This study provided the benchmark statistics on medically treated patients with non-small cell (NSCLC) and small cell (SCLC) lung cancer in Japan. Demographic background, treatment, and prognosis were obtained from patients with lung cancer pathologically diagnosed in 2012, who received non-surgical treatment. Descriptive statistics and their associations with survival were analyzed. A total of 12320 patients were registered from 314 institutions in Japan. The median age was 70 years, and 73%

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... the patients were male. The number (%) of stage I, II, III, IV diseases were 468 (3.8%), 421 (3.4%), 3260 (26.5%), and 8171 (66.3%), respectively. NSCLC and SCLC accounted for 9872 (80.1%) and 2353 (19.1%) patients, respectively. Thoracic radiotherapy-based therapy, chemotherapy, and palliative care alone were administered to 2572 (20.9%), 7790 (63.2%), and 1952 (15.8%) patients, respectively. Clinical TNM stage was one of the strongest prognostic factors with the 3-year survival rates of 62.9%, 47.3%, 40.0%, 27.8%, 37.5%, 26.5%, and 18.2% for stage IA, IB, IIA, IIB, IIIA, IIIB, and IV, respectively. Among 6158 NSCLC patients treated with chemotherapy, the 3-year survival rate was 33.4% in patients receiving epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) at some point in their clinical course, whereas it was 17.4% in patients who did not. The 3-year survival rate of SCLC was only 15.9%. In conclusion, approximately two-thirds of the patients were diagnosed as stage IV at the initial diagnosis. Use of EGFR-TKIs significantly improved the survival of patients with NSCLC.