Treatment strategy for colorectal cancer with resectable synchronous liver metastases: Is any evidence-based strategy possible?

Fifteen percent to twenty-five percent of patients affected by colorectal cancer presents with liver metastases at diagnosis. In resectable cases, surgery is the only potentially curative treatment and achieves survival rates up to 50% at 5 years. Management is complex, as colorectal resection, liver resection, chemotherapy, and, in locally advanced mid/low rectal tumors, radiotherapy have to be integrated. Modern medical practice usually relies on evidence-based protocols. Levels of evidence for synchronous metastases are poor: published studies include few recent prospective series and several retrospective analyses collecting a limited number of patients across long periods of time. Data are difficult to be generalized and are mainly representative of single centre's experience, biased by local recruitment, indications and surgical technique. In this context, surgeons have to renounce to "evidence-based medicine" and to adopt a sort of "experience-based medicine". Anyway, some suggestions are possible. Simultaneous colorectal and liver resection can be safely performed whenever minor hepatectomies are planned, while a case-by-case evaluation is mandatory in case of more complex procedures. Neoadjuvant chemotherapy is preferentially scheduled for patients with advanced metastatic tumors to assess disease biology and to control lesions. It can be safely performed with primary tumor in situ, even planning simultaneous resection at its end. Locally advanced mid/low rectal tumor represents a further indication to neoadjuvant therapies, even if treatment's schedule is not yet standardized. In summary, several issues have to be solved, but every single HPB centre should define its proper strategy to optimize patient's selection, disease control and safety and completeness of surgery.