“…Some studies indicated the number of pulmonary metastases as a prognostic factor. 3,5,7,9,[13][14][15][16][17] Other studies reported the maximum size of lung metastasis, 5,12 disease-free interval, 10,18 prethoracotomy carcinoembryonic antigen (CEA) level, 7,16 hilar/mediastinal lymph node metastasis, 12,13 and the history of other metastatic sites 13 as significant prognostic factors. However, no definitive indications have been established at present.…”