Liver Metastases
Summary of Key Points
Diagnostic and Preoperative Evaluation
• Contrast-enhanced computed tomography is the most widely used imaging modality for detection of liver metastases, operative planning, and postoperative surveillance, with a sensitivity of 93% and a specificity of 100%.
• Percutaneous liver biopsy is rarely indicated.
• Underlying liver function and preoperative chemotherapy influence the minimum size of the future liver remnant after resection.
• Contraindications to resection of liver metastases have evolved such that tumor size and number are less important than obtaining an R0 resection. Resection may also be considered for patients with resectable extrahepatic metastases.
Management of Colorectal Liver Metastases
• Improvements in surgical technique and perioperative management have allowed for safer hepatic resections.
• Hepatic resection is the first-line treatment of liver metastases, with 5-year survival rates between 25% and 58%.
• Survival after resection of liver metastases is influenced by the following risk factors: node-positive primary cancer, disease-free interval, tumor number, tumor size, number of metastases, and preoperative carcinoembryonic antigen level.
• Preoperative systemic therapy, although helpful in identifying patients most likely to benefit from resection of liver metastases, is associated with hepatotoxicity and may affect postresection hepatic regeneration.
• Fluorouracil, oxaliplatin, and irinotecan-based perioperative chemotherapy regimens are most commonly used in the adjunctive treatment of liver metastases.
• In approximately 20% of patients with initially unresectable liver metastases, the metastases may become resectable after administration of neoadjuvant chemotherapy.
• Portal vein embolization and the two-staged hepatectomy are also strategies for improving the resectability of initially unresectable liver metastases.
• Unresectable liver metastases can be managed with systemic therapy and/or a variety of liver-directed techniques such as radiofrequency ablation, microwave ablation, cryotherapy, hepatic artery infusion, or yttrium-90 radioembolization.
Management of Noncolorectal Liver Metastases
• Surgical debulking of neuroendocrine liver metastases is widely accepted to improve symptoms and prolong survival but is associated with high recurrence rates.
• Noncolorectal nonneuroendocrine liver metastases are increasingly being resected, but outcomes are generally poorer than for colorectal liver metastases.
1. Regarding resection of liver metastases, which of the following statements is true?
A Nonanatomic resections have similar survival when compared with anatomic resections.
B Survival is dependent on the distance of a negative margin.
C Simultaneous colectomy and segmentectomy should not be performed.
D Intraoperative blood loss is minimized by maintenance of central venous pressure greater than 4.
2. Which of the following is a current absolute contraindication to resection of liver metastases?
3. What is the minimum future liver remnant for a patient with normal liver function who did not undergo neoadjuvant chemotherapy?
4. Which of the following statements regarding radiofrequency ablation (RFA) is true?
A RFA is more efficacious in large tumors.
B Tumor tissue is destroyed via microporation.
C RFA can only be administered percutaneously.
D Proximity to vascular structures causes nonuniformity of tissue destruction.
E Prospective randomized trials have demonstrated its superiority to other liver-directed techniques.
5. A 67-year-old woman underwent resection of a primary colon cancer with 4 of 18 positive lymph nodes. She was treated with adjuvant FOLFOX. Six months later, her postoperative computed tomography scan demonstrated three right lobe liver metastases ranging in size from 1.5 to 4 cm. Her carcinoembryonic antigen (CEA) level was 225 ng/mL. What is the next step in management?
1. Answer: A. Surgical resection of liver metastases is the only treatment modality with curative potential and long-term survival. When compared with anatomic resections, nonanatomic resections have similar positive margin rates, recurrence patterns, and overall survival and are an excellent strategy to increase the size of the future liver remnant. Simultaneous resection of a colorectal primary cancer and liver metastases has been demonstrated to be safe in patients requiring only minor liver resections (fewer than three segments). Maintenance of low intraoperative central venous pressure (less than 4) minimizes bleeding.
2. Answer: D. Untreatable extrahepatic disease is an absolute contraindication to resection of liver metastases. Patients with resectable extrahepatic disease, particularly lung metastases, may still be candidates for resection. The number, size, and location of liver metastases are no longer considered an absolute contraindication to resection. Although surgical margins greater than 1 cm are associated with improved survival when compared with subcentimeter margins, favorable outcomes can still be obtained with subcentimeter margins.
3. Answer: A. Patients with normal liver function can be left with a future liver remnant of as little as 20% if major vascular and biliary structures can be preserved.
4. Answer: D. Vascular structures serve as heat sinks leading to nonuniformity of coagulative tissue necrosis. RFA is more efficacious in small tumors. Liver tumors are destroyed by using alternating radiofrequency current, which leads to coagulative tissue necrosis. RFA can be administered percutaneously or by using laparoscopic or open surgical techniques. No prospective randomized trials have shown the superiority of RFA to other modalities; however, many retrospective studies suggest that RFA affords a survival benefit.
5. Answer: A. This patient has a clinical risk score of 4 given her node-positive primary disease, a disease-free interval of <12 months, less than one tumor, and preoperative CEA >200 ng/mL. According to Fong’s Clinical Risk Score, she has an estimated 5-year overall survival of 25%. There are no data to suggest that any therapy other than resection will have an impact on her survival.
