We tamed infections with sanitation and vaccines, abetted by antibiotics. We tamed heart disease through smoking cessation, better medical management of risk factors such as high cholesterol, and improved interventions for a condition that has clear points of intervention and responds more readily to lifestyle changes. Cancer is a different story. Even today, it continues to occupy our collective imagination as the king of terrors: insidious, capricious, relentless.
Anyone who has suffered cancer, or has suffered alongside a loved one with the disease—a considerable portion of the population, given that more than one in three of us will be diagnosed with a malignancy during our lifetime—knows the anguish and helplessness that trail the diagnosis. In , a study in Science seemed to confirm our primal fear.
It argued that only one-third of the variation in cancer risk in tissues is due to environmental assaults or inherited genetic predispositions. Cell division is an imperfect process; like a biological keyboard with a letter missing, it makes mistakes.
For that reason, it is unlikely that cancer could ever be eradicated. The reality of cancer lies somewhere between the public health ideal of perfect prevention and the depressing stochastics of bad luck. Current research suggests that at least half of cancer cases—estimates range from 30 percent to upward of 70 percent—could be prevented by applying what we already know.
The other half of cancer cases—including the elusive and often deadly types often caught too late to make a difference, such as ovarian, pancreatic, and brain tumors—could be detected and potentially even prevented far earlier if basic science and promising diagnostic technologies received the sustained government support they need.
Put simply, cancer must be framed not just as a curable disease but equally as a preventable one. Gregory, Jr. Professor of Cancer Prevention at the Harvard T. In order to make a dent in a public health sense, we must prevent cancer. In , according to the American Cancer Society, an estimated 1,, people will be diagnosed with cancer in the United States and an estimated , will die of the disease.
Globally, cancer killed an estimated 9. In this century, cancer will become not only the leading cause of death worldwide in 91 nations it already ranks as the first or second cause of death before age 70, according to the World Health Organization but also the single biggest hurdle to boosting life expectancy in scores of nations.
Part of the trend is demographic: The human population is both growing and aging each year, meaning more people are vulnerable to the disease, which takes advantage of the waning immune system and the accumulated DNA damage that accompanies aging.
While smoking is down in the United States, for example, it is up in Africa and the Eastern Mediterranean, as tobacco companies expand into new markets. And while cigarette use is the most important risk factor for cancer worldwide, cancer-causing infections, such as hepatitis and the human papilloma virus HPV —both preventable with vaccines—account for up to 25 percent of cancer cases in some low- and middle-income countries. These shifting sands of causation are also evident in the United States.
Over the past 25 years, while cancer deaths have risen in number as the population grows, the cancer death rate has steadily declined. As of , the cancer mortality rate for men and women combined had fallen 27 percent from its peak in The engine behind this impressive public health feat was the decline in smoking, though early detection and improved treatments also played a role.
In , 42 percent of U. Lung cancer death rates declined in tandem, falling 48 percent from to among men and 23 percent from to among women. That public health victory is now in peril. In the next five to 10 years, experts say, the cancer-causing effects of obesity could actually reverse the downward trend ushered in by the decline in smoking.
Indeed, obesity could soon become the number-one risk factor for cancer in the United States and eventually around the world. In the U. Obesity is a well-established risk factor for at least 13 cancers. Increasing obesity among younger people may portend a bigger wave of cancer in the near future, according to the The Lancet Public Health study.
These cancer cases serve as sentinels for future disease in older people. Two kinds of prevention can substantially reduce cancer deaths. The first, and most important, is primary prevention: averting a malignancy by attacking its causes and promoting the factors that protect against it.
Taxes on cigarettes and alcohol, vaccination against cancer-causing pathogens such as HPV and hepatitis B, promoting healthy eating and regular exercise: All are examples of primary prevention.
Primary prevention works when social and economic conditions, the built environment, and the public health and medical systems work in concert to support it.
Secondary prevention has helped bring down death rates of breast, cervical, and colorectal cancers, among others. Long-term epidemiological studies have clarified which cancers are preventable and by how much, if specific risk factors were reduced.
It noted that for cancers in which most of the driving genetic mutations are caused by the environment—such as lung cancers, melanomas, and cervical cancers—85 to percent of new cases could be eliminated through smoking cessation, avoidance of ultraviolet radiation exposures, and vaccination against HPV, respectively. Even individuals at high inherited genetic risk for cancer can benefit from lifestyle change, adds Peter Kraft , professor of epidemiology at the Harvard Chan School.
