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World J Clin Oncol. Oct 10, 2014; 5(4): 660-666
Published online Oct 10, 2014. doi: 10.5306/wjco.v5.i4.660
Chronic obstructive pulmonary disease as a risk factor for lung cancer
Yuichi Takiguchi, Ikuo Sekine, Shunichiro Iwasawa, Ryota Kurimoto, Koichiro Tatsumi
Yuichi Takiguchi, Ikuo Sekine, Shunichiro Iwasawa, Ryota Kurimoto, Department of Medical Oncology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
Koichiro Tatsumi, Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
Author contributions: Takiguchi Y and Tatsumi K designed the investigation; Sekine I, Iwasawa S and Kurimoto R performed the literature searches; Takiguchi Y wrote the paper; all the authors analyzed the data, read the manuscript and approved its submission to the Journal.
Supported by The Ministry of Education, Culture, Sports, Science and Technology of Japan
Correspondence to: Yuichi Takiguchi, Professor, Department of Medical Oncology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan. takiguchi@faculty.chiba-u.jp
Telephone: +81-43-2262806 Fax: +81-43-2262815
Received: December 23, 2013
Revised: January 27, 2014
Accepted: May 16, 2014
Published online: October 10, 2014
Processing time: 221 Days and 1.1 Hours
Abstract

The association between chronic obstructive pulmonary disease (COPD) and lung cancer has long been a subject of intense debate. The high prevalence of COPD in elderly smokers inevitably strengthens their coincidence. In addition to this contingent coincidence, recent studies have revealed a close association between the two diseases that is independent of the smoking history; that is, the existence of COPD is an independent risk factor for the development of lung cancer. Molecular-based evidence has been accumulating as a result of the efforts to explain the underlying mechanisms of this association. These mechanisms may include the following: the retention of airborne carcinogens followed by the activation of oncogenes and the suppression of tumor suppressor genes; the complex molecular mechanism associated with chronic inflammation in the distal airways of patients with COPD; the possible involvement of putative distal airway stem cells; and genetic factors that are common to both COPD and lung cancer. The existence of COPD in patients with lung cancer may potentially affect the process of diagnosis, surgical resection, radiotherapy, chemotherapy, and end-of-life care. The comprehensive management of COPD is extremely important for the appropriate treatment of lung cancer. Surgical resections with the aid of early interventions for COPD are often possible, even for patients with mild-to-moderate COPD. New challenges, such as lung cancer CT screening for individuals at high risk, are now in the process of being implemented. Evaluating the risk of lung cancer in patients with COPD may be warranted in community-based lung cancer screening.

Keywords: Chronic obstructive pulmonary disease; Airflow limitation; Inflammation; Lung cancer; Carcinogenesis; Cancer screening; Computed tomography screening; Early intervention

Core tip: This article reviews current perspectives on the epidemiological, clinical, and etiological problems associated with the coexistence of lung cancer and chronic obstructive pulmonary disease.