Table 1.

Summarized highlights of controversies surrounding the management of colorectal cancer liver metastases

Treatment strategy	Arguments in support of	Arguments against
The simultaneous approach	No increase of morbidity and/or mortality in carefully selected patients	Considerable increase of morbidity and/or mortality
	Removal of all cancer in a single procedure; thereby lowering the risk of disease dissemination	No time-test approach to evaluate the biological behavior of metastasis and this may result in unnecessary liver resection in rapidly progressing disease
	Similar PFS and OS compared to those with staged resection	Higher recurrence rate and a negative impact on long-term outcome
Pre-HR chemotherapy	Decreases the magnitude of resection	Delays liver resection and may result in a unresectable state in nonresponders
	Eradicates micrometastases	May lead to liver parenchyma damage and increased postoperative morbidity
	Increases R0 resection rates	No impact on PFS and OS
	Assesses responsiveness to specific chemotherapy, thus, identifying and selecting patients with favorable tumor biology. It improves PFS
Extensive resection for DLM	Response on imaging does not necessarily signify clinical or pathological response ( in up to 83% evidence of residual disease); so resect all initial sites if possible, despite disappearance on imaging	Hence, durable clinical response is as high as 62%, resect only residual macroscopic disease leaving the disappeared lesions in situ or alternatively, continue systemic chemotherapy alone
The liver-first approach	It is the liver metastasis, rather than the primary tumor, that gives rise to systematic metastatic disease, so it should be addressed first	No, it is the primary tumor that produces systemic effects promoting angiogenesis in the liver, thus favoring the spread of metastatic disease
	It avoids the risk for progression of CRLM while the patient is treated for the primary tumor, especially if complications are encountered; thereby improving median survival and 3-year survival rates	Despite apparently similar treatment protocols in those few studies, the variations in survival rates of the liver-first approach are wide; so its comparison with the bowel-first approach or the combined strategy is problematic
	Option to give systemic chemotherapy as a first step early in the treatment course that may lead to an effective response in the primary tumor and avoids resection

CRLM, colorectal liver metastasis; DLM, disappearing (no longer visible on imaging) liver metastases; HR, hepatic resection; PFS, progression free survival; OS, overall survival; Pre-HR chemotherapy, neoadjuvant chemotherapy for resectable CRLM.