پیوند کبد برای متاستازهای کبدی سرطان کولورکتال غیر قابل تنظیم The New Era of Transplant Oncology: Liver Transplantation for Nonresectable Colorectal Cancer Liver Metastases

1. Background Colorectal cancer (CRC) is the third most common diagnosed cancer and the fourth cause of cancer-related mortality worldwide [1]. In 2012, there were over 1.3 million new cases diagnosed and approximately 700,000 related deaths worldwide [1]. In Canada, CRC accounts for 13% of all cancers. In 2017, CRC has a projected incidence of 80 new cases per 100.000 people and 9,400 deaths related to this cancer [2]. The CRC incidence is higher in developed countries and its rising among people younger than 55 years old [3, 4]. Approximately 15–25% of CRC patients will have distant metastases at the time of primary diagnosis, mainly to the liver [5]. Another 18%–25% patients will develop distant metastases within 5 years from the first diagnosis [6]. Over the past decade, the survival of patients with metastatic CRC has improved substantially [7]. The 2-year overall survival (OS) for stage IV CRC increased from 21% in the 1990s to 35% in the 2010s [8]. These improved outcomes are mainly a consequence of improved efficacy of systemic therapies and an increase in the number of patients undergoing surgical treatment for CRC metastasis [7, 8]. Surgical resection combined with neoadjuvant and adjuvant chemotherapy is the standard curative treatment for colorectal liver metastases (CRLM) [9, 10]. Several studies have shown 5-year OS rates of 47%–60% after hepatectomy for colorectal metastases [11–13]. However, recurrence occurs in 40%–75% of patients after liver resection [14–16]. Of these recurrences, 50% occur in the liver [15–17]. Repeated hepatectomy after hepatic recurrence has proven to be feasible and improves survival [18]. In contrast, the prognosis after recurrence of nonresectable CRC is dismal and the 5-year survival is less than 10% with palliative chemotherapy [19]. Liver resection is only feasible in 20–40% of patients with CRLM [20]. A common issue that precludes liver resection in these patients is the insufficient liver remnant volume due to large burden of metastatic disease [21]. Given that liver resection in combination with chemotherapy is the best treatment option for these patients and only a minority are eligible for this treatment, liver transplantation (LT) is an attractive option. LT would offer an R0 resection with the widest possible margin.