Consequences of chemotherapy on resection of colorectal liver metastases

The response rate of colorectal metastases to chemotherapy, ranging from 50 to 60%, has been shown to be a prognostic factor. Complete pathologic and radiological response rates are approximately 4 and 7%, respectively. Hepatotoxic effects of oxaliplatin and irinotecan on the non-tumoral liver parenchyma have been reported and are incriminated in vascular changes (sinusoidal obstruction syndrome [SOS]) and chemotherapy-associated steatohepatitis (CASH). Oxaliplatin-based regimens are associated with an increased risk of vascular lesions and irinotecan-based regimens are associated with increased risks of steatosis and steatohepatitis. SOS increases morbidity after major liver resection, mostly after administration of more than six cycles of neoadjuvant systemic chemotherapy. CASH increases morbidity and mortality rates after hepatectomy. Preliminary results have shown that the addition of targeted molecular therapy (bevacizumab or cetuximab) to conventional chemotherapy does not increase the postoperative morbidity or mortality rates after hepatectomy and does not create additional injury to the non-tumoral liver parenchyma. However, bevacizumab may impair regeneration of the future remnant. Chemotherapy may reduce the sensitivity of CT scan and PET scan in the detection of metastases.