Symptoms and Diagnosis
Patients who present with hepatic colorectal metastases are usually asymptomatic. Symptoms such as abdominal pain and weight loss are associated with advanced (high-volume) metastases and a poor prognosis.
Serum carcinoembryonic antigen (CEA) concentration is pivotal in the detection of colorectal cancer recurrence. After resection of primary colorectal cancer, an increasing CEA concentration usually indicates recurrence. (See "Guideline for Surgical Treatment of Cancer of the Colon or Rectum" at The Society for Surgery of the Alimentary Tract (SSAT) Web site.) Overall, 78% of patients with hepatic colorectal metastases have an elevated CEA concentration. Appropriate radiologic imaging is the cornerstone for evaluation of patients with suspected hepatic colorectal metastases. These examinations include a chest x-ray and helical computed tomography of the chest and abdomen. If there is doubt about the diagnosis of metastases in the liver, magnetic resonance imaging may better characterize hepatic lesions, especially if a benign condition is suspected (e.g., a hemangioma or cyst). Positron emission tomography (PET) can be used in selected patients to detect occult disease. PET is most useful in patients at high risk for recurrence after hepatic resection (for more on high-risk patients, see Expected Outcomes below).
Treatment
Although liver resection is not the primary treatment for most patients with hepatic colorectal metastases, appropriate liver resection is the standard of care for treatment of patients with isolated hepatic colorectal metastases. Possible contraindications to the resection of hepatic colorectal metastases are the presence of extrahepatic disease and the inability to achieve complete resection. Patients with lung metastasis and direct invasion of adjacent organs, such as the diaphragm, gallbladder, and colon, may be candidates for resection if resection can be complete. The preoperative evaluation should include an assessment of associated comorbid medical conditions, which may preclude safe hepatic resection.
The resection of hepatic colorectal metastases begins with laparoscopy or a laparotomy through a midline or a subcostal incision. The abdomen is examined for evidence of extrahepatic disease. An ultrasound is performed to further evaluate the hepatic metastases. Any suspicious nodule outside the liver is biopsied, and frozen sections are obtained. The goal of the operation is to eliminate all metastases with clear resection margins. In the past, hepatic colorectal metastases were not resected in patients with more than 3 lesions or with lesions within 1 cm of major vessels (vena cava or main hepatic veins). Surgeons with experience in hepatobiliary surgery should evaluate patients with multiple metastases (more than 3) or lesions close to major vessels to ascertain their candidacy for resection.
Treatment must be individualized and may require a combination of techniques. Thermal ablation techniques (cryoablation or radiofrequency ablation) have been used as an adjunct to resection or in patients who are not candidates for resection. Because ablation procedures involve relatively new techniques, the proof of efficacy is awaiting mature data. Recent data suggests that radiofrequency ablation is associated with greater persistence than originally thought.
The majority of patients experience recurrence (recur) following hepatic resection of colorectal metastases. New systemic (intravenous) chemotherapy agents (such as irinotecan or oxaliplatin combined with fluoropyrimidines) have been associated with improved survival in advanced colorectal cancer. Adjuvant systemic chemotherapy should therefore be considered after hepatic resection. Because of the lack of proven efficacy, hepatic artery infusion pump chemotherapy should only be used as part of investigational protocols. Trials including combination chemotherapy (systemic and regional) are currently under way.
Risks
The perioperative mortality rate for resection of hepatic colorectal metastases at major centers is less than 5%, with complications occurring in 30% or less of patients. In patients without significant cirrhosis, up to 80% of the liver can be resected safely because of its capacity for regeneration. However, in selected patients, there may be concerns about postoperative liver failure or complications due to the small size of the remaining liver. In such patients, other measures such as preoperative portal vein embolization to induce hypertrophy of the liver remnant or the use of systemic chemotherapy to reduce the size of the metastases may be considered.
Expected Outcomes
In the absence of treatment, the prognosis for patients with hepatic colorectal metastases is dismal, with 5-year survival rates of 3% or less. Among patients treated with complete resection of hepatic colorectal metastases, 30 to 40% will remain alive for at least 5 years. Recent studies indicate an increase in the survival rates, most likely as a result of improved imaging techniques and patient selection. Patients at high risk for recurrence after hepatic resection are those who present with multiple hepatic metastases (vs single metastases), large metastatic tumors (>5 cm), a high CEA serum concentration (>200 ng/mL), a node-positive primary colorectal cancer, or synchronous tumors (primary colorectal cancer and hepatic colorectal metastases).
Qualifications
At a minimum, surgeons who are certified or eligible for certification by the American Board of Surgery, the Royal College of Physicians and Surgeons of Canada, or their equivalent should perform operations for hepatic colorectal metastases. These surgeons have successfully completed at least 5 years of surgical training after medical school graduation and are qualified to perform operations for hepatic colorectal metastases. The level of training in advanced laparoscopic techniques necessary to conduct minimally invasive surgery of the liver is important to assess. The qualifications of a surgeon performing any operative procedure should be based on training (education), experience, and outcomes.
