More than 40 years after President Richard Nixon declared a "War on Cancer," the battle is as heated as ever. Doctors, researchers, and patients are staging an all-out assault on the disease, and they're scoring some amazing victories.
Thanks to a combination of better treatments, early detection, and a commitment to prevention, more and more people are surviving cancer. According to the National Cancer Institute, death rates for lung cancer, colorectal cancer, breast cancer and prostate cancer -- the four leading causes of cancer-related deaths -- are all on the decline. Deaths from all types of cancer took a downturn in the mid-1990s -- dropping by 23 percent -- and show no sign of rising again.
Any victory celebration is premature, however: Despite much progress, cancer still kills more than 500,000 Americans every year. Researchers continue to look for ways to save more lives, and they won't stop until every cancer patient becomes a cancer survivor. With dozens of promising new treatments on the market and hundreds more in the research pipeline, the ultimate goal has never been closer.
Of course, cancer prevention is as important as ever. Diet and a sedentary lifestyle are related to about one-third percent of all cancer deaths -- and 30 percent of cancer deaths can be attributed to smoking, according to the American Cancer Society. Early screening is also important. Although some forms remain controversial, it's also true, for example, that most colon cancer deaths could be prevented with available screening tests. So among the most important fronts in the War on Cancer are probably primary prevention through behavior change, with help from simple screening tests.
Here's a look at some of the latest developments in the war on cancer:
Lowering your risk of cancer
It's well-known that exercise plays an important role in preventing heart disease. But more recently research showed that physical activity may reduce your risk of cancer as well. The best ways for nonsmoking individuals to reduce their cancer risk is to exercise regularly and eat a diet rich in fruits and vegetables and low in saturated fat, according to the American Cancer Society. The ACS recommends at least 30 minutes of moderate to vigorous physical activity five or more days a week, and even more exercise may help reduce the risks of breast and colon cancer. (Children should exercise at least an hour for five or more days a week.) You should also eat at least five servings of fruits and vegetables a day, according to the American Cancer Society.
Smoking is still the major single cause of cancer deaths in the United States, so for smokers, quitting is the best way to reduce your cancer risk.
Finally, protecting yourself against sunburn and ultraviolet rays reduces the risk of most skin cancers, including melanomas. However, experts suggest getting 15 or 20 minutes of early morning or late afternoon sun, since sunlight helps your body produce vitamin D.
Early detection of cancer can often make the difference between a treatable disease and a fatal illness. Not surprisingly, researchers are pushing to improve their ability to diagnose cancer as early as possible. They are also using the results of recent studies to fine tune guidelines for cancer screening. Here's the latest news on screening tests for common cancers:
Breast cancer. Researchers are studying new techniques for early detection of breast cancer, but mammograms are still the number one screening tool. Many experts believe that regular mammograms and early detection are largely responsible for the recent decline in breast cancer deaths.
There is some disagreement among government agencies about the ideal time to start screening. The US Preventive Services Task Force (USPSTF) recommends routine mammograms every 2 years beginning at age 50 for women at average risk of breast cancer. The task force notes that many false positives lead to unnecessary stress, anxiety and medical procedures like biopsies. There are also more false negatives in younger women, who have lower overall incidence of the disease and who have denser breasts that make mammography less sensitive.
The American Cancer Society, for its part, recommend yearly mammograms starting at age 45 and then every other year after age 55 (and recommends that women have the option to start screening at age 40 if desired). For women at high risk for breast cancer, the American Cancer Society recommends talking with their doctor to see if they should also be screened with an MRI.
Prostate cancer. For men over 50, PSA (prostate-specific antigen) tests were commonly ordered by physicians until recently, but they have declined with medical controversy over their use. This simple blood test can alert doctors to a hidden case of prostate cancer, but although the test has been around since the 1980s, surprisingly, it has never been shown to save lives. Cancers in the prostate are often slow growing and pose little threat. When the cancer is more aggressive, even early detection may not be enough to save a man's life.
The American Cancer Society recommends that doctors discuss screening all men over 50 who are expected to live for at least 10 more years and at age 45 if they are at high risk (African American or if they have a brother, father or son with prostate cancer); and at age 40 if they have more than one first-degree relative with prostate cancer. They should be informed about benefits and limitations of PSA testing and treatment (which can cause impotence and incontinence) so they can make an informed decision with their doctor about whether or not to undergo the test.
Colorectal cancer. Cancer of the rectum or colon is almost always treatable when detected early. For this reason, many experts believe that screening is an invaluable tool for preventing cancer death.
According to the American Cancer Society and other organizations, men and women at average risk for colorectal cancer should undergo regular screening for the disease starting at age 50. (People at higher risk may need to start at an earlier age.) Screening tests include a fecal immunochemical test or a fecal occult blood test (a home test that checks for small amounts of blood hidden in stool) every year; a flexible sigmoidoscopy, a double contrast barium enema or a CT colonography (virtual colonoscopy) every five years; or a colonoscopy every 10 years. (If any test besides colonoscopy is positive, doctors will then do a colonoscopy.)
