Surgery for liver-limited metastases of colorectal cancer: Considerations and advances

The challenge

Liver metastases develop in approximately 60 percent of patients with colorectal cancer at some point during the course of their disease. Left untreated, patients with metastatic liver disease have a poor prognosis.

Liver resection, paired with chemotherapy, has been shown to improve survival rates among patients with resectable colorectal liver metastasis (CLM). The five-year survival rates for patients with CLM who undergo liver resection now range from 27 to 45 percent. Current indications for resectability include:

• The ability to obtain a complete resection (macroscopic and microscopic negative margin)
• The ability to preserve two adjacent liver segments with adequate vascular inflow and outflow and biliary drainage
• The ability to preserve an adequate future liver remnant (at least 20 percent — 25 percent in a healthy liver)

Many patients with CLM are initially poor candidates for liver resection because of the distribution of tumors within the liver at presentation. Multiple advances, including new methods to improve the tumors' resectability and new surgical techniques, have increased the pool of patients eligible for surgical resection and improved patient outcomes.

New approaches to improve resectability and patient outcomes

Chemotherapy
Advances in chemotherapy to induce tumor shrinkage have increased the number of patients with tumors eligible for surgical resection. Some studies involving a combination of FOLFOX — comprising folinic acid (leucovorin), fluorouracil and oxaliplatin — and bevacizumab have shown that initially unresectable livers can become resectable in 13 percent of patients after they undergo preoperative chemotherapy.

CT scan of liver before portal vein embolization

Enlarge

CT scan of liver after portal vein embolization

Enlarge

Portal vein embolization
Patients in whom 75 percent or more of the liver needs resection may be candidates for portal vein embolization prior to resection. This procedure involves blocking blood flow to part of the liver where the tumor is located to allow more healthy liver to grow before resection.

Regeneration of the expected liver remnant increases the number of candidates for liver resection where previously their tumors were considered unresectable.

Resection of tumors outside the liver, repeat resections
Selected patients with disease outside the liver, including those with liver and lung metastases, may also be candidates for surgical resection. In a Mayo Clinic-led retrospective review of 58 patients with liver and lung metastases (57 percent with solitary lesions and 17 percent with two lesions), the five-year survival rate was 30 percent.

Data from Mayo Clinic and other centers also suggest that re-resection in selected patients with recurrent CLM offers improved survival, with approximately 40 percent five-year survival if complete resection is possible.

Surgical advances

Newer surgical instruments that coagulate tissue to reduce blood loss are helping experienced surgeons reduce the complications associated with hepatic resection.

Trocar position for laparoscopic right hepatectomy

Enlarge

Available at Mayo Clinic since 2001, laparoscopic liver resection can provide a variety of benefits, including:

• A magnified clear view of the operating field for the surgeon and shorter hospital stays
• Reduced postoperative pain
• Less incisional morbidity for patients

Laparoscopic resection also increases the ease of re-operation for repeat resections. While laparoscopic resection can provide some clear advantages for select patients, this procedure requires an experienced surgical team to ensure vascular control and complete specimen extraction.

Points to remember

• Liver resection, paired with chemotherapy, has been shown to improve survival rates among patients with resectable colorectal liver metastasis.
• Preoperative therapy, including chemotherapy and portal vein embolization to induce tumor shrinkage and increase liver remnant volume, has increased the number of patients eligible for liver resection and improved patient outcomes.
• Improved surgical instrumentation and laparoscopic resection can help experienced surgeons reduce the complications associated with liver resection.