Evolution of Surgical Treatment of Colorectal Liver Metastases in the Real World: Single Center Experience in 1212 Cases

SIMPLE SUMMARY: The main purpose of this study is to evaluate the evolution of surgical treatment of CRLM within a referral center, comparing three consecutive time periods. Trends will be assessed with a specific focus on technical issues, such as the adoption of the laparoscopic approach and strategies to induce liver hypertrophy, as well as oncological issues, such as the variation in characteristics of the disease (Clinical Risk Score and extrahepatic metastases) and long term results. The secondary endpoint will be to evaluate, through uni- and multivariate analysis, the predictive factors for inclusion to a minimally invasive approach (technical issue) and the predictive factors of overall survival (oncological issue). Results demonstrated that, within the study period, the cultural background, the maturation of technical expertise and the consolidation of the multidisciplinary team have resulted in safe expansion of the possibility to offer a curative opportunity to patients, while continuously implementing into clinical practice evidence provided by the literature. ABSTRACT: Background: In recent years, the treatment of colorectal liver metastases (CRLM) has undergone significant evolution thanks to technical improvements as well as oncological advances, which have been the subject of targeted studies aimed at understanding the details of this heterogeneous disease. The purpose of this study is to put together pieces of this complex scenario by providing an overview of the evolution that has occurred in the context of a single center within a multidisciplinary management approach. Methods: Between 2005 and 2020, 1212 resections for CRLM were performed at the Hepatobiliary Surgery Division of San Raffaele Hospital, Milan. The series was divided into three historical periods, which were compared in terms of disease characteristics and short- and long-term outcomes: Period 1, 2005–2009 (293 cases); Period 2, 2010–2014 (353 cases); Period 3, 2015–2020 (566 cases). The trends for surgical technical complexity, oncological burden of the disease, use of the laparoscopic approach and use of techniques for hepatic hypertrophy were analyzed year by year. Uni- and multivariate analyses were performed to identify factors associated with inclusion to a laparoscopic approach and with long-term prognosis. Results: The number of resections performed over the years progressively increased, with an increase in the number of cases with a high Clinical Risk Score and a high profile of technical complexity. The proportion of cases performed laparoscopically increased, but less rapidly compared to other malignant tumors. The risk of postoperative morbidity and mortality was similar in the three analyzed periods. Long-term survival, stratified by Clinical Risk Score, improved in Period 3, while overall survival remained unchanged. Conclusion: The cultural background, the maturation of technical expertise and the consolidation of the multidisciplinary team have resulted in safe expansion of the possibility to offer a curative opportunity to patients, while continuously implementing into clinical practice evidence provided by the literature.