الفهرس 
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Abstract
Malignant liver tumors are among the most dismal of all cancers. While primary liver cancer is the sixth most common cancer worldwide, it is the third most common cause of cancer death with a mortality-to-incidence ratio exceeding 0.9(Clavien et al.;2010). Metastatic cancer is 20 times more common than primary tumors in the liver. Nearly all solid tumors can give rise to liver metastases(Doherty& Way et al.;2006).
There are a large number of treatment options for patients with malignant liver tumors. Deciding on a treatment regimen for any one patient must take into consideration the stage of malignancy, condition of the patient, condition of the liver and experience of the treating physicians(Townsend et al.;2004).
The therapies that are known to offer a high rate of complete responses and thus, a potential for cure, are surgical resection, transplantation and percutaneous ablation. Among non-curative therapies the only one that has been shown to positively impact survival is transarterial chemoembolization. Other options such as arterial embolization without chemotherapy or internal radiation do show some antitumor activity, but there is no proof of their benefit in terms of improved survival(Bruix& Sherman;2005). The poor prognosis for unresectable or metastatic liver tumors and the need to prevent progression or relapse following surgical or local therapies, remain the major drivers for developing new therapies. There is a blossom of studies testing new chemotherapeutic agents and novel molecular targeted therapies in experimental models and clinical trials(Llovet& Bruix 2008).
Preoperative evaluation of liver function using Child-Pugh scoring system, routine biochemical liver tests, many sophisticated dynamic measures of liver function as ICG, deferent imaging studies and estimation of future liver remnant with measurement of portal pressure all are central when deciding about treatment(Clavien et al.;2010).
For the vast majority of malignant hepatic tumors, complete surgical resection remains the only chance at long-term cure. The primary liver malignancies includes hepatocellular carcinoma(HCC), about 85% of primry liver tumors, cholangiocarcinoam(CCA), hepatoblastoma and other rare primaries. As a group, these tumors present major diagnostic and therapeutic challenges. Though resection can be potentially curative for these tumors, most patients with hepatobiliary cancer are discovered at a stage too advanced for complete excision(Zinner et al;2006).
Metastatic liver tumors can be classified as colorectal, neuroendocrine and non colorectal non neuroendocine (Townsend et al.;2004). In patients with colorectal liver metastases, liver resection is treatment of choice with 5-year survival after resection approaching 60%(Vauthey et al.;2005). Patients with neuroendocrine tumors often survive for many years. Multiple liver metastases are the rule with this disease, so complete resection is usually not possible. However, debulking liver resections are sometimes indicated to palliate tumor-related pain or hormonal symptoms(Doherty& Way et al.;2006). In the main, liver resection for metastatic noncolorectal, non-neuroendocrine tumors has to be considered cytoreductive and should only be used in the most favorable situation( isolated liver metastasis, long disease-free interval, long-term stability on chemotherapy). The most favorable primary sites of liver metastasis(Breast cancer, melanoma, genitourinary tumors) have the best prognosis and in well-selected patients liver resection should be considered(Townsend et al.;2004). Genrally, prognosis tends to be dismal if there is extrahepatic disease, multiple tumors, large tumors(>5cm) or a short disease-free interval(Doherty& Way et al.;2006).
Use of organ transplantation to treat malignancy is unique to the liver providing Milan criteria are established. Liver transplantation was abandoned in patients with secondary liver tumors, with exception of selective cases with neuroendocrine tumors, because results were poor(Clavien et al.;2010).
Image-guided percutaneous local ablation therapies have been playing more and more important roles. Among various local ablation therapies, radiofrequency ablation(could be considered as potentially curative) has been replacing ethanol injection as a standard therapy only after resectability has been ruled(Al Knawy et al.; 2009).
Several other treatment options as transarterial embolization, chemoembolization, radioembolization, drug-eluting beads, systemic chemotherapy and immunotherapy considered palliative and could be used as neoadjuvant or adjuvant therapy with several new agents and combinations are still under trial(Clavien et al.;2010).
Figure 5.1 Barcelona Clinic Liver Cancer staging classification and treatment. Stage0, Patients with very early hepatocellular carcinoma(HCC) are optimal candidates for resection; Stage A, patients with early HCC are candidate for radical therapies (resection, transplantation or percutaneous ablation); Stage B, patients with intermediate HCC may benefit from chemoembolization; Stage C, patients with advanced HCC may receive new agents in the setting of randomized controlled trials; Stage D, patients with end-stage disease will receive symptomatic treatment. PST(performance status test), PEI/RFA(percutaneous ethanol injection/ radiofrequency thermal ablation)(Llovet et al.;2008).
Treatment strategy for HCC varies throughout the world. Several guidelines have been proposed in the West and the East. The BCLC guideline was published in 2001, links the stage of HCC to a treatment algorithm(fig5.1)(Llovet et al.;2008). In 2005, the Liver Cancer Study Group of Japan compiled the Clinical Practice Guidelines for HCC(Makuuchi et al.;2008).
Selection of the appropriate regimen for the treatment of colorectal liver metastases will depend on the treatment strategy (fig5.2)(Clavien et al.;2010).
Figure 5.2 Treatment algorithm for patients with colorectal cancer liver metastases (CRC-LM). LM, liver metastases; PET-CT, positron emission tomography/ computed tomography. * Central structures include the inferior vena cava, bile ducts, liver veins, and liver arteries(Clavien et al.;2010).
Regarding neuroendocrine liver metastasis a protocol for treatment guidelines was published in 2006(fig5.3)(Veenendaal et al.2006).
Figure 5.3 Protocol for management of patients with neuroendocrine hepatic metastases. CT, computed tomography; MRI, magnetic resonance imaging; SRS, somatostatin receptor scintigraphy; RFA, radiofrequency ablation; LITT, laser induced thermotherapy; 131I-MIBG, Iodine-131 metaiodobenzylguanidine (Veenendaal et al.2006)