The combined-modality care of the patient with colon or rectal cancer metastatic to the liver demands a team approach. It is little wonder that there is much confusion about this topic, given the number of unique treatment options that are delivered in a sequential and reiterative process. The concept of multidisciplinary approaches to complex cancer challenges has been adopted for a variety of tumor types and situations.

Questions of therapy sequencing, therapy-associated morbidity, and disease-related morbidity that limit the use of multiple interventions have necessitated an approach that is data-driven and response-modulated. For patients with colon or rectal cancer metastatic to the liver, both oncologic and functional outcomes are important. The interaction of the modalities must be considered as well as the relative benefits of any single one.

The components of the multidisciplinary team include those with expertise in:

• Diagnostic Radiology—This specialty is important for maintaining consistency during review of the initial films, recommending appropriate additional evaluative studies, and consistently reporting with standard oncologic criteria, such as Response Evaluation Criteria In Solid Tumors (RECIST),[1] on the outcome of therapy. As a subset of the diagnostic radiologist, interventional radiologists may extend the skill set into the invasive procedures.

• Medical Oncology—These team members play a key role in assessing the drug or drug combinations that will have selected tumor responses and patient toxicity. Evaluation of specific toxicities such as those involving the gastrointestinal tract, related to age or comorbidities (hypertension) and the unique interaction of the biologic agents bevacizumab (Avastin) and cetuximab (Erbitux) on wound healing and skin effects.

• Surgical Oncology—The surgical oncologist has a responsibility to assess resectability and properly weigh the surgical complications of bevacizumab associated with wound healing, which are well established. In addition, experience with cetuximab-induced rash and skin changes can be very important in planning a successful, uncomplicated operative procedure.

Surgical Strategies

The overarching question posed to the surgeon is whether all tumors can be destroyed (resected or ablated). In a simpler era, this was a question of whether the tumor could be removed with a negative margin in a single operative procedure. Today, the primary consideration for the surgeon is not so much the location or size of the tumors but rather the volume and function of the liver postoperatively. Mathematical models[2] and the use of computerized tomograms[3] have been developed to estimate the functional liver remnant after surgical resection and correlate that with outcome. Once again, multidisciplinary expertise—including reliance on the radiologist in measuring total liver volume and postoperative liver volume—is critical.

The use of ablative tools such as cryoablation , radiofrequency ablation,[4] or microwave ablation has expanded the population of patients who can be rendered metastasis-free (R0 resection) and in some cases make the need for large resections of otherwise normal tissue unnecessary. The introduction of the two-stage hepatectomy[5] to achieve R0 status is at the same time radical, innovative, and appropriate. Surgeons specially trained in liver resection and hepatobiliary surgery are now accepting the challenge of designing operations and treatment plans that provide maximum resection and extremely low morbidity. The surgical procedures are coupled with other components of care for this patient population. Selection of a surgeon and surgical team with expertise in the assessment of postoperative liver remnant, multimodality surgical techniques, and intraoperative ultrasound is required.

Surgical organizations representing the expertise of surgical oncology and hepatobiliary surgery have come together to define a series of parameters that define resectability.[6] Rather than focusing on the amount of liver removed, they have redirected the resectability analysis on the portion of the liver remaining at the end of the resection. The consensus panel recommended that there be two contiguous Couinaud’s segments with intact vascular inflow and outflow and biliary drainage. Such definitions of resectability often exceed the technical skills of the general surgeon and require specific training in surgical oncology or hepatobiliary surgery. Thus, it is important to recognize that these definitions are made with an expectation of advanced training and experience. Finally, the surgical decision of resectability must also be balanced against patient comorbidities and disease-based risk.