The liver is one of the most common sites of metastatic involvement for not only gastrointestinal malignancies, but also for a broad spectrum of cancers. While for gastrointestinal malignancies the pattern of blood flow via the splanchnic system seems an obvious explanation, many other malignancies (ocular melanoma and medullary thyroid carcinoma as examples) must offer other explanations likely revolving around the unique environment present with the liver. Local interventions including partial hepatectomy have been advocated for cancers whose dominant site of metastasis involves the liver, including colorectal cancer and gastrointestinal neuroendocrine cancers. Early experiences in partial hepatectomy and other local interventions for metastatic colorectal cancer defied commonly held (and largely accurate) perceptions that as a systemic matter cure would be unlikely. Although randomized trials comparing resection to observation or systemic therapy alone do not exist, large experiences have contributed to a general acceptance of the role for local hepatic treatments in metastatic colorectal cancer when confined to the liver or even in the presence of controlled, minimal volume at extrahepatic sites. This argument is supported by the positive 5-year survival rates after resection of colorectal liver metastases that is reaching 40% to 71%.1-5 Local treatments for hepatic metastases are also generally accepted in patients with gastrointestinal neuroendocrine malignancies, given the fact that hepatic dominant pattern is present in many patients and that uncontrolled hepatic tumor burdens are often the cause of ultimate demise in these otherwise “indolent” or slowly progressing malignancies.
Historically, hepatectomy in patients with noncolorectal nonneuroendocrine liver metastases (NCNNLMs) was considered to be less beneficial compared to patients with liver metastases originating from colorectal cancer or neuroendocrine tumors. Early experiences in hepatic resection for liver metastases arising from pancreas (adenocarcinoma), breast, lung, stomach, kidney, reproductive organs, and cutaneous sites led many authors to suggest a limited role, if any for this modality.6 However, this notion has been increasingly challenged during the last two to three decades. A number of factors have contributed to this reconsideration, including improvements in imaging, surgical techniques, adjuvant systemic treatments, and the overall morbidity profile of hepatic surgery. There was a threefold increase in partial liver resections for NCNNLMs in four major hepatobiliary centers in the United States comparing years 1990–1999 to 2000–2009 (Fig. 131-1) and even a fourfold increase from 1983 to 1993 compared to 1994 to 2004 in France.7,8 Notwithstanding, there are no guidelines or specific criteria as to which patients with NCNNLMs should undergo partial liver resection.
Number of partial liver resections per year for noncolorectal nonneuroendocrine liver metastases at four specialized hepatobiliary centers in the United States. (Reproduced with permission from Groeschl RT, Nachmany I, Steel JL, et al. Hepatectomy for noncolorectal non-neuroendocrine metastatic cancer: a multi-institutional analysis. J Am Coll Surg. May 2012;214(5):769–777.)