Categories subclassified according to the number of operations performed Category Number of operations performed General thoracic surgery 0 6 1–24 28 25–49 72 50–99 167 100–149 129 150–199 100 ≥ 200 176 Total 678 Number of operations performed Esophageal surgery 0 76 1–4 114 5–9 96 10–19 98 20–29 47 30–39 26 40–49 21 ≥ 50 45 Total 523 Incidence of hospital mortality was included in the survey to determine nationwide status, which has contributed to Japanese surgeons’ understanding of the present status of thoracic surgery in Japan, while helping to effect progress for improving operative results by enabling them to compare their work with that of others. Hospital-to-hospital transfer in the category of esophageal surgery is not considered a form of discharge; transfer to a nursing home or a rehabilitation unit is considered hospital discharge, unless the patient subsequently dies because of complications from surgery. The reason for this was that NCD information regarding esophageal surgery does not include non-surgical cases (i.e., patients with adjuvant chemotherapy or radiation only). Because of changes in data collection related to cardiovascular surgery (initially self-reported using questionnaire sheets in each participating institution up to 2014, then by downloading an automatic package from the Japanese Cardiovascular Surgery Database (JCVSD), a cardiovascular sub-section of the NCD), the response rate is not available and is, therefore, not indicated in the cardiovascular surgery category (Table 1). When compared with data for 2016 1 and 2007 2, the number of surgeries in 2017 for congenital heart disease increased by 7.1% (9368 vs. 8744) and 0.2%, respectively; procedures for valvular heart disease increased by 0.2% (23,312 vs. 23,254) and 53.2%, respectively; surgery for thoracic aortic aneurysm increased by 8.7% (20,746 vs. 19,078) and 114.6%, respectively; ischemic heart procedures decreased by 6.6% (13,898 vs. 14,874) and 23.6%, respectively.