What type of registry occasionally includes patients aged 0-30 and focuses on tumors like sarcomas and leukemias?

The correct choice is the Pediatric Registry. This type of registry specifically focuses on the unique aspects of cancer in children and young adults, which typically includes individuals aged 0 to 30. The Pediatric Registry is important because cancers in this age group, such as sarcomas and leukemias, often differ biologically and in their treatment approaches when compared to cancers more commonly seen in older populations. This registry is designed not only to collect data but also to facilitate research, improve treatment protocols, and support services tailored to the needs of younger patients.

Comprehensive cancer registries gather data on all types and stages of cancer across various age groups, making them more inclusive but less specialized than pediatric registries. International registries collect and compare cancer data across different countries, which may not specifically target the pediatric population. Population-based registries monitor the incidence and outcomes of cancer in a defined population, but they typically include all age groups and may not focus specifically on the types of tumors most prevalent in younger patients. Hence, the Pediatric Registry is the most appropriate answer for the specific focus on young patients and the mentioned tumor types.