Rare Tumors: Opportunities and challenges from the Children's Oncology Group perspective.

While all childhood cancers are rare, tumors that are particularly infrequent or underrepresented within pediatrics are studied under the umbrella of the Children's Oncology Group Rare Tumor committee, divided into the Retinoblastoma and Infrequent Tumor subcommittees. The Infrequent Tumor subcommittee has traditionally included an emphasis on globally rare tumors such as adrenocortical carcinoma, nasopharyngeal carcinoma, or those tumors that are rare in young children, despite being common in adolescents and young adults, such as colorectal carcinoma, thyroid carcinoma, and melanoma. Pleuropulmonary blastoma, gonadal stromal tumors, pancreatic tumors including pancreatoblastoma, gastrointestinal stromal tumor, nonmelanoma skin cancers, neuroendocrine tumors, and desmoplastic small round cell tumors, as well as other carcinomas are also included under the heading of the Children's Oncology Group Rare Tumor committee. While substantial challenges exist in rare cancers, inclusion and global collaboration remain key priorities to ensure high quality research to advance care.