Table 1.

Main prognostic factors in patients with lung metastases from colorectal cancer

Prognostic factor	Overall survival		Disease-free survival
	Favorable	Negative	Favorable	Negative
Number of metastases[23,68,71,76-78,86-90]	Single	Multiple
Preoperative CEA level[61,69,86,87]	< 4-5 ng/mL	> 4-5 ng/mL
pStage of CRC[71,79,86,87]	Local disease, low Tstage, absence of nodal involvement	Advanced p and T stage, nodal Involvement
Lung metastases appearance[23,61,69-71,87,91]	Metachronous lung metastases	Bilateral lung synchronous metastasis, past history of extra thoracic metastasis	Long DFI between CRC and first detection of pulmonary metastasis	Synchronous pulmonary metastasis and CRC
Pulmonary metastasis derivation from primary site of CRC[64]	Right colon	Left colon or rectum	Not investigated	Not investigated
Lung metastasis size (cm)[61,69,78,79]	< 2 cm	> 2 cm	Not investigated	Not investigated
Mediastinal lymph node metastasis[23,69,89]	Negative	Positive	Not investigated	Not investigated
Metabolic characteristics[61,79]	Lung metastasis PET negative	Lung metastasis PET positive	Lung metastasis PET negative	Lung metastasis PET positive
Distance between lesion and resection margin (cm)[79]	> 2 cm	< 2 cm	Not investigated	Not Investigated

CRC: Colorectal cancer; CEA: Carcinoembryonic antigen; DFI: DNA fragmentation index; PET: Positron emission tomography.