Arteriovenous malformation is an abnormal connection between arteries and veins, bypassing the capillary system. This vascular anomaly is widely known because of its occurrence in the central nervous system, but can appear in any location. Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems.
Chemotherapy is a type of cancer treatment that uses one or more anti-cancer drugs as part of a standardized chemotherapy regimen. Chemotherapy may be given with a curative intent, or it may aim to prolong life or to reduce symptoms. Chemotherapy is one of the major categories of the medical discipline specifically devoted to pharmacotherapy for cancer, which is called medical oncology.
Interventional radiology (IR) is a medical subspecialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
Hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel. It is the first stage of wound healing. This involves coagulation, blood changing from a liquid to a gel. Intact blood vessels are central to moderating blood's tendency to form clots. The endothelial cells of intact vessels prevent blood clotting with a heparin-like molecule and thrombomodulin and prevent platelet aggregation with nitric oxide and prostacyclin. When endothelial injury occurs, the endothelial cells stop secretion of coagulation and aggregation inhibitors and instead secrete von Willebrand factor, which initiate the maintenance of hemostasis after injury. Hemostasis has three major steps: 1) vasoconstriction, 2) temporary blockage of a break by a platelet plug, and 3) blood coagulation, or formation of a fibrin clot. These processes seal the hole until tissues are repaired.
Embolization refers to the passage and lodging of an embolus within the bloodstream. It may be of natural origin (pathological), in which sense it is also called embolism, for example a pulmonary embolism; or it may be artificially induced (therapeutic), as a hemostatic treatment for bleeding or as a treatment for some types of cancer by deliberately blocking blood vessels to starve the tumor cells.
Transcatheter arterial chemoembolization (TACE) is a minimally invasive procedure performed in interventional radiology to restrict a tumor's blood supply. Small embolic particles coated with chemotherapeutic drugs are injected selectively through a catheter into an artery directly supplying the tumor. These particles both block the blood supply and induce cytotoxicity, attacking the tumor in several ways.
Carcinoid syndrome is a paraneoplastic syndrome comprising the signs and symptoms that occur secondary to carcinoid tumors. The syndrome includes flushing and diarrhea, and less frequently, heart failure, vomiting and bronchoconstriction. It is caused by endogenous secretion of mainly serotonin and kallikrein.
Mitomycin C is a mitomycin that is used as a chemotherapeutic agent by virtue of its antitumour activity
Tirapazamine (SR-4233) is an experimental anticancer drug that is activated to a toxic radical only at very low levels of oxygen (hypoxia). Such levels are common in human solid tumors, a phenomenon known as tumor hypoxia. Thus, tirapazamine is activated to its toxic form preferentially in the hypoxic areas of solid tumors. Cells in these regions are resistant to killing by radiotherapy and most anticancer drugs. Thus the combination of tirapazamine with conventional anticancer treatments is particularly effective. As of 2006, tirapazamine is undergoing phase III testing in patients with head and neck cancer and gynecological cancer, and similar trials are being undertaken for other solid tumor types.
The enhanced permeability and retention (EPR) effect is a controversial concept by which molecules of certain sizes tend to accumulate in tumor tissue much more than they do in normal tissues. The general explanation that is given for this phenomenon is that, in order for tumor cells to grow quickly, they must stimulate the production of blood vessels. VEGF and other growth factors are involved in cancer angiogenesis. Tumor cell aggregates as small as 150–200 μm, start to become dependent on blood supply carried out by neovasculature for their nutritional and oxygen supply. These newly formed tumor vessels are usually abnormal in form and architecture. They are poorly aligned defective endothelial cells with wide fenestrations, lacking a smooth muscle layer, or innervation with a wider lumen, and impaired functional receptors for angiotensin II. Furthermore, tumor tissues usually lack effective lymphatic drainage. All of these factors lead to abnormal molecular and fluid transport dynamics, especially for macromolecular drugs. This phenomenon is referred to as the "enhanced permeability and retention (EPR) effect" of macromolecules and lipids in solid tumors. The EPR effect is further enhanced by many pathophysiological factors involved in enhancement of the extravasation of macromolecules in solid tumor tissues. For instance, bradykinin, nitric oxide / peroxynitrite, prostaglandins, vascular permeability factor, tumor necrosis factor and others. One factor that leads to the increased retention is the lack of lymphatics around the tumor region which would filter out such particles under normal conditions.
