Introduction

Cancer in children and adolescents is rare, although the overall incidence has slowly increased since 1975.[1] Children and adolescents with cancer should be referred to medical centers that have a multidisciplinary team of cancer specialists with experience treating the cancers that occur during childhood and adolescence. This multidisciplinary team approach incorporates the skills of primary care physicians, pediatric surgeons, pathologists, pediatric radiation oncologists, pediatric medical oncologists and hematologists, rehabilitation specialists, pediatric oncology nurses, social workers, child-life professionals, psychologists, nutritionists, and others to ensure that children receive treatment, supportive care, and rehabilitation to achieve optimal survival and quality of life. For specific information about supportive care for children and adolescents with cancer, see the summaries on Supportive and Palliative Care.

The American Academy of Pediatrics has outlined guidelines for pediatric cancer centers and their role in the treatment of children and adolescents with cancer.[2] At these centers, clinical trials are available for most types of cancer that occur in children and adolescents, and the opportunity to participate is offered to most patients and their families. Clinical trials for children and adolescents diagnosed with cancer are generally designed to compare potentially better therapy with current standard therapy. Other types of clinical trials test novel therapies when there is no standard therapy for a cancer diagnosis. Most of the progress in identifying curative therapies 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 2020, childhood cancer mortality decreased by more than 50%.[3-5] Childhood and adolescent cancer survivors require close monitoring because side effects of cancer therapy may persist or develop months or years after treatment. For information about the incidence, type, and monitoring of late effects in childhood and adolescent cancer survivors, see Late Effects of Treatment for Childhood Cancer.

Childhood cancer is a rare disease, with about 15,000 cases diagnosed annually in the United States in individuals younger than 20 years.[6] The U.S. Rare Diseases Act of 2002 defines a rare disease as one that affects populations smaller than 200,000 people. Therefore, all pediatric cancers are considered rare.

The designation of a rare tumor is not uniform among pediatric and adult groups. In adults, rare cancers are defined as those with an annual incidence of fewer than six cases per 100,000 people. They account for up to 24% of all cancers diagnosed in the European Union and about 20% of all cancers diagnosed in the United States.[7,8] In children and adolescents, the designation of a rare tumor is not uniform among international groups, as follows:

These rare cancers are extremely challenging to study because of the relatively few patients with any individual diagnosis, the predominance of rare cancers in the adolescent population, and the small number of clinical trials for adolescents with rare cancers.

Some investigators have used large databases, such as the Surveillance, Epidemiology, and End Results (SEER) Program and the National Cancer Database, to gain more insight into these rare childhood cancers. However, these database studies are limited. Several initiatives to study rare pediatric cancers have been developed by the COG and other international groups, including the Société Internationale D'Oncologie Pédiatrique (SIOP). The Gesellschaft für Pädiatrische Onkologie und Hämatologie (GPOH) rare tumor project was founded in Germany in 2006.[11] The Italian Tumori Rari in Eta Pediatrica (TREP) group was launched in 2000,[12] and the Polish Pediatric Rare Tumor Study Group was launched in 2002.[13] In Europe, the rare tumor study groups from France, Germany, Italy, Poland, and the United Kingdom joined to become the EXPeRT group, focusing on international collaboration and analyses of specific rare tumor entities.[14] Within the COG, efforts have concentrated on increasing accrual to COG registries (Project Every Child) and tumor banking protocols, developing single-arm clinical trials, and increasing cooperation with adult cooperative group trials.[15] The accomplishments and challenges of this initiative have been described in detail.[10,16]

The tumors listed 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 pediatric hospitals might see less than a handful of some histologies in several years. Most of the histologies listed here occur more frequently in adults. Information about these tumors may also be found in sources relevant to adults with cancer.

The Rare Cancers of Childhood Treatment summary has been separated into individual summaries for each topic. Please use the lists below or the following link to find the individual summaries: PDQ Cancer Information Summaries: Pediatric Treatment.