On March 11, 2011, the Great East Japan Earthquake and subsequent giant tsunami led to catastrophic damage at the TEPCO (Tokyo Electric Power Company Holdings) Fukushima Daiichi nuclear power station. Radioactive materials spread into the Fukushima Prefecture. Although the estimated release of radioactive material was quite small, the accident caused great alarm within the population. In response, 4 months later, in July 2011, the Fukushima Health Management Survey was launched to monitor for potential radiation-induced health effects, including a large-scale thyroid surveillance program. In this issue of JAMA Otolaryngology–Head & Neck Surgery, Ohtsuru and colleagues1 provide data from the initial 2 rounds of ultrasound screening during the first 5 years after the accident, the first round between 2011 and 2013 and the second round between 2014 and 2015. Ultimately, 324 301 individuals who had been younger than 18 years at the time of the accident (the age group at higher risk of thyroid cancer after radiation exposure) were included in the analysis. During the 4 years after the accident that the screening rounds took place, 187 children and adolescents were diagnosed with thyroid cancer; the most common pathologic diagnosis was papillary thyroid cancer (98.0%).