Importance of the control of lung recurrence soon after surgery of pulmonary metastases

Purpose: In this study, we investigated factors that determined prognosis in patients who underwent surgery for metastatic lung tumors, focusing on early relapse of metastatic lung lesions after surgery, and considered countermeasures for improving long-term results based on this study. Patients: This study was performed in patients with metastatic lung tumors who underwent surgery during the 22 years after November 1975 in this department. Results: The 1-year, 3-year, and 5-year survival rates in all patients were 70%, 42%, and 37%, respectively. On comparison among the groups, there were no significant differences by gender, age, organ with the primary lesion, disease-free interval, number of metastases, or surgical procedure. However, prognosis was significantly poorer in patients with recurrent metastatic lung lesions. Prognosis was especially poor in patients with recurrence within 6 months after pneumonectomy, and this was an important factor that worsened the surgical results. Conclusions: As the mechanism of early recurrence of lung metastasis after surgery for metastatic lung tumor, multiple micrometastases (dormancy) that cannot be detected during surgery for metastatic lung tumor may be present in the lung. Establishment of a method of controlling an increase in dormant metastasis may lead to improvement of surgical results of metastatic lung tumors