Surgical treatment of pulmonary metastasis in colorectal cancer patients: Current practice and results

Colorectal cancer (CRC) is a frequently occurring disease, yet diagnosed at a local stage in only 40% of cases. Lung metastases (LM) appear in 5-15% of patients and, left untreated, carry a very poor prognosis. Some CRC patients may benefit from a potentially curative LM resection, but success and benefit are difficult to predict. We discuss prognostic factors of survival after lung metastasectomy in CRC patients under several scenarios (with/ without prior liver metastases; repetitive pulmonary resections). We reviewed all studies (2005-2015) about pulmonary metastases surgical management with curative intent in CRC patients, with a minimum threshold on the number of patients reported (without prior liver metastases: n ≥ 100; with prior resection of liver metastases: n ≥ 50; repetitive thoracic surgery: n ≥ 30). The picture of the prognostic factors of survival is nuanced: surgical management demonstrates clear successes and steady progress, yet there is no single success criterion; stratification of patients and selection bias impact the conclusions. Surgical management of liver and lung metastases may prolong life or cure CRC patients, provided the lesions are fully resected and patients carefully selected. Repeat lung metastasectomy is a safe approach to treat patients in selected cases. In conclusion, there is no standard for surgical management in CRC patients with pulmonary metastases. Patients with isolated unilateral lung metastasis with normal CEA level and no lymph node involvement benefit the most from surgery. Most series report good results in highly selected patients, but instances of long-term disease-free survival remain exceptional.