In fact, the women who had the highest nonmodifiable risk but also kept their weight down, did not drink or smoke, and did not use menopausal hormone therapy had about the same breast cancer risk as an average woman in the general population. In fact, high-risk individuals are the people who seem to reap the biggest benefit from adopting healthy lifestyles.
Should anyone still doubt that many cancers are preventable, the inarguable proof is how the disease plays out over time and space. Cancer rates and types can starkly change within a country and starkly vary between countries. These variations are not genetic—a small minority of cancers are directly attributable to known, death-dealing DNA mutations. Rather, they reflect external—and, in principle, modifiable—risk factors. For example, lung cancer eclipsed all other cancers during most of the 20th century in the United States because per capita cigarette consumption shot up from 54 cigarettes a year in to 4, cigarettes in , then fell to 2, in The initial upward trend was powered by corporate profiteering.
The downward slope was powered by the landmark U. Another instance of a breathtaking prevention success within a country took place in the s and s in Taiwan, which saw an 80 percent decline in liver cancer rates in birth cohorts that received hepatitis B vaccination early in life.
The most common causes of liver cancer are infection with the hepatitis B virus in Africa and East Asia, and the hepatitis C virus in the U. And Australia recently reported it is on course to completely eliminate cervical cancer in the coming decades through vaccinations. The spatial dimension of cancer is equally revealing. When racial or ethnic groups migrate from one part of the world to another, their cancer risks quickly take on the local patterns. Between and , for example, numerous studies looked at cancer incidence in U.
Caucasians, immigrant groups, and matched controls. Among the populations studied were first- and second-generation Japanese immigrants, Asian American women, Vietnamese Americans, and Hmong refugees from Vietnam, Laos, and Thailand. This system allows researchers to target specific DNA sequences using an enzyme and a modified piece of nucleic acid.
The enzyme removes the DNA sequence, allowing it to be replaced with a customized sequence. In the prospective clinical trial, the investigators propose to use CRISPR technology to modify T cells in people with advanced myeloma, melanoma, or sarcoma. Meet some of the researchers who are working to make gene editing a reality. Many types of viruses destroy their host cell as part of their life cycle.
This makes viruses an attractive potential treatment for cancer. Virotherapy is the use of viruses to selectively kill cancer cells. The viruses used in virotherapy are called oncolytic viruses. Experts believe that when an oncolytic virus kills a cancer cell, cancer-related antigens are released. Antibodies can then bind to these antigens and trigger an immune system response. While researchers are looking at the use of several viruses for this type of treatment, only one has been approved so far.
The body naturally produces hormones, which act as messengers to the tissues and cells of your body. Hormone therapy involves using a medication to block the production of hormones. Some cancers are sensitive to the levels of specific hormones. Changes in these levels can affect the growth and survival of these cancer cells. Lowering or blocking the amount of a necessary hormone can slow the growth of these types of cancers.
Hormone therapy is sometimes used to treat breast cancer , prostate cancer, and uterine cancer. Nanoparticles are very tiny structures. Their size allows them to move throughout the body and interact with different cells and biological molecules.
Nanoparticles are promising tools for the treatment of cancer, particularly as a method for delivering drugs to a tumor site. This can help make cancer treatment more effective while minimizing side effects. While that type of nanoparticle therapy is still largely in the development stage, several nanoparticle-based delivery systems are approved for the treatment of various types of cancer.
Other cancer treatments that use nanoparticle technology are currently in clinical trials. The world of cancer treatment is constantly growing and changing.
Stay up to date with these resources:. Research on whether talcum powder causes cancer is mixed, with some studies demonstrating only a small increase in risk of certain cancers. Learn more. Galleri is a new blood test that has the ability to detect 50 types of cancer through a single blood draw.
Select U. How can antibiotics work against cancer? All of these maladies are characterized by the uncontrolled production of cells. Malignant cells reproduce and form tumors or, in the case of blood cancers, crowd out normal cells in bone marrow and the bloodstream. People are diverse, and cancers are too. Two types of cancer might occur in the same organ, but they might not behave or react to treatment in the same way.
And genetic makeup can further complicate detection, diagnosis, and treatment. Despite all of the challenges that cancer presents, researchers are making progress in the prevention, detection, treatment, and survivorship of the disease. Maybe more lives have been saved by public education and subsequent changes in behaviors than what people like me do in the lab. Prevention is always important, of course. But so is finding newer and better treatments. And how cancer is treated has changed dramatically.
Immunotherapy , for example, has marked a huge breakthrough in cancer care.
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