Robotic synchronous treatment of colorectal cancer and liver metastasis: state of the art

Introduction

Colorectal cancer (CRC) remains the third cause of cancer in the United States, and liver is considered the most common site of metastasis. Surgical management of patients with primary CRC with liver metastasis is still controversial with different opinion on the subject^[1]. In patients with resectable disease, surgical resection can be considered the only potentially curative treatment even if operative sequence on the management of CRC and liver metastasis (CLM) still remain unclear^[2]. Considering that 20%-40% of all patients with CRC presents at the time of diagnosis, two main strategies are available for patients with synchronous metastasis, treating primarily the liver (liver first) or the colon (colon first). In some cases, especially in case of oligometastatic lesion of the liver, considering the spread of parenchymal sparing surgery^[3], it has been demonstrated that synchronous treatment could be considered a safe option, with acceptable morbidity and mortality^[2]. Initially, the introduction of minimally invasive surgery (MIS) has probably limited synchronous metastasis treatment due to the technical difficulties of two different kind of resection. Despite this, nowadays, various studies have demonstrated the feasibility of MIS for synchronous liver and CRC^[4]. With the introduction of robotic surgery, it represent a valid alternative lo laparoscopic surgery achieve optimal surgical and oncological outcomes. Considering robotic surgery, The well-known advantages of for laparoscopic surgery are preserved (shorter length of stay, reduced blood loss and postoperative morbidity) adding the advantages of robotic^[5-8] (magnified 3d dimensional vision, a very good access allowed for posterosuperior segment’s lesions or in contact with main liver vessels, less development of adhesions, tremor suppression, flexibility of the instruments).

The aim of this study is to present a systematic review of the literature to present the results of robotic surgery for colorectal liver metastasis in terms of short and long terms results.

Methods

The present study was designed following the PRISMA guidelines.

A systematic literature search was performed by two authors (Sammarco A, Memeo R) using PubMed, EMBASE, Scopus and Cochrane Library Central restricting to papers in English language, finding studies and articles published from 1998 to 2018, focusing the study on the synchronized treatment of the liver metastasis and the CRC. All studies including patients who underwent robotic liver resection for colorectal liver metastasis were considered as eligible for the study, especially studies who considered synchronous pure robotic resection of CLM and CRC.

The following MESH search in heading were used: “robotic”, “robot-assisted”, “minimally invasive”, “liver metastasis”, “colorectal cancer”, “stage 4”, “combined resection”, “simultaneous resection”, and “synchronous resection”.

All series containing other liver resection for different pathologies were excluded.

Results

We retrospectively reviewed collected data included OT, perioperative blood loss, disease free, overall survival. We identified 16 relevant articles, to analyse the role of the MIS in patients with colorectal liver metastases (CRLM) and previous or synchronous surgery, focusing our attention on robotic assisted surgery (RAS). Just three of this 16 concerned CRLM only.

Discussion

This systematic review confirmed the benefits of robotic approach with satisfying results, even if more extensive series and long-term results are still unclear, they are expected to be reported in the future studies.

Robotic surgery has been considered as an alternative to laparoscopic surgery to reduce the technical difficulties of laparoscopic procedure, maintaining the benefit of minimally invasive surgery. In this idea, simultaneous resection of liver and CRC could be considered a good indication for robotic surgery, due the possibility to perform both surgery in the same surgical procedure in two different surgical fields. Synchronous MIS resection has been well described in laparoscopic surgery^[12], but this strategy needs to be confirmed in robotic surgery in future, considering the increased diffusion Da Vinci robot and the progressive reduction of procedure related costs.

One of the main data available reading this review, is the pauperism of cases of synchronous resection. Only few series described resection for colorectal liver metastasis, most of them described as wedge resection. In all literature, only 8 case on 85 describe simultaneous resection, demonstrating that the synchronous approach still remains limited to few cases, despite the technical advantage of robotic surgery. As described in our paper, few synchronous procedure were performed, with two main limitations evidenced by the data, evidencing the difficulties to perform synchronous resection with major hepatectomies (only one series describe 13.5% of major resection) and to perform colorectal anastomosis, due to the higher risk of anastomotic leak in patients who underwent pedicle clamping for control of bleeding during liver resection.

In synchronous resection, usually liver resection anticipates colon resection. The management of bleeding remains a priority in this kind of resection and prolonged portal vein occlusion should be avoided in order to reduce the risk of damage the colonic anastomosis^[6,13]: the prolonged vascular clamping leads to the transient portal hypertension with edema of the intestinal mucosa, responsible of the colorectal anastomotic failure^[14], so the use of the intermittent Pringle’s maneuver has to be carefully shrewd.

Another important data evidenced by review is that despite an augmented duration of surgery due to the necessity to perform synchronous operation, operative time still remains acceptable and comparable to laparoscopic, non-impacting the length of stay.

Conversion rate still remains low, comparable to laparoscopic series^[15], confirming how the augmented dexterity probably associated to the high selection of patients guarantee a reduced rate of conversion.

Postoperative morbidity and mortality are acceptable, confirming the data reported by minimally invasive surgery. In the series of Dwyer et al.^[11], an anastomotic leakage is described, and this event strongly impact postoperative course due to the necessity of reoperation, questioning the risk of performing the colorectal anastomosis during synchronous resection.

Even if more studies are still required to define the oncologic outcome, RAS seems also expendable in a one-stage minimally invasive approach for the treatment of the simultaneous resection of primary colorectal neoplasm with synchronous liver metastases, showing advantages over conventional surgery in terms of postoperative short-term couse^[14].

Nowadays, the benefit of the robotic approach on the laparoscopic one is still a matter of debate, because of the heterogeneity of patients and the lack of long-term outcomes. This paucity of data makes difficult to draw a conclusion but, based on the few data available in this review, synchronous robotic liver and colic resection seems feasible in highly selected cases.