Pulmonary metastasectomy: a common practice based on weak evidence.

The resection of secondary metastases from the lungs is a wide-spread surgical practice. Patients are referred from coloproctology teams to thoracic surgeons specifically for this surgery. What is the expected benefit? I have explored the rationale and searched the literature in order to present these patients with a well-informed opinion for their consideration. I find only weak evidence based on uncontrolled retrospective series which have been interpreted as showing a survival benefit. This has been extrapolated to policy and practice that do not stand up to scrutiny. The practice has never been subjected to randomised trial and I will argue that the present evidence is insufficient to justify the uncontrolled use of an intervention with inescapable short-term morbidity, permanent loss of function, and major cost implications. I propose ways in which the evidence may be improved, including a trial in the areas of most uncertainty.