New treatments may rally ex-president’s fight against cancer
Jimmy Carter will have help fighting his melanoma from improved cancer drugs and therapies
Former President Jimmy Carter is battling skin cancer. And he may get some help from very recent improvements in how the disease is treated.
Carter announced on August 20 that he has melanoma (MEL-uh-NO-mah). It is a type of cancer that starts in pigment-making cells called melanocytes. Usually melanoma first shows up in the skin. But in some cases, there are no outward signs of the disease. It also can emerge in pigment cells in the eye or in mucus-making tissues inside the mouth, sinuses, anus or other areas.
Wherever the cancer started, it has now spread to his liver and brain, Carter said during a news conference.
Carter, who was president from 1977 to 1981, is 90 years old. He discovered in May that he had a slow-growing tumor on his liver. Surgery on August 3 removed the tumor and about a tenth of his liver. A test of the removed tissues showed that the tumor was melanoma. Then an MRI scan turned up four more small tumors in his brain. Each was about 2 millimeters (0.08 inch) wide.
The cancer may show up in other places, Carter said. Doctors will watch for it with scans of his body.
“Looking at his pattern of spread, you can pretty much tell that this came from the skin,” says Anna Pavlick. She’s a medical oncologist (On-KOLL-oh-gizt) at New York University’s Perlmutter Cancer Center. She is not treating Carter. He is being cared for by doctors in Atlanta. In rare melanoma cases, Pavlick says, doctors can’t find the spot on the skin where the tumors began. Carter’s cancer may be one of those cases.
Doctors may be able to use genetics to find out where the melanoma started, says Tim Turnham. He’s the executive director of the Melanoma Research Foundation in Washington, D.C. Melanoma that starts in the skin usually shows genetic signatures of DNA damage from ultraviolet light.
Scientists suspect that skin damage from the sun’s ultraviolet rays are behind most skin cancers, including melanoma.
Cases of melanoma in the United States have been increasing, especially among young people, Pavlick says. This is mostly due to the growing popularity of sun tanning — both outdoors and in tanning salons. The National Cancer Institute estimates that 73,870 people in the United States will be diagnosed with melanoma this year and that 9,940 will die.
Unlike many skin cancers, melanoma can invade and spread through the rest of the body. It’s “the cancer that knows no boundaries,” Pavlick says. Most cancers can only spread to certain other body parts. But melanoma has been known to invade gallbladders, hearts and other organs. “It just goes everywhere,” she says. “What makes it so aggressive, we just don’t understand.”
Carter will start radiation treatment for the cancer in his brain. He’s also taking a drug called pembrolizumab (PEM-broh-LIZ-uh-maab). This medicine helps hold tumor cells in check. It encourages the body to make immune cells — called T cells — that attack cancer cells. The drug also blocks markers on the surface of melanoma cells that might otherwise help them hide from the immune system. “It’s like lowering the force field around the tumor cell so that the active immune system can get in and attack it,” Pavlick explains.
Carter is lucky that his melanoma didn’t show up a few years ago. “Had he received this diagnosis five years ago, he would have had almost no treatment options available to him,” Turnham says. “The only drug available at that time was so toxic that no one would give it to someone his age.”
Recently, researchers have discovered genetic factors behind melanoma. About half of melanoma patients have a change — or mutation — in a gene called BRAF. Turning off that gene lets tumor cells grow unchecked. Drugs that fight against the mutant BRAF and other cancer genes have helped patients live longer, Pavlick says.
She has been treating melanoma patients since 1999. “For the first 10 years, all I did was sign death certificates,” Pavlick says. Recently, there have been improvements in radiation therapy, immune therapy and drugs that counteract the effects of the mutant BRAF. The result: Today about 50 percent of melanoma patients survive. And the treatments are not as difficult for patients as chemotherapy is. Predicts Pavlick, Carter will probably handle his treatments “just fine.”
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cancer Any of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.
chemotherapy A chemical treatment that’s most often used to kill cancer cells in the body. Chemotherapy can have many unpleasant side effects as it kills not only cancer cells but many healthy cells as well.
DNA (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.
gene (adj. genetic) A segment of DNA that codes, or holds instructions, for producing a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.
immune system The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.
melanocyte A type of cell that produces a dark pigment, melanin. starts in pigment-making cells called melanocytes, usually in the skin. Although best known for their presence in skin, these cells can be found elsewhere, including in the brain, eye, heart and inner ear.
melanoma A type of cancer that starts in pigment-making cells called melanocytes, usually in the skin.
magnetic resonance imaging (MRI) An imaging technique to visualize soft, internal organs, like the brain, muscles, heart and cancerous tumors. MRI uses strong magnetic fields to record the activity of individual atoms.
mutation Some change that occurs to a gene in an organism’s DNA. Some mutations occur naturally. Others can be triggered by outside factors, such as pollution, radiation, medicines or something in the diet. A gene with this change is referred to as a mutant.
oncologist A doctor who specializes in cancer.
pigment A material, like the natural colorings in skin, that alter the light reflected off of an object or transmitted through it. The overall color of a pigment typically depends on which wavelengths of visible light it absorbs and which ones it reflects. For example, a red pigment tends to reflect red wavelengths of light very well and typically absorbs other colors. Pigment also is the term for chemicals that manufacturers use to tint paint.
radiation (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.
T cells A family of white blood cells, also known as lymphocytes, that are primary actors in the immune system. They fight disease and can help the body deal with harmful substances.
tumor A mass of cells characterized by atypical and often uncontrolled growth. Benign tumors will not spread; they just grow and cause problems if they press against or tighten around healthy tissue. Malignant tumors will ultimately shed cells that can seed the body with new tumors. Malignant tumors are also known as cancers.
ultraviolet A portion of the light spectrum that is close to violet but invisible to the human eye. Ultraviolet radiation is present in sunlight and tanning booths, and can cause DNA damage leading to skin cancer.
wavelength The distance between one peak and the next in a series of waves, or the distance between one trough and the next. Visible light — which, like all electromagnetic radiation, travels in waves — includes wavelengths between about 380 nanometers (violet) and about 740 nanometers (red). Radiation with wavelengths shorter than visible light includes gamma rays, X-rays and ultraviolet light. Longer-wavelength radiation includes infrared light, microwaves and radio waves.