There is already good evidence that early detection and removal of polyps and localized colorectal cancer can prevent a more advanced form of cancer in the vast majority of cases, and that existing screening methods can find many of these important lesions. Between 2000 and 2005, fewer than half of Americans over age 50 have had any screening -- which is probably the biggest single barrier to making a large reduction in the rates of colorectal cancer death in the U.S.
Cervical cancer. The value of the Pap test as a lifesaving, early warning system for cervical cancer is beyond dispute. In countries where Pap tests are not done, cervical cancer deaths are at least as common as deaths from breast cancer. In the U.S., 50 to 70 percent of cervical cancer deaths are in women who have not had a Pap test in the last five years. The simple test detects abnormal cells before they have a chance to turn cancerous.
The American Cancer Society recommends testing all women age 21 to 29 every three years and all other women every five years up to age 65. Testing generally isn't necessary for women who had their cervix removed in a hysterectomy (for benign disease) or for women over 65 who already had at least three normal pap smears in the last 10 years and have no other risk factors for cervical cancer.
The Food and Drug Administration (FDA) approved a new vaccine that protects against four types of HPV, including those linked to 70 percent of cervical cancer cases. The American Cancer Society now recommends routine vaccination for all girls aged 11 to 12.
Weapons against advanced breast cancer
There is good news in the treatment of advanced breast cancer, which is generally attacked with hormonal therapy, cancer-killing chemotherapy, or a combination of both.
Unlike chemotherapy, which targets cancer cells for destruction, hormonal therapy for cancer patients is designed to block the cancer cells' hormonal interactions in order to stop or slow down the proliferation of cancer cells (and potentially shrink tumors). Aromatase inhibitors act to lessen the amount of estrogen secreted by women's fat and muscle cells that would normally give a signal for cancer cells to grow when they reach their target receptors.
According to the publication CURE (Cancer Updates, Research, and Education), aromatase inhibitors are increasingly common as front-line choices for treating postmenopausal women with advanced breast cancer and can sometimes be substituted for chemo. Side effects, which can include hot flashes and joint aches, tend to be mild.
The journal CURE also had good news for regular cancer patients. "While chemotherapy previously meant side effects such as hair loss and nausea, the newer chemotherapies are kinder, gentler, and even more effective at curing or controlling disease than in the past," the journal noted.
Activating "clean-up" cells
Macrophages are white blood cells that can swallow and destroy cancer cells. Researchers have figured out how to use an antibody for a protein to activate the macrophage, which would then go into action and eliminate the cancer cells. This could lead to new and potentially less debilitating cancer treatments, researchers say.
Harnessing the power of the immune system
The human immune system has always been one of the most effective weapons against cancer. Now, scientists are working to make our natural cancer-killers even more powerful. A class of drugs called biologics fights cancer by boosting the strength of the immune system.
Vaccines are another promising approach to preventing or fighting cancer. There are currently two vaccines in use that fight viruses that can lead to cancer: the hepatitis B vaccine, which by preventing hepatitis B may also prevent some liver cancers that are due to chronic infection with the virus; and GardasilTM, which prevents infection with certain types of the human papillomavirus (HPV) that cause about 70 percent of cervical cancer cases.
And as amazing as it sounds, doctors may someday even be able to fight existing cancers with vaccines. Like shots given to ward off measles or whooping cough, cancer vaccines would be designed to help the immune system recognize and destroy rogue cells. Unlike standard vaccines, the cancer shots would be given AFTER the disease is diagnosed. Researchers are currently testing vaccines for many types of cancer. Among those being researched is a vaccine for stomach cancer, which is often associated with a bacteria called Helicobacter pylori.
Drugs that starve tumors
Another class of drugs starves tumors by blocking off their blood supply. Early trials of these drugs -- known as angiogenesis inhibitors -- were unusually successful, at least in laboratory mice. Unfortunately, human cancers proved to be much harder targets. Nonetheless, the FDA has approved several for cancer treatment, including Avastni, which has been used in the treatment of colon cancer that has spread, some non-small cell lung cancers, and breast cancers that have spread. Other angiogenesis inhibitors are now undergoing clinical trials to treat a wide range of cancers.
Lasers: The cutting edge of cancer surgery
While scalpels still have their place in operating rooms, lasers -- highly intense and precisely focused beams of light -- have recently become important tools for cancer surgery. Lasers can make extremely precise incisions and can shrink or destroy many types of tumors. Lasers are most commonly used to treat cancers in easy-to-reach places such as the skin, vocal cords, or cervix. They also can be used to shrink or destroy a tumor, for example one that is blocking a persons windpipe or esophagus, or to remove colon polyps. In some cases, endoscopes can be used to direct lasers to more out-of-the-way organs such as the lungs.
With so many new treatments and so many more on the way, these are hopeful times for cancer patients, their families, and their doctors. New treatments also mean new choices. If you've been diagnosed with cancer, you'll have to carefully consider all of your treatment options. By working with your doctor, you can do your own part in the war against cancer.
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Potential new cancer treatment activates cancer-engulfing cells. Science News. February 6, 2017.
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American Cancer Society. American Cancer Society Guidelines for the Early Detection of Cancer. March 2008.
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