Page 43 Complete Your CE Test Online - Click Here ● ● Slow or stop cancer cells from growing. Some targeted therapies interfere with proteins that prompt cells to divide. This helps slow a cancer’s uncontrolled growth. ● ● Stop signals that help form blood vessels. Some targeted therapies are designed to interfere with signals that trigger blood vessels to form and grow. Without a blood supply, tumors stay small. If a tumor already has a blood supply, these treatments can cause blood vessels to die, which can cause the tumor to shrink. ● ● Deliver cell-killing substances to cancer cells. Some monoclonal antibodies are bound with toxins, chemotherapy drugs, and radiation. Once the monoclonal antibodies attach to targets on the surface of cancer cells, the cells take up the cell-killing substances, causing them to die. Cells that do not have the target are typically not harmed. ● ● Cause cancer cell death. Some targeted therapies can cause cancer cells to go through the normal process of cell death. ● ● Starve cancer of the hormones needed to grow. Some breast and prostate cancers require sex hormones to grow. Hormone therapies are a type of targeted therapy that can prevent the body from making specific hormones, while others prevent the hormones from acting on cells, including cancer cells. Genetics, genomics, and treatment with targeted therapy Many targeted therapies depend on testing for tumor genetics before the treatment starts. For example, one well-known test involves looking at estrogen receptors in breast cancer to determine whether anti-estrogen compounds can help with treatment of that particular woman’s cancer. Another example from breast cancer is the overexpression of human epidermal growth factor receptors (HER2), indicating that the patient will likely benefit from using trastuzumab. Some call this “tumor profiling” and others call it individualized or personalized therapy. Tumor tissue testing is different from testing germline mutations, which are present in all the body’s cells and can be done with a blood sample. Tumor testing requires a sample of the cancerous tissue and is often done using part of the biopsy sample. This kind of testing can show whether certain targeted drugs can help stop cancer growth. Targeted therapy can cause side effects Side effects of targeted therapy depend on the drug and the patient’s responses. The most common side effects of targeted therapy include diarrhea and elevated liver function tests. Other side effects might include bleeding and delayed wound healing, high blood pressure, fatigue, mucositis, nail changes, loss of hair color, and skin problems, like rash or dry skin. Very rarely, a fistula might form through the wall of the esophagus, stomach, small intestine, large bowel, rectum, or gallbladder. Many of these side effects are treatable, and most of them fade after treatment ends [199]. Fistulas and severe diarrhea, although rare, can be life-threatening. Immunotherapy Cancer is able to grow and evolve in part because cells develop ways to elude the immune system. Immunotherapy is a type of cancer treatment that helps the immune system fight cancer. The immune system consists of lymphocytes made by: the bone marrow; the thymus; lymph nodes; spleen; tonsils; and specialized tissues in the mucous membranes of the nose, bronchi, gut, urinary tract, and other tissues. Immunotherapy is a type of biological therapy, which uses substances made from living organisms to treat cancer [171]. Types of immunotherapy Many different types of immunotherapy are used to treat cancer. They include [15,171]: ● ● Monoclonal antibodies are drugs designed to bind to specific targets in the body. They can cause an immune response that destroys cancer cells (such as pembrolizumab or nivolumab) or helps to stop them from growing (such as trastuzumab). Other types of monoclonal antibodies “mark” cancer cells so the immune system can destroy them, which is called targeted therapy (see “Targeted Therapy”). ● ● Adoptive cell transfer is a treatment that attempts to boost the ability of T cells (T-lymphocytes) to fight cancer. Researchers take T cells from the patient, isolate the T cells that are most active against the cancer or modify the genes in them to make them better able to find and destroy the cancer cells. Researchers then grow large batches of these T cells in the lab over the course of two to eight weeks. The T cells that were grown in the lab are then introduced into the patient. ● ● Cytokines are proteins that play important roles in the body’s normal immune responses and also in the immune system’s ability to respond to cancer. The two main types of cytokines used to treat cancer are called interferons (e.g. interferon alfa) and interleukins (e.g. IL-2). There are also drugs, similar to cytokines but do not occur naturally, like thalidomide and lenalidomide, that boost the immune system. ● ● Treatment vaccines work against cancer by boosting the immune response to cancer cells. The treatment vaccines are different from the ones that help prevent disease. An example of this is sipuleucel-T, which is used to treat advanced prostate cancer. ● ● BCG, Bacillus Calmette-Guérin, is an immunotherapy that is used to treat bladder cancer. It is a weakened form of the bacteria that causes tuberculosis. When injected directly into the bladder, BCG causes an immune response against cancer cells. It is also being studied in other types of cancer. Immunotherapy may be given via IV, orally, topically (for very early skin cancer, like imiquimod cream), or intravesically and it is typically given on an outpatient basis, every day, week, or month. Some immunotherapies are given in cycles [171]. Immunotherapy is not yet as widely used as surgery, chemotherapy, and radiation therapy. However, immunotherapies have been approved to treat people with many types of cancer, and many others are being studied in clinical trials [171]. Immunotherapy can cause side effects The side effects depend on the type of immunotherapy. Rarely, immunotherapies may also cause severe or even fatal allergic reactions [171]. The most common side effects are skin reactions at the needle site, such as pain, swelling, redness, or itching. They can also cause flu-like symptoms such as [171]: ● ● Fever. ● ● Chills. ● ● Weakness. ● ● Dizziness. ● ● Nausea or vomiting. ● ● Muscle or joint aches. ● ● Fatigue. ● ● Headache. ● ● Trouble breathing. ● ● Low or high blood pressure. Other side effects include: ● ● Swelling. ● ● Weight gain from fluid retention. ● ● Palpitations. ● ● Sinus congestion. ● ● Diarrhea. ● ● Risk of infection.