Current status of molecularly targeted therapy for hepatocellular carcinoma: basic science

Conventional systemic chemotherapy has been developed with so-called anti-cancer agents, essentially screened for cytotoxicity to cultured cancer cells. However, in patients with hepatocellular carcinoma (HCC), the role of chemotherapy is quite limited because most anti-cancer agents are ineffective and relatively toxic to HCC patients with chronic liver diseases. On the other hand, accumulated understanding of the molecular mechanisms regulating cancer progression has led to novel development of molecularly targeted therapies with cytostatic agents. Recently, a phase III clinical trial revealed a multi-kinase inhibitor, Sorafenib, as the first agent leading to improved overall survival of patients with advanced HCC. A new era of HCC treatment has arrived, based on identification of deranged signaling pathways of cancer cells or their microenvironment. This review summarizes the molecular hallmarks of HCC with a focus on angiogenesis, growth signals, and mitotic stress, and a novel concept “synthetic lethality” for the targeted therapy strategy.     

Novel systemic therapy options for hepatocellular carcinoma

Hepatocellular carcinoma, a common malignancy globally, has been increasing in incidence in the United States, mostly due to the rising incidence of Hepatitis C viral (HCV) infection. The prognosis of patients with this cancer has been poor and even tumor resection has rarely been curative. However, orthotopic liver transplantation (OLT) has been associated with long-term survival benefit and cures, provided rigorous patient-selection criteria were adhered to. Liver cirrhosis is the most common precursor for HCC, and attempts have been made to prevent the progression from liver cirrhosis to HCC. Post resection adjuvant therapies have included interferon, polyprenoic acid, and adoptive immunotherapy. Finding effective systemic treatments for non-resectable HCC has been challenging and quite frustrating. The presence of liver cirrhosis and the associated volume expansion, electrolyte imbalances, decreased liver synthetic and metabolic reserve, and portal hypertension has made the design of systemic therapy for HCC a major challenge. Additionally staging of HCC using the Tumor Node Metastases (TNM) system, but ignoring the underlying liver disease made it extremely difficult to compare results of different trials. However by and large it would seem, that the more aggressive chemotherapy agents and combinations were associated with median survival times of 3-5 months. Considering the vascular nature of HCC it may be reasonable to combine tolerable chemotherapy with newly released agents with angiogenesis inhibiting properties. Thus, systemic therapy of HCC is a work in progress that calls for additional trials of tolerable newer agents and combinations.     

Hepatocellular carcinoma: are we making progress?

Hepatocellular carcinoma is a very prevalent malignancy worldwide, with increasing incidence in the United States. Despite many available treatment options, the prognosis remains poor. Surgical resection or liver transplantation still represents the only potentially curative treatments for HCC. Until more effective systemic therapies are available, different localized treatment approaches will continue to be applied in the management of this disease. Although systemic chemotherapy has been disappointing, increased understanding of the tumor biology in HCC coupled with new drug development may lead to newer agents with novel mechanisms of action that are more efficacious. The poor treatment outcome and dismal prognosis make prevention of HCC an important strategy in controlling this aggressive type of malignancy. Vaccine programs for HBV are ongoing. Efforts are underway to develop a vaccine for HCV. Interferon therapy appears to decrease the risk of developing HCC in patients with hepatitis, especially those with HCV. A number of other approaches for decreasing risk in these patients as well as in those with alcoholic-related cirrhosis are currently being evaluated.     

A narrative review of systemic treatment options for hepatocellular carcinoma: state of the art review

Hepatocellular carcinoma (HCC) is an aggressive cancer that typically develops in the setting of underlying cirrhosis of the liver. HCC commonly presents in advanced stages and if eligible orthotopic liver transplantation (OLT) and surgical resection/ablation remain as the only curative options. Prior to 2007, no systemic therapy was available that demonstrated an improvement in survival. Underlying cirrhosis and poor synthetic hepatic function provides a major challenge into effective systemic options contributing to the poor success of cytotoxic chemotherapy in HCC. The first drug to achieve clinical success was sorafenib despite the underwhelming overall survival of 3 months. Since then, other targeted therapies have shown modest benefit as well. Most recently, immunotherapy advances have come to the forefront in the management of HCC and combination therapy with immunotherapy and monoclonal antibodies have now surpassed sorafenib as first line treatment. This article will review the various approved and emerging therapies that have had a significant clinical impact and highlight the future directions and ongoing research that will hopefully translate into better outcomes in the treatment approach of advanced HCC.     

