Introduction: The International Registry of Lung Metastases defined a new staging system based on identified prognostic factors for long-term survival after metastasectomy. The aim of our study was to confirm the validity of the International Registry of Lung Metastases classification system in patients who underwent curative lung metastasectomy in a single center.
Methods: We retrospectively reviewed 575 patients who underwent 708 lung metastasectomies from January 1998 to October 2008. Complete curative pulmonary resections were performed in 490 cases (85%). Three hundred seventy-two patients developed lung metastases from epithelial tumors, 80 from sarcomas, 27 from melanomas, and 11 from germ cell tumors. The mean disease-free interval (DFI) was 46.6 months. Open surgical resection was performed in 479 patients. One hundred eighty-five patients had a single-lung metastasis. Lymph node dissection was performed in 353 cases.
Results: After a mean follow-up of 34 months, 247 patients (43%) had died. Multivariate analysis disclosed that completeness of resection (p < 0.0001), patients with germ cell tumors (p = 0.04), and DFI ≥36 months (p = 0.01) were also associated with a better prognosis. The actuarial survival after complete metastasectomy was 74% at 2 years and 46% at 5 years.
Conclusions: We confirmed completeness of surgery, histology, and DFI ≥36 months as independent prognostic factors. Number of metastases, presence of lymph node metastases, surgical approach, and number of metastasectomies did not statistically influence long-term survival.