Objective: A systematic review of the literature was undertaken to estimate the differences in length of hospital stay, morbidity, mortality and long-term survival between staged and simultaneous resection of synchronous liver metastases from colorectal cancer to determine the level of evidence for recommendations of a treatment strategy.
Method: A Pub-med search was undertaken for studies comparing patients with synchronous liver metastases, who either had a combined or staged resection of metastases. Twenty-six were considered and 16 were included based on Newcastle Ottawa Quality Assessment Scale. All studies were retrospective and had a general bias, because the staged procedure was significantly more often undertaken in patients with left-sided primary tumours and larger, more numerous and bi-lobar metastases. Analyses of primary outcomes were performed using the random effects model.
Results: For the reason of the heterogeneity of the observational studies, no odds ratios were calculated. In 11 studies, there was a tendency towards a shorter hospital stay in the synchronous resection group. Fourteen studies compared total perioperative morbidity and lower morbidity was observed in favour of a combined resection. Fifteen studies compared perioperative mortality, which seemed to be lower with the staged approach. Eleven studies compared 5-year survival, which seemed to be similar in the two groups.
Conclusion: No randomized controlled trials were identified, and hence a meta-analysis was not performed. The evidence level is II to III with grade C recommendations. Synchronous resections can be undertaken in selected patients, provided that surgeons specialized in colorectal and hepatobiliary surgery are available.