Advances in postoperative adjuvant therapy for primary liver cancer

Hepatocellular carcinoma (HCC) is a highly heterogeneous, invasive, and conventional chemotherapy-insensitive tumor with unique biological characteristics. The main methods for the radical treatment of HCC are surgical resection or liver transplantation. However, recurrence rates are as high as 50% and 70% at 3 and 5 years after liver resection, respectively, and even in Milan-eligible recipients, the recurrence rate is approximately 20% at 5 years after liver transplantation. Therefore, reducing the postoperative recurrence rate is key to improving the overall outcome of liver cancer. This review discusses the risk factors for recurrence in patients with HCC radical surgical resection and adjuvant treatment options that may reduce the risk of recurrence and improve overall survival, including local adjuvant therapy (e.g., transcatheter arterial chemoembolization), adjuvant systemic therapy (e.g., molecular targeted agents and immunotherapy), and other adjuvant therapies (e.g., antiviral and herbal therapy). Finally, potential research directions that may change the paradigm of adjuvant therapy for HCC are analyzed.     

From molecular biology to targeted therapies for hepatocellular carcinoma: the future is now

Hepatocellular carcinoma (HCC) is characterized as a highly chemoresistant cancer with no effective systemic therapy. Despite surgical or locoregional therapies, prognosis remains poor because of high tumor recurrence or tumor progression, and currently there are no well-established effective adjuvant therapies. The molecular biology of carcinogenesis and tumor progression of HCC has been increasingly understood with intense research in recent years. Several important intracellular signaling pathways such as the Ras/Raf/Mek/Erk pathway and PI3k/Akt/mTOR pathway have been recognized, and the role of several growth factors and angiogenic factors such as EGF and VEGF has been confirmed. Effective agents targeting these molecular abnormalities have been developed and widely tested in preclinical studies of HCC cell lines or xenograft models. Several agents have entered clinical trials in HCC patients, and recent data indicated that a multikinase inhibitor targeting Ras kinase and VEGFR-2, sorafenib, is effective in prolonging survival of patients with advanced HCC. The management of advanced HCC is entering the era of molecular targeting therapy, which is of particular significance for HCC in view of the lack of existing effective systemic therapy for this cancer.     

Combining local regional therapy and systemic therapy: Expected changes in the treatment landscape of recurrent hepatocellular carcinoma

Improvements in early screening, new diagnostic techniques, and surgical treatment have led to continuous downward trends in hepatocellular carcinoma (HCC) morbidity and mortality rates. However, high recurrence and refractory cancer after hepatectomy remain important factors affecting the long-term prognosis of HCC. The clinical characteristics and prognosis of recurrent HCC are heterogeneous, and guidelines on treatment strategies for recurrent HCC are lacking. Therapies such as surgical resection, radiofrequency ablation, and transhepatic arterial chemoembolization are effective for tumors confined to the liver, and targeted therapy is a very important treatment for unresectable recurrent HCC with systemic metastasis. With the deepening of the understanding of the immune microenvironment of HCC, blocking immune checkpoints to enhance the antitumor immune response has become a new direction for the treatment of HCC. In addition, improvements in the tumor immune microenvironment caused by local treatment may provide an opportunity to improve the therapeutic effect of HCC treatment. Ongoing and future clinical trial data of combined therapy may develop the new treatment scheme for recurrent HCC. This paper reviews the pattern of recurrent HCC and the characteristics of the immune microenvironment, demonstrates the basis for combining local treatment and systemic treatment, and reports current evidence to better understand current progress and future approaches in the treatment of recurrent HCC.     

肝癌化疗中药物分子瘤内分布的机制与干预策略

肝癌化疗研究主要集中在化疗药物耐药性的分子及基因机制,而忽略了抗癌药物瘤内分布不足的作用,这一机制在临床肿瘤治疗中有着相当甚至更大的影响.药物的瘤内分布取决于药物本身的性质和肿瘤微环境的影响,而通过药物结构的改进和新生血管干预对微环境的改善能更好地提高肝癌化疗的疗效.     