Veterinary surgery is surgery performed on animals by veterinarians, whereby the procedures fall into three broad categories: orthopaedics, soft tissue surgery, and neurosurgery. Advanced surgical procedures such as joint replacement, fracture repair, stabilization of cranial cruciate ligament deficiency, oncologic (cancer) surgery, herniated disc treatment, complicated gastrointestinal or urogenital procedures, kidney transplant, skin grafts, complicated wound management, and minimally invasive procedures are performed by veterinary surgeons. Most general practice veterinarians perform routine surgeries such as neuters and minor mass excisions; some also perform additional procedures.
Primary tumors of the heart are extremely rare tumors that arise from the normal tissues that make up the heart. The incidence of primary cardiac tumors has been found to be approximately 0.02%. This is in contrast to secondary tumors of the heart, which are typically either metastatic from another part of the body, or infiltrate the heart via direct extension from the surrounding tissues. Metastatic tumors to the heart is about 20 times more common than primary cardiac tumors.
A myxoma is a rare benign tumor of the heart. Myxomata are the most common primary cardiac tumor in adults, and are most commonly found within the left atrium near the valve of the fossa ovalis. Myxomata may also develop in the other heart chambers. The tumor is derived from multipotent mesenchymal cells. Cardiac myxoma can affect adults between 30 and 60 years of age.
Eribulin, sold under the brand name Halaven, is an anticancer medication used to treat breast cancer and liposarcoma.
A radiosensitizer is an agent that makes tumor cells more sensitive to radiation therapy. It is sometimes also known as a radiation sensitizer or radio-enhancer.
Hepatic artery embolization, also known as trans-arterial embolization (TAE), is one of the several therapeutic methods to treat primary liver tumors or metastases to the liver. The embolization therapy can reduce the size of the tumor, and decrease the tumor's impact such its hormone production, effectively decreasing symptoms. The treatment was initially developed in the early 1970s. The several types of hepatic artery treatments are based on the observation that tumor cells get nearly all their nutrients from the hepatic artery, while the normal cells of the liver get about 70-80 percent of their nutrients and 50% their oxygen supply from the portal vein, and thus can survive with the hepatic artery effectively blocked. In practice, hepatic artery embolization occludes the blood flow to the tumors, achieving significant tumor shrinkage in over 80% of people. Shrinkage rates vary.
Interventional oncology is a subspecialty field of interventional radiology that deals with the diagnosis and treatment of cancer and cancer-related problems using targeted minimally invasive procedures performed under image guidance. Interventional oncology has developed to a separate pillar of modern oncology and it employs X-ray, ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) to help guide miniaturized instruments to allow targeted and precise treatment of solid tumours located in various organs of the human body, including but not limited to the liver, kidneys, lungs, and bones. Interventional oncology treatments are routinely carried out by interventional radiologists in appropriate settings and facilities.
Portal vein embolization (PVE) is a preoperative procedure performed in interventional radiology to initiate hypertrophy of the anticipated future liver remnant a couple weeks prior to a major liver resection procedure. The procedure involves injecting the right or left portal vein with embolic material to occlude portal blood flow. By occluding the blood flow to areas of the liver that will be resected away, the blood is diverted to healthy parts of the liver and induces hyperplasia. This may allow for a more extensive resection or stage bilateral resections that would otherwise be contraindicated resulting in better oncological treatment outcomes.
Transarterial bland embolization is a catheter-based tumor treatment of the liver. In this procedure, a variety of embolizing agents can be delivered through the tumor’s feeding artery in order to completely occlude the tumor’s blood supply. The anti-tumor effects are solely based on tumor ischemia and infarction of tumor tissue, as no chemotherapeutic agents are administered. The rationale for the use of bland embolization for hepatocellular carcinoma(HCC) and/or other hyper-vascular tumors is based on the fact that normal liver receives a dual blood supply from the hepatic artery (25%) and the portal vein (75%). As the tumor grows, it becomes increasingly dependent on the hepatic artery for blood supply. Once a tumor nodule reaches a diameter of 2 cm or more, most of the blood supply is derived from the hepatic artery. Therefore, bland embolization and transarterial chemoembolization (TACE) consist of the selective angiographic occlusion of the tumor arterial blood supply with a variety of embolizing agents, with or without the precedence of local chemotherapy infusion. The occlusion by embolic particles results in tumor hypoxia and necrosis, without affecting the normal hepatic parenchyma.
Bronchial artery embolization is a treatment for hemoptysis, abbreviated as BAE. It is a kind of catheter intervention to control hemoptysis by embolizing the bronchial artery, which is a bleeding source. Embolic agents are particulate embolic material such as gelatin sponge or polyvinyl alcohol (PVA), and liquid embolic material such as NBCA, or metallic coils.
