Characteristics and clinical outcomes of patients with nonsmoking small cell lung cancer in Korea

• Published in: BMC pulmonary medicine Vol. 22; no. 1; p. 200
• Main Authors: Kang, Hye Seon, Lim, Jung Uk, Yeo, Chang Dong, Park, Chan Kwon, Lee, Sang Haak, Kim, Seung Joon
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 18.05.2022; BioMed Central; BMC
• Subjects: Age; Aged; Aging; Cancer therapies; Care and treatment; Chemotherapy; Clinical outcomes; Health aspects; Hemoptysis; Humans; Korea; Lung cancer; Lung cancer, Small cell; Lung Neoplasms - diagnosis; Lung Neoplasms - epidemiology; Lung Neoplasms - therapy; Male; Medical prognosis; Metastasis; Multivariate analysis; Never-smokers; Nonsmokers; Patient outcomes; Patients; Population; Prognosis; Pulmonology; Radiation therapy; Republic of Korea - epidemiology; Retrospective Studies; Small cell lung carcinoma; Small Cell Lung Carcinoma - diagnosis; Small Cell Lung Carcinoma - epidemiology; Small Cell Lung Carcinoma - therapy; Smoking; Society; Statistics; Survival analysis; Republic of Korea; South Korea; Never-smokers; Small cell lung carcinoma; Korea
• ISSN: 1471-2466; 1471-2466
• DOI: 10.1186/s12890-022-01989-x

The aim of this study was to investigate the characteristics and clinical outcomes of patients with nonsmoking small cell lung cancer (SCLC) using a nationwide registry in Korea. The Korean Association for Lung Cancer developed a registry in cooperation with the Korean Central Cancer Registry (KCCR) and surveyed approximately 10% of recorded lung cancer cases. From 2014 to 2016, the KCCR registered 1,043 patients newly diagnosed with SCLC among a total of 8,110 lung cancer patients. In subgroup analysis, Kaplan meier survival analysis showed that the overall survival (OS) was significantly shorter in the nonsmoking subgroup than the ever-smoking subgroup of SCLC patients with extensive disease (6.99 vs. 9.68 months; P = 0.016). Among SCLC patients with limited disease, OS was also shorter in the nonsmoking subgroup, without statistical significance (19.4 vs. 23.5 months; P = 0.247). In a multivariate analysis using a Cox regression model, never smoking was not associated with shorter OS, but older age, extensive stage, poor performance status (Eastern Cooperative Oncology Group grade ≥ 2), male sex, no prophylactic cranial irradiation, and no active treatment (chemotherapy and/or radiotherapy) were associated with poor prognosis. This evaluation of an unbiased nationwide survey dataset revealed that a significant proportion of Korean SCLC patients were never-smokers. No history of smoking appeared to be a significant prognostic factor according to the univariate analysis but was confirmed to be statistically insignificant through a multivariate analysis of the total population. Reasons for a poor prognosis may include the possibility that a high rate of the elderly population is composed of nonsmokers who did not receive active treatment.