Radiotherapy in combination with vascular-targeted therapies

BACKGROUND: Given the critical role of tumor vasculature in tumor development, considerable efforts have been spent on developing therapeutic strategies targeting the tumor vascular network. A variety of agents have been developed, with two general approaches being pursued. Antiangiogenic agents (AAs) aim to interfere with the process of angiogenesis, preventing new tumor blood vessel formation. Vascular-disrupting agents (VDAs) target existing tumor vessels causing tumor ischemia and necrosis. Despite their great therapeutic potential, it has become clear that their greatest clinical utility may lie in combination with conventional anticancer therapies. Radiotherapy is a widely used treatment modality for cancer with its distinct therapeutic challenges. Thus, combining the two approaches seems reasonable. CONCLUSIONS: Strong biological rationale exist for combining vascular-targeted therapies with radiation. AAs and VDAs were shown to alter the tumor microenvironment in such a way as to enhance responses to radiation. The results of preclinical and early clinical studies have confirmed the therapeutic potential of this new treatment strategy in the clinical setting. However, concerns about increased normal tissue toxicity, have been raised.     

Role of the microenvironment in hepatocellular carcinoma development and progression

Hepatocellular carcinoma (HCC) is the most common form of liver cancer throughout the world. The microenvironment of the HCC is composed of non-tumor cells and their stroma, with the stroma having been implicated in the regulation of tumor growth, metastatic potential and outcome following therapy. Thus, the tumor microenvironment has become an important target for HCC treatment. In this review article, we will discuss the cellular and molecular components of the hepatoma microenvironment, effects on tumor development and progression, the relationship to prognosis, and the implications for targeting of this microenvironment in the control of HCC.     

Neoadjuvant therapy for hepatocellular carcinoma: is there an optimal approach?

Hepatocellular carcinoma (HCC) is an aggressive tumor that often occurs in the setting of chronic liver disease and cirrhosis. The incidence of hepatocellular carcinoma is increasing in the United States and worldwide. Orthotopic liver transplantation (OLT) is a viable and potentially curative option for selected patients with HCC. Locoregional therapy has been used to control HCC before transplantation because of the limited number of donor organs, to prevent tumor progression, and to decrease the incidence of dropouts from the transplant waiting list. Traditionally, multiple investigational locoregional modalities such as tumor resection, radiofrequency ablation, transarterial chemoembolization, and systemic chemotherapy have been used as "bridging" therapies. While the investigation of novel neoadjuvant treatments is justified in an effort to prevent tumor progression, the absence of randomized controlled trials leaves uncertainty about the utility of these maneuvers in improving outcome. This review summarizes the current data on the different modalities used worldwide in the neoadjuvant treatment of hepatocellular carcinoma, the rationale for these approaches, efficacy, potential complications, and future prospects.     

Nonsurgical treatment of hepatocellular carcinoma.

While surgical resection and tumor ablation are the preferred therapies for hepatocellular carcinoma (HCC), these are available or appropriate in only a minority of patients. This reflects the usual comorbidity of severe underlying liver disease that either precludes surgery or makes the surgical approach extremely dangerous. Nonetheless, regional control of HCC is highly relevant and many regional strategies have been explored, including hepatic intra-arterial chemotherapy transarterial chemoembolization, lipiodol chemoembolization, radiation therapy, cryosurgery, percutaneous ethanol injection, and radiofrequency ablation. In addition, a variety of systemic chemotherapeutic agents have been tested in HCC, including various combinations of 5-fluorouracil, doxorubicin, epirubicin, etoposide, cisplatin, and mitoxantrone, as well as interferon, tamoxifen, capecitabine, thalidomide, and octreotide. Published data regarding these regional and systemic therapies will be discussed in this review.     

Brain metastases in breast cancer

Despite therapeutic advances, the development of breast cancer brain metastases (BCBM) is still the harbinger of a dismal prognosis. Patient outcomes vary depending on factors, including tumor phenotype, extent of disease within and outside the brain, as well as patient performance status. Treatment includes surgery, radiation therapy and systemic therapy determined by patient and tumor characteristics. Despite these approaches, novel treatments are needed and there is growing interest in systemic therapies. However, the efficacy of pharmacologic agents is hampered by poor penetration of drugs across the blood–brain barrier. Therefore, there is a pressing need for a greater understanding of the natural history of BCBM to guide the development of further therapies. This review analyzes prognosis and treatment of BCBM by tumor phenotype and discusses ongoing research into new therapies.     

