Published online Oct 28, 2014. doi: 10.3748/wjg.v20.i40.14517
Revised: July 22, 2014
Accepted: September 12, 2014
Published online: October 28, 2014
Clinical practice with respect to metastatic colorectal cancer differs from the other two most common cancers, breast and lung, in that routine surveillance is recommended with the specific intent of detecting liver and lung metastases and undertaking liver and lung resections for their removal. We trace the history of this approach to colorectal cancer by reviewing evidence for effectiveness from the 1950s to the present day. Our sources included published citation network analyses, the documented proposal for randomised trials, large systematic reviews, and meta-analysis of observational studies. The present consensus position has been adopted on the basis of a large number of observational studies but the randomised trials proposed in the 1980s and 1990s were either not done, or having been done, were not reported. Clinical opinion is the mainstay of current practice but in the absence of randomised trials there remains a possibility of selection bias. Randomised controlled trials (RCTs) are now routine before adoption of a new practice but RCTs are harder to run in evaluation of already established practice. One such trial is recruiting and shows that controlled trial are possible.
Core tip: In this review we examine the present position with respect to liver and lung metastasectomy for colorectal cancer and explore the history of how these clinical practices were adopted. We find that these practices are based on observational and largely retrospective data. The mechanistic rationale and the basic science are insufficient for proof of effectiveness. Although randomised studies have been proposed none have been completed so current practice does not reach the standards required for acceptance of other therapies. We provide an update of the present position and propose a way ahead.