General Information About Childhood Extracranial Germ Cell Tumors (GCTs)
Fortunately, cancer in children and adolescents is rare, although the overall incidence of childhood cancer has been slowly increasing since 1975. 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 incorporates the skills of the primary care physician, pediatric surgical subspecialists, radiation therapists, pediatric 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. Specific information about supportive care for children and adolescents with cancer can be found in the PDQ Supportive and Palliative Care summaries.
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. At these pediatric cancer centers, clinical trials are available for most of the 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 with cancer are generally designed to compare potentially better therapy with therapy that is currently accepted as standard. The majority of the progress made in identifying curative therapies for childhood cancers has been achieved through clinical trials. Information about ongoing clinical trials is available from the NCI Web site.
Dramatic improvements in survival have been achieved for children and adolescents with cancer. Between 1975 and 2002, childhood cancer mortality decreased by more than 50%. For gonadal extracranial germ cell tumor (GCT), the 5-year survival rate has increased over the same time from 89% to 98% for children younger than 15 years and from 70% to 95% for adolescents aged 15 to 19 years. For extragonadal GCT, the 5-year survival rate from 1979 to 2002 increased from 42% to 83% for children younger than 15 years. Childhood and adolescent cancer survivors require close follow-up since 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 GCTs are rare in children younger than 15 years, accounting for approximately 3% of cancer cases in this age group.[3-5] In the fetal/neonatal age group, the majority of extracranial GCTs that occur are benign teratomas occurring at midline locations including sacrococcygeal, retroperitoneal, mediastinal, and cervical regions. Despite the small percentage of malignant teratomas that occur in this age group, perinatal tumors have a high morbidity rate due to hydrops fetalis and premature delivery.[6,7] Extracranial GCTs (particularly testicular GCTs) are much more common among adolescents aged 15 to 19 years, representing approximately 14% of cancer diagnoses in this age group. The distribution of extracranial GCTs by 5-year age group and by gender is shown in Table 1 below.Table 1. Extracranial Germ Cell Tumors by Age Group and Gendera
|0–4 years||5–9 years||10–14 years||15–19 years|
|aRates are per million children from 1986 to 1995 for the nine SEER regions plus Los Angeles.|
GCTs develop from primordial germ cells, which migrate during embryogenesis from the yolk sac through the mesentery to the gonads.[8,9] Childhood extracranial GCTs can be divided into gonadal and extragonadal types. Most childhood extragonadal GCTs arise in midline sites (i.e., sacrococcygeal, mediastinal, and retroperitoneal); the midline location may represent aberrant embryonic migration of the primordial germ cells.
The histologic and genetic properties of these tumors are heterogeneous and vary by primary tumor site and the gender and age of the patient.[10,11] Histologically identical GCTs that arise in younger children have different biological characteristics from those that arise in adolescents and young adults.References
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- Guidelines for the pediatric cancer center and role of such centers in diagnosis and treatment. American Academy of Pediatrics Section Statement Section on Hematology/Oncology. Pediatrics 99 (1): 139-41, 1997. [PUBMED Abstract]
- Miller RW, Young JL Jr, Novakovic B: Childhood cancer. Cancer 75 (1 Suppl): 395-405, 1995. [PUBMED Abstract]
- Ries LA, Smith MA, Gurney JG, et al., eds.: Cancer incidence and survival among children and adolescents: United States SEER Program 1975-1995. Bethesda, Md: National Cancer Institute, SEER Program, 1999. NIH Pub.No. 99-4649. Also available online. Last accessed October 18, 2013.
- Poynter JN, Amatruda JF, Ross JA: Trends in incidence and survival of pediatric and adolescent patients with germ cell tumors in the United States, 1975 to 2006. Cancer 116 (20): 4882-91, 2010. [PUBMED Abstract]
- Isaacs H Jr: Perinatal (fetal and neonatal) germ cell tumors. J Pediatr Surg 39 (7): 1003-13, 2004. [PUBMED Abstract]
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- McIntyre A, Gilbert D, Goddard N, et al.: Genes, chromosomes and the development of testicular germ cell tumors of adolescents and adults. Genes Chromosomes Cancer 47 (7): 547-57, 2008. [PUBMED Abstract]
- Hawkins EP: Germ cell tumors. Am J Clin Pathol 109 (4 Suppl 1): S82-8, 1998. [PUBMED Abstract]
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