Past

Hepatectomy for colorectal liver metastases (CRLM) has been long known to improve the prognosis of affected patients. However, the incidence of recurrence in the remnant liver or other organs remains high. Repeat hepatectomy (RH) has been considered a valuable treatment option for the early recurrence, with its usefulness reported about 1990. In the past, a decision to conduct a hepatectomy or RH for CRLM was based on certain risk score systems that considered the following prognostic factors: serosa invasion of the primary lesion, surgical margin, disease-free interval, number of tumors, the largest diameter of tumor, and value of the tumor marker.1 In addition, RH has been indicated using the same criteria as for initial hepatectomy.

Present

Treatment strategies for CRLM have changed due to the development of modern surgical techniques and chemotherapy. Consequently, a greater number of patients benefit from hepatic resection. However, the recurrence rate after initial hepatectomy remains high. Therefore, current research efforts are focusing on new prognostic factors (e.g., tumor-budding or RAS mutations). Tumor-budding is a morphologic feature at the invasive tumor edge associated with epithelial-mesenchymal transition (EMT).2 During EMT, epithelial cells lose their polarity and adhesiveness and acquire the ability to migrate and invade. As a result, cancer cells spread to other organs via the bloodstream. Moreover, EMT is associated with signaling-suppressing apoptosis and with rendering resistance to anticancer drugs and radiation. Therefore, EMT is a marker of malignancy.

Future

Tumor-budding together with other new pathologic factors will be applied in a clinical setting with molecular meaning and has potential to be of great clinical importance.3,4 Research on these factors will facilitate and advance the individualization of CRLM treatment. To date, RH remains the most effective clinical strategy for CRLM patients. New prognostic factors, however, might enable more accurate selection of patients who will benefit the most from this procedure.5