Childhood Cancer Research Network/Project Every Child) and the rare tumor bank, developing single-arm clinical trials, and increasing cooperation with adult cooperative group trials.[11] The accomplishments and challenges of this initiative have been described in detail.[6,12]

The tumors discussed in this summary are very diverse; they are arranged in descending anatomic order, from infrequent tumors of the head and neck to rare tumors of the urogenital tract and skin. All of these cancers are rare enough that most pediatric hospitals might see less than a handful of some histologies in several years. The majority of the histologies described here occur more frequently in adults. Information about these tumors may also be found in sources relevant to adults with cancer.

References

Smith MA, Seibel NL, Altekruse SF, et al.: Outcomes for children and adolescents with cancer: challenges for the twenty-first century. J Clin Oncol 28 (15): 2625-34, 2010. [PUBMED Abstract]
Corrigan JJ, Feig SA; American Academy of Pediatrics: Guidelines for pediatric cancer centers. Pediatrics 113 (6): 1833-5, 2004. [PUBMED Abstract]
Smith MA, Altekruse SF, Adamson PC, et al.: Declining childhood and adolescent cancer mortality. Cancer 120 (16): 2497-506, 2014. [PUBMED Abstract]
Ward E, DeSantis C, Robbins A, et al.: Childhood and adolescent cancer statistics, 2014. CA Cancer J Clin 64 (2): 83-103, 2014 Mar-Apr. [PUBMED Abstract]
Ferrari A, Bisogno G, De Salvo GL, et al.: The challenge of very rare tumours in childhood: the Italian TREP project. Eur J Cancer 43 (4): 654-9, 2007. [PUBMED Abstract]
Pappo AS, Krailo M, Chen Z, et al.: Infrequent tumor initiative of the Children's Oncology Group: initial lessons learned and their impact on future plans. J Clin Oncol 28 (33): 5011-6, 2010. [PUBMED Abstract]
Howlader N, Noone AM, Krapcho M, et al., eds.: SEER Cancer Statistics Review, 1975-2012. Bethesda, Md: National Cancer Institute, 2015. Also available online. Last accessed June 29, 2016.
Brecht IB, Graf N, Schweinitz D, et al.: Networking for children and adolescents with very rare tumors: foundation of the GPOH Pediatric Rare Tumor Group. Klin Padiatr 221 (3): 181-5, 2009 May-Jun. [PUBMED Abstract]
Balcerska A, Godziński J, Bień E, et al.: [Rare tumours--are they really rare in the Polish children population?]. Przegl Lek 61 (Suppl 2): 57-61, 2004. [PUBMED Abstract]
Bisogno G, Ferrari A, Bien E, et al.: Rare cancers in children - The EXPeRT Initiative: a report from the European Cooperative Study Group on Pediatric Rare Tumors. Klin Padiatr 224 (6): 416-20, 2012. [PUBMED Abstract]
Musselman JR, Spector LG, Krailo MD, et al.: The Children's Oncology Group Childhood Cancer Research Network (CCRN): case catchment in the United States. Cancer 120 (19): 3007-15, 2014. [PUBMED Abstract]
Pappo AS, Furman WL, Schultz KA, et al.: Rare Tumors in Children: Progress Through Collaboration. J Clin Oncol 33 (27): 3047-54, 2015. [PUBMED Abstract]