Pulmonary Metastasectomy in Colorectal Cancer (PulMiCC): Updated analysis of 93 randomised patients ‐ control survival is much better than previously assumed

AIMS: Lung metastases from colorectal cancer are resected in selected patients in the belief that this confers a significant survival advantage. It is generally assumed that the five-year survival of these patients would be near zero without metastasectomy. We have tested the clinical effectiveness of this practice in PulMiCC, a randomised controlled non-inferiority trial. METHODS: Multidisciplinary teams in 14 hospitals recruited patients with resectable lung metastases into a two-arm trial. Randomisation was remote and stratified by site with minimisation for age, sex, primary cancer stage, interval since primary resection, prior liver involvement, number of metastases, and carcinoembryonic antigen. The trial management group were blind to patient allocation until after intention to treat analysis. RESULTS: From 2010 to 2016, 93 participants were randomised, aged 35 to 86 years, with 1-6 lung metastases at a median of 2.7 years after colorectal cancer resection. 29% had prior liver metastasectomy. Characteristics were well-matched and similar to observational studies. The median survival after metastasectomy was 3.5 years (95%CI:3.1,6.6) compared with 3.8 years (95%CI:3.1,4.6) for controls. The estimated unadjusted hazard ratio for death within five years, comparing metastasectomy to control, was 0.93 (95%CI:0.56,1.56). Use of chemotherapy or local ablation was infrequent and similar in each group. CONCLUSIONS: The control group patients who do not have lung metastasectomy have better survival than is assumed. Survival in the metastasectomy group are comparable with the many single arm follow-up studies. The groups were well matched with features similar to reported case series.