The presence of sarcopenia before lung resection surgery might be an important factor of short-term and long-term prognosis in lung cancer patients. Through this study, investigators plan to demonstrate evidence whether sarcopenia is a useful clinical biomarker for risk stratification in elderly patients undergoing lung cancer surgery.

Sarcopenia is a syndrome characterized by a decrease in the amount and function of skeletal muscle, and is known to have a prevalence of about 6-10% in 65 years of age or older and about 20-25% in 70 years of age or older. Recently, many studies have been conducted on the clinical importance of sarcopenia, and it has been reported that sarcopenia is significantly associated with a decline in quality of life and physical activity in the elderly population, as well as harmful clinical outcomes in postoperative patients and poor long-term outcomes in various solid cancer patients. Due to the promising result of lung cancer screening trial, lung cancer has been included in national cancer screening in South Korea since last year. As a result, more people are being diagnosed with lung cancer early. Furthermore, the number of patients having surgical resection for lung cancer is steadily growing, and as life expectancy rises, even older patients are increasingly considering surgical treatment. It's critical to appropriately assess risk in older individuals before and after surgery, and sarcopenia is considered a significant fartor for major surgery. According to studies on the association between sarcopenia and the postoperative clinical outcome of lung cancer surgery, sarcopenia evaluated by computed tomography has demonstrated to be associated with a poor surgical outcome and long-term prognosis. However, according to two recognized guidelines for sarcopenia (European Working Group on Sarcopenia in Elder People, and Asian Working Group for Sarcopenia), sarcopenia is supposed to comprehensively evaluate muscle mass, muscle strength, and physical activity. Regarding muscle mass, it is recommended to measure through dual energy-ray absoptiometery or bioelectrial impedance analysis. However, so far, there are no studies that have conducted an accurate evaluation of sarcopenia in elderly lung cancer patients and analyzed the relationship between them and the clinical outcome after lung cancer surgery.

Inclusion Criteria:

• Patients planning to perform curative surgery for confirmed lung cancer and pulmonary nodules suspected for lung cancer
• Patients or legal representatives who could understand and write written consent prior to the initiation of the clinical trial and are able to comply with the requirements for the clinical trial

Exclusion Criteria:

• Patients with treatment history for lung cancer or other solid cancer within 5 years (except patients with adenocarcinoma in situ for lung cancer)
• Patients who need simultaneous surgery with lung caner surgery for other accompanying diseases
• Patients who are not eligible to participate in the study judged by the researcher

Patients above the age of 70 who are planning to undergo curative surgery for proven lung cancer or pulmonary nodules suspected for lung cancer