Orange County families push for investigation into possible Ewing sarcoma cluster in Ladera Ranch
Residents of Ladera Ranch have reported six cases of the rare bone cancer Ewing sarcoma over the past decade and are urging health officials to examine potential environmental links.
Parents in the Ladera Ranch community have raised concerns after at least six cases of Ewing sarcoma were identified among children and young adults between 2013 and 2024. The cancer, which affects roughly 200 youths nationwide each year, is rare and its causes are not well understood. Dr. Janet Yoon, a pediatric hematologist-oncologist at City of Hope, said the cluster appears unusual and warrants further study, though establishing a causal relationship would be difficult.
The California Cancer Registry is reviewing local data, with results expected in the fall, to determine whether the incidence exceeds what would be expected by chance. The U.S. Centers for Disease Control and Prevention defines a cancer cluster as a higher-than-expected number of cases in a specific area, but no fixed threshold exists. Epidemiologists Logan Spector and Joseph Wiemels cautioned that apparent clusters can arise from random coincidence.
Local residents, including families who lost children to the disease, have formed the Ladera Health Watch group to collect health information, examine environmental records, and request official investigations. They are scrutinizing historic pesticide use, abandoned oil wells, and emissions from the nearby Prima Deshecha Landfill. A note in the abandonment paperwork for one well warned that construction should not proceed without further consideration, prompting calls for a re-evaluation of the well’s integrity.
While a 2023 UCLA study found an association between high county-level emissions of certain chemicals and increased Ewing sarcoma diagnoses, researchers emphasized that causality was not established. The landfill in question reports emissions of ethylbenzene and toluene that exceed the study’s high-exposure thresholds.
State agencies await the cancer registry analysis before deciding on additional actions. Meanwhile, Ladera Health Watch is collaborating with California State University, Fullerton to conduct water and soil testing, developing a low-toxicity pest-management plan, and lobbying legislators for more research funding and transparency on community cancer data.