A peak flow meter is a simple — yet important — asthma management tool.
A peak flow meter is a simple, easy-to-use device that measures how well your lungs are working. By measuring how efficiently you can breathe air out of your lungs, peak flow readings can help you identify worsening asthma so that you can adjust your treatment. Along with carefully watching your symptoms, you can use peak flow readings to help determine what steps you need to take to keep your asthma under control.
With time on your side, you can adjust your asthma medication and take other steps to help prevent an attack. In some cases, you may even notice changes in your peak flow before you have any signs or symptoms. A peak flow meter can be especially important if you have a hard time judging the severity of your symptoms, you have had severe asthma attacks, or you have moderate or severe asthma.
What is a monoclonal antibody?
A monoclonal antibody is a laboratory-produced molecule that can be targeted to attach to specific substances on cancer cells. Your body naturally produces antibodies as part of your immune system's response to germs and other invaders. The laboratory-produced monoclonal antibodies used in cancer treatment are carefully engineered to target specific defects in your cancer cells.
How are monoclonal antibody drugs used in cancer treatment?
Monoclonal antibody drugs were initially used to treat advanced cancers that hadn't responded to chemotherapy or cancers that had returned despite treatment. However, because these treatments have proved to be effective, certain monoclonal antibody treatments are being used earlier in the course of the disease. For instance, rituximab can be used as an initial treatment in some types of non-Hodgkin's lymphoma, and trastuzumab (Herceptin) is used in the treatment of some forms of early breast cancer.
Many of the monoclonal antibody therapies are still considered experimental. For this reason, these treatments are usually reserved for advanced cancers that aren't responding to standard, proven treatments.
| FDA-approved monoclonal antibodies for cancer treatment |
| Name of drug | Type of cancer used to treat |
| Alemtuzumab (Campath) | Chronic lymphocytic leukemia |
| Bevacizumab (Avastin) | Colon cancer
Lung cancer |
| Cetuximab (Erbitux) | Colon cancer
Head and neck cancer |
| Gemtuzumab (Mylotarg) | Acute myelogenous leukemia |
| Ibritumomab (Zevalin) | Non-Hodgkin's lymphoma |
| Panitumumab (Vectibix) | Colon cancer |
| Rituximab (Rituxan) | Non-Hodgkin's lymphoma |
| Tositumomab (Bexxar) | Non-Hodgkin's lymphoma |
| Trastuzumab (Herceptin) | Breast cancer |
Source: Food and Drug Administration, Center for Drug Evaluation and Research
Monoclonal antibodies are administered through a vein (intravenously). How often you undergo monoclonal antibody treatment depends on your cancer and what drug you're receiving. Some monoclonal antibody drugs may be used in combination with other treatments, such as chemotherapy. Others are administered alone.
How are monoclonal antibody drugs being studied?
Cancer researchers are continuing to study already-approved monoclonal antibody drugs to determine how best to use them to treat cancer. Clinical trials comparing monoclonal antibodies with other standard treatments may help doctors decide if monoclonal antibody therapy should be used sooner, rather than after other treatments have failed. These studies can also determine whether monoclonal antibodies might work best when combined with other treatments.
Cancer researchers are also working to develop new monoclonal antibodies. As they come to better understand the particular cellular changes associated with each type of cancer, researchers are discovering new targets for monoclonal antibodies.
What is gene therapy?
Put simply, gene therapy involves altering the genes inside your cells in order to stop disease. Gene therapy holds promise for treating a wide range of diseases, but the majority of trials under way are being conducted in people with cancer.
Genes are found in the cells that make up your body. They hold your DNA — the code that determines everything about you, such as your eye color and how tall you'll be. Your cells use the DNA from your genes to manufacture proteins that help translate your genetic code and set into action everything that occurs in your body, from making you grow taller to regulating your body systems. Throughout your life, your genes are turning on and off in order to control cell activity.
Cancer can result when something goes wrong with the genes in some cells. Each time a cell divides, it makes a copy of your DNA — usually an exact copy. But sometimes an error occurs. Your body has procedures in place to identify and repair those errors. When errors aren't corrected, cancer can result as the cells become unregulated and grow in an unrestricted manner as a result of their faulty genetic code.
Gene therapy targets the rogue genes by either focusing on what's going wrong in the cancer cells or enhancing the healthy cells of your immune system in a way that makes them attack your cancer.
How are cancer researchers using gene therapy?
Researchers are investigating gene therapy in a number of ways. Some examples include:
- Replacing missing or mutated genes. Some types of cancer cells grow because certain genes have been permanently shut off. Other types of cancer cells may be missing certain genes. Researchers hope that replacing missing genes or repairing altered genes will help treat cancer. For instance, a common tumor suppressor gene called p53 normally prevents tumor growth in your body. Several types of cancer have been linked to a missing or inactive p53 gene. If doctors could replace p53 where it's missing, that might trigger the cancer cells to die.
- Stopping mutated genes that enable cancer to thrive. Called oncogenes, these mutated genes could be shut off so that they no longer drive cancer growth or encourage cancer cells to spread (metastasize).
- Making cancer cells more evident to the immune system. The immune system doesn't attack cancer because, in many cases, it doesn't recognize cancer as an intruder. Cancer cells could potentially be infused with genes that make them more recognizable to the immune system. Or enhancements could be made to immune cells to make them "smarter" in recognizing cancer cells.
- Adding genes that make cancer cells more vulnerable to treatment. Because cancer cells are constantly changing and mutating, they can develop resistance to chemotherapy and radiation. Inserting genes that block this resistance could make cancer treatment more effective. In another approach, cancer cells could be given genes that make them vulnerable to a toxic drug. The drug could be administered in an inactive form, which would then become toxic only if it encountered these specific genes. That way, healthy cells wouldn't be exposed to the potentially dangerous drug.
- Preventing cancer from creating its own blood supply. Without a blood supply, tumors remain very small. Using genes to prevent or stop cancer cells from generating new blood vessels (angiogenesis) could keep a tumor small or shrink it to a manageable size.
Researchers continue to look for new genes to target. Doctors hope one day they may be able to analyze cancer cells to see exactly where an individual's cancer is vulnerable. In the future, your treatment may be tailored to the exact gene errors in your cancer cells.
What are the potential problems with gene therapy?
Gene therapy opens the possibility for unique problems. Concerns include:
- Targeting correct cells and genes. Once gene therapy treatments enter the body, doctors can't be sure that a treatment will find the right cells and place the genetic changes in the right spots. No one knows what would happen if, for instance, the wrong genes were turned on or off. Potentially, this could put you at risk of other cancers.
- Preventing genetic changes from being passed on. Researchers aren't sure if the genetic changes caused by gene therapy could be inadvertently passed on in the DNA parents give to children. It isn't clear what effects this could have.
- Using gene therapy in an ethical manner. The idea of altering genetic code makes many people uneasy. Some fear that the technology could be used unethically to, for example, alter genes within human eggs and sperm to change the eye color of a future child or attempt to enhance intelligence.
As researchers continue studying gene therapy, the potential for this treatment must be weighed against the possible problems.
Last Updated: 01/30/2008