Development of sorafenib and other molecularly targeted agents in hepatocellular carcinoma

It is well appreciated that hepatocellular carcinoma (HCC) represents one of the most challenging malignancies of worldwide importance. In fact, HCC is the fifth most common cancer and the third most common cause of cancer-related death globally. The incidence rates for HCC in the U.S. and Western Europe have been rising. Unresectable or metastatic HCC carries a poor prognosis, and systemic therapy with cytotoxic agents provides marginal benefit. Because of the poor track record of systemic therapy in HCC, there has been a sense of nihilism for this disease in the oncology community for decades. However, with the arrival of newly developed, molecularly targeted agents and the success of some of these agents in other traditionally challenging cancers, such as renal cell carcinoma, there has been renewed interest in developing novel systemic therapy in HCC. At the recent Annual Meeting of the American Society of Clinical Oncology, results of a phase 3, randomized, placebo-controlled trial were presented in which sorafenib demonstrated improved survival in patients with advanced HCC. This landmark study represents the first agent that has demonstrated an improved overall survival benefit in this disease and sets the new standard for first-line treatment of advanced HCC. For this review, the author concisely summarized the current status of molecularly targeted agents that are under clinical development in advanced HCC.     

Targeted therapy for hepatocellular carcinoma: novel agents on the horizon

Hepatocellular carcinoma (HCC) is the most common liver cancer, accounting for 90% of primary liver cancers. In the last decade it has become one of the most frequently occurring tumors worldwide and is also considered to be the most lethal of the cancer systems, accounting for approximately one third of all malignancies. Although the clinical diagnosis and management of early-stage HCC has improved significantly, HCC prognosis is still extremely poor. Furthermore, advanced HCC is a highly aggressive tumor with a poor or no response to common therapies. Therefore, new effective and well-tolerated therapy strategies are urgently needed. Targeted therapies have entered the field of anti-neoplastic treatment and are being used on their own or in combination with conventional chemotherapy drugs. Molecular-targeted therapy holds great promise in the treatment of HCC. A new therapeutic opportunity for advanced HCC is the use of sorafenib (Nexavar). On the basis of the recent large randomized phase III study, the Sorafenib HCC Assessment Randomized Protocol (SHARP), sorafenib has been approved by the FDA for the treatment of advanced HCC. Sorafenib showed to be able to significantly increase survival in patients with advanced HCC, establishing a new standard of care. Despite this promising breakthrough, patients with HCC still have a dismal prognosis, as it is currently the major cause of death in cirrhotic patients. Nevertheless, the successful results of the SHARP trial underscore the need for a comprehensive understanding of the molecular pathogenesis of this devastating disease. In this review we summarize the most important studies on the signaling pathways implicated in the pathogenesis of HCC, as well as the newest emerging drugs and their potential use in HCC management.     

Roles of conventional and complementary therapies in recurrent hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common type of cancer and the fourth leading cause of cancer-related deaths in the world. HCC has a reported recurrence rate of 70%-80% after 5 years of follow-up. Controlling tumor recurrence is the most critical factor associated with HCC mortality. Conventional salvage therapies for recurrent HCC include re-hepatectomy or liver transplantation, transcatheter arterial chemoembolization, Y-90, target therapy, and immunotherapy; however, these conventional treatment modalities have yet to achieve consistently favorable outcomes. Meanwhile, previous studies have demonstrated that conventional therapies in combination with traditional Chinese medicine (TCM), acupuncture, moxibustion or dietary supplements could notably benefit patients with HCC recurrence by strengthening and augmenting the overall management strategy. However, systemic reviews related to the interactions between complementary therapies and conventional therapy in recurrent HCC are limited. In this review, we discuss the molecular mechanisms underlying the functions of complementary therapies for recurrent HCC, which include augmenting the local control to improve the congestion status of primary tumors and reducing multicentric tumor occurrence via inducing autophagy, apoptosis or cell cycle arrest. TCM and its derivatives may play important roles in helping to control HCC recurrence by inhibiting epithelial-mesenchymal transition, migration, invasion, and metastasis, inhibiting cancer stem cells, and ameliorating drug resistance.     

Improving delivery of antineoplastic agents with anti-vascular endothelial growth factor therapy

It is believed that impairments in delivery of antineoplastic agents to solid tumors result from abnormalities of the tumor microenvironment. Vascular endothelial growth factor (VEGF), the prototypical angiogenic molecule, is one of the main factors responsible for the development and maintenance of the aberrant tumor vascular network, which is characterized by chaotic, leaky blood vessels with high interstitial fluid pressure and inefficient blood flow. The authors proposed that anti-VEGF therapy would reduce the elevated interstitial fluid pressure in tumors, thereby improving blood flow and potentially improving delivery of cytotoxic agents to tumor cells. For the current report, the authors reviewed characteristics of the abnormal tumor vasculature created under the influence of VEGF, the resulting tumor microenvironment, how the tumor microenvironment may impede delivery of antineoplastic agents, and how the combination of anti-VEGF and cytotoxic therapy may maximize the efficacy of antineoplastic treatment regimens.     

