Is survival really better after repeated lung metastasectomy?

Abstract

Several groups have observed that average survival time after a second lung metastasectomy is longer than after a first metastasectomy. The randomised controlled trial Pulmonary Metastasectomy in Colorectal Cancer (PulMiCC) found no survival benefit from lung metastasectomy. In fact, median survival was longer, and four-year overall survival was higher, in the control group than in those randomly assigned to metastasectomy, although not significantly so. The illusion of benefit is because survival without metastasectomy has been assumed to be near zero, as stated in Society of Thoracic Surgeons' Expert Consensus Document on Pulmonary Metastasectomy 2019. It has been repeatedly found that survival is influenced by the selection of patients who have characteristics associated with better prognosis. The passage of time while monitoring and assessing patients, and observing their rate of progression, provides for immortal time bias. Reselection of the most favourable patients for repeated metastasectomy is the likely reason for any differences in survival between first and repeated metastasectomy operations.

Outcomes and prognostic factors of repeat pulmonary metastasectomy

“…There is no firm evidence of the effectiveness of repeat PM, other than observational studies. Fiorentino and Treasure [ 23 ] argued on this issue, maintaining that reselection of the most favourable patients for repeat PM is the likely reason for any differences in survival between the initial and subsequent PM procedures. In addition to PM, stereotactic body radiation therapy and radiofrequency ablation are currently available local treatment options for pulmonary metastasis.…”

The Pulmonary Metastasectomy in Colorectal Cancer study calls for reconsideration of the clinical effectiveness of this widespread practice

“…Yildiz et al draw the following conclusion from their experience: "Therefore, we have to make a vigilant follow-up for the second lung relapse to seize an opportunity for the second metastasectomy 1 ." The PulMiCC analysis of additional treatments cannot refute the belief that there is benefit from repeat metastasectomy because there was no controlled comparison, but on statistical review of the claims, it seems unlikely 12,13 . Also reported from PulMiCC are the quality of life, health utility, and the burden of additional treatments 3,11,14 .…”