Although well-established in clinical practice there have been no previous randomised controlled trials of the effect of lung metastasectomy on survival and there is doubt as to its clinical effectiveness. The most recent systematic review and meta-analysis concludes that pulmonary metastasectomy is associated with a high likelihood of recurrence, with doubling of the recurrence rate with each of three adverse prognostic factors: (i) more than one metastasis, (ii) an interoperative interval (primary resection to lung metastasectomy) less than three years, (iii) elevated CEA.