Risk stratification and goal of systemic therapy for successful surgical management of colorectal liver metastases: Oncological optimization.

For patients with stage IV colorectal cancer (CRC), curative-intent surgery has actively been performed for expecting prolonged survival outcomes. However, because the population with stage IV CRC is considerably heterogeneous, optimal selection of surgical candidate is inevitable to maximize survival outcomes. In the era of effective chemotherapy, there is an increasing need for a strategic use of chemotherapy as a part of multidisciplinary treatment to expand surgical indications and enhance the clinical outcomes. However, since the fate of each patient is difficult to predict at initial presentation, our clinical practice is rather "tailored", considering the anatomy, oncological behavior of tumor, response to chemotherapy, and patient's physical status. Given that surgery is the only treatment option for expecting cure of colorectal liver metastases (CLM), the main purpose of chemotherapy for potentially/marginally resectable disease is to clarify the likelihood of surgical benefit through testing the behavior of the tumor and to select an appropriate candidate for surgery. This process of clinical decision is actually optimization of the initial population for surgery through the optimization of treatment for each patient. In this article, theoretical bases of multidisciplinary management for CLM were revisited and the concept of "oncological optimization" underling our clinical decision was discussed.