Surgical resection is still recommended as the optional treatment for colorectal liver metastasis (CLM) patients. There are two main concerns for resectable colorectal liver metastasis which remain controversial: surgical time and surgical type. As for the former, synchronous resection of primary colorectal tumor and liver metastasis, with the reason of fare overall survival rate and absence of a second surgery, has gained wide population from gastrointestinal surgeons who believe it will bring benefits to CLM patients. With regard to surgical type, Open liver resection is the optimum choice for CLM patients no matter what the metastasis profile is. And for management of primary tumor, laparoscopic procedure is mature in surgical skill and has been evidenced equivalent overall survival rate compared with open resection. So, primary colorectal tumor resection could be either open or laparoscopic procedure. Therefore, the investigators team conducted the controlled trial to compare two surgical procedures in treatment of resectable colorectal liver metastasis. Patients will be randomly assigned into conventional laparotomy group for simultaneously resection of both primary colorectal tumor and liver metastasis, or laparoscopic-assisted small-incision group for resection of laparoscopic colorectal tumor combined with synchronously small-incision open resection of liver metastasis. The aim of this trial is to observing short-term operative effects after surgeries.

Nowadays, colorectal liver metastasis (CLM) is gaining wide population from multi-disciplinary doctors including gastroenterologists, oncologists, and hepatic doctors for its increasing incidence and poor prognosis. Nearly, 15%-25% of colorectal cancer patients present with simultaneous liver metastasis at the time of diagnosis and 20%-35% patients are evaluated with primary tumor and liver metastasis resectable synchronously. Although the use of chemotherapy regimen has been certified favorable outcomes, surgical resection is still recommended as the optional treatment for CLM patients. However, there are two main concerns for resectable colorectal liver metastasis which remain controversial: surgical time and surgical type. As for the former, a latest evidence shows synchronous resection of primary colorectal tumor and liver metastasis, with the reason of fare overall survival rate and absence of a second surgery. Moreover, an increasing number of surgeons favor synchronous resection from their initial experience and they believe it will bring benefits to CLM patients.

With regard to surgical type, although laparoscopic liver resection has been proven feasible, safe and efficient in management of liver metastasis, this procedure is limited in selected patients such as tumor size less than 10 centimeters or located in left liver. In addition, laparoscopic liver resection is technically difficult which is applied in most medical centers. So open liver resection may be the optimum choice for CLM patients no matter what the metastasis profile is. In the management of primary tumor, laparoscopic procedure is mature in surgical skill and has been evidenced equivalent overall survival rate compared with open resection. A research conducted by Arezzo also confirms lower 30-day morbidity of laparoscopic colorectal cancer resection. Unlike liver metastasis resection, primary colorectal tumor resection could be either open or laparoscopic procedure.

Therefore, the investigators team conducted the controlled trial to compare two surgical procedures in treatment of resectable colorectal liver metastasis. Patients will be randomly assigned into conventional laparotomy group for simultaneously resection of both primary colorectal tumor and liver metastasis, or laparoscopic-assisted small-incision group for resection of laparoscopic colorectal tumor combined with synchronously small-incision open resection of liver metastasis. The aim of this trial is to observing short-term operative effects after surgeries.

Inclusion Criteria:

1. Pathologically confirmed resectable upper rectal cancer, sigmoid cancer, and left colon cancer
2. MRI/CT confirmed resectable liver metastasis after muti-disciplinary team assessment
3. No evidence of other metastasis
4. Organs function well to tolerance simultaneous surgery, especially liver function
5. No special treatment before surgery
6. Informed consent was written

Exclusion Criteria:

1. Right colon cancer and transverse colon cancer
2. Pregnant or lactating women
3. A history of malignant tumor within 5 years
4. There was contraindication for operation
5. Discovery of metastasis in other organs in the operation
6. With mental disorder