Hepatitis C and hepatocellular carcinoma

Chronic hepatitis C infection (HCV) accounts for approximately 50% of the cases of hepatocellular carcinoma (HCC) in the United States. Cirrhosis or an advanced stage of fibrosis is the major risk factor of HCC; patients with cirrhosis are recommended to undergo surveillance with alpha-fetoprotein and ultrasound. Alpha interferon (IFN-alpha) is associated with a reduced risk of HCC in patients with chronic infection but insufficient data exist to recommend treatment of patients with cirrhosis and HCV for this reason alone. Resection and liver transplantation are the only "curative" therapies available. Advanced fibrosis or cirrhosis in patients with HCC limits the number of patients for whom resection is applicable. Moreover, the remaining liver is at high risk of developing a second primary tumor. Partial hepatic resection for hepatocellular carcinoma should be restricted to patients with well-compensated cirrhosis (Child's A class). Acceptable parameters include a single lesion not exceeding 5 cm, normal levels of bilirubin, and absence of portal hypertension. Liver transplantation is the best definitive treatment for HCV-infected patients who have small, localized HCC (solitary lesion not greater than 5 cm, or no more than 3 lesions, none of which are greater than 3 cm). Limitations of liver transplantation as a therapy for HCC are the scarcity of donor organs and the prolonged waiting time during which continued tumor growth occurs. Living donors can reduce waiting time and increase the number of patients treatable by transplantation. Chemoembolization and local ablation therapies have not been shown to confer survival benefits as primary treatments for HCC. The potential benefit of these procedures in controlling tumor growth to "bridge" patients to liver transplantation must be further investigated. Similarly, systemic chemotherapy and hormonal therapy do not generally produce a survival advantage. However, recent studies that used octreotide and combination doxorubicin/cisplatin/5-FU/interferon appear to be promising.     

A long-term survival case of hepatocellular carcinoma with portal vein and inferior vena cava tumor thrombi

We report a case of advanced hepatocellular carcinoma (HCC) successfully treated by hepatic arterial infusion of 5-fluorouracil (5-FU) combined with systemic administration of interferon (IFN)-α and trans-arterial infusion (TAI) therapy of cisplatin (CDDP). A case was a 60-year-old man who had right upper abdominal pain and back pain. The abdominal CT revealed an early enhanced lesion in the posterior segment of the liver with portal vein and inferior vena caval tumor thrombi and multiple intrahepatic metastases. Tumor markers were elevated, AFP 2,480 ng/mL, PIVKA-II 31,900 mAU/mL. The patient underwent 4 courses of IFN-α/5-FU combination therapy and 8 times of TAI therapy of CDDP. After these therapies, tumors in the liver disappeared and tumor markers returned to the normal range. The patient is alive more than 58 months after the initial treatment. This case suggests that some patients with advanced HCC with tumor thrombus can get a long-term survival when intrahepatic lesions are controlled by various therapies including IFN-α/5-FU combination therapy.     

Uveal melanoma

Uveal melanoma, which arises from melanocytes residing in the stroma, is the most common primary intraocular tumor in adults. Up to 50% of patients with primary uveal melanoma will ultimately develop distant metastasis, the liver being involved in up to 90% of individuals and the median survival reported to be 4-5 months. The current treatment of metastatic uveal melanoma is limited by the lack of effective systemic therapy. The intrinsic resistance of uveal melanoma to conventional systemic chemotherapy has led researchers to evaluate new approaches. Molecular biology and a better knowledge of cancer cells allowed the development of target therapies: these refer to drugs designed to interact with a specific molecular pathway known to have a critical role in tumor growth or progression. Several drugs, such as bevacizumab, imatinib and MEK-inhibitors, are currently under investigation as single agents or in combination with chemotherapeutic drugs for the treatment of metastatic uveal melanoma. Finally, ipilimumab, which targets the immune compartment, was reported to increase overall survival in cutaneous melanoma patients, with preliminary evidence of similar activity in ocular melanoma.