In Japan, a lung cancer screening program using high-resolution CT (HRCT) has been employed for approximately 10 years. In the past decade, the detection of peripheral tumors < 2 cm in size has increased significantly because of CT examinations. In order to clarify the efficacy of the surgical intervention for screening-detected lung cancer, the surgical experiences in Tokyo Medical University were retrospectively analyzed.
Seven hundred eighty-three patients with lung cancer were treated surgically in our hospital during the past 5 years. Among them were 150 patients with peripheral nodules < 2 cm in diameter; of these 150 patients, 135 nodules were adenocarcinoma. Lobectomies were performed in 93 patients, and limited resections including video-assisted thoracoscopic surgery were performed in 42 patients; 2.5% of the patients with tumors < 1 cm in diameter had already showed N2 disease. In the patients with nodules between 1 cm and 1.5 cm and between 1.5 cm and 2 cm, lymph node involvement was recognized in 8.1% and 12%, respectively. In 16 patients who showed 100% ground-glass attenuation (GGA) and 21 patients who had between 50% and 100% GGA, there was no lymph node metastasis. In the patients with no GGA findings, the presence of lymph node metastases was not related to the size of the tumor. Five-year survival rate in the tumors < 1 cm, between 1 cm and 1.5 cm, and between 1.5 cm and 2 cm were 100%, 86.5%, and 92.4%, respectively. In the patients expressing > 50% GGA, a 100% 5-year survival rate was obtained; the patients showing < 50% GGA had 91.1% 5-year survival rate. In terms of surgical procedures, the 5-year survival rate was 100% in limited operation and 91.5% in lobectomy.