One-stage versus two-stage surgery for initially unresectable colorectal cancer liver metastases: post hoc analysis of the CAIRO5 trial.

Patients with initially unresectable CRLM were included from the phase 3 CAIRO5 study. In patients in whom both one-stage and two-stage approaches were suggested by individual panel surgeons, these approaches were compared. The study population includes only patients for whom both approaches were discussed by the panel surgeons. Overall survival curves were estimated with the Kaplan-Meier method and compared with the two-sided stratified log-rank test. Other surgical and postoperative outcomes were compared using a two-sample t test and Pearson's χ2 test or Fisher's exact test, as appropriate.

One-stage surgery with/without ablation appears to be the optimal treatment approach for patients with initially unresectable CRLM for whom both one- and two-stage approaches are considered. Nonetheless, two-stage surgery remains vital for complex CRLM.

Local surgeons planned one-stage versus two-stage surgery in 53 versus 51 patients, respectively. In the one-stage versus two-stage surgery groups, the median age was 59 (interquartile range (i.q.r.) 52-69) versus 59 (i.q.r. 53-68) years, respectively, and the median number of CRLM was 9 (i.q.r. 6.5-13) versus 10 (i.q.r. 7.5-14), respectively. Median overall survival was 46.5 versus 34.0 months (HR 0.61; 95% confidence interval 0.38 to 0.99; P = 0.043) with planned one-stage versus two-stage surgery, respectively. In one-stage versus two-stage surgery, Clavien-Dindo grade ≥ 3 complications occurred in 11 versus 13 patients (P = 0.567), portal vein embolization was performed in 2 versus 41 patients (P < 0.001), and local treatment was complete (R0/R1 resection or ablation of all CRLM) in 52 versus 29 patients (P < 0.001), respectively. Major liver resection was performed in 19 versus 28 patients with complete planned one-stage versus two-stage surgery, respectively, with a corresponding 32 versus 12 patients undergoing ablation.

Considerable variability exists among liver surgeons in assessing resectability and local treatment planning of initially unresectable colorectal cancer liver-only metastases (CRLM). This study analysed short-term and survival outcomes of one-stage versus two-stage surgery for CRLM.