There’s no foolproof way to prevent cancer or its recurrence, but following certain strategies, such as the expert-recommended advice here, can reduce risk.
Can the development of cancer be controlled?
Just about everyone wants to know what they can do to minimize their risk of getting cancer. There is no simple answer. The truth is that cancer can have myriad causes, including lifestyle choices, chemical exposure, viral or bacterial infections, hereditary predisposition and advancing age. Although individuals can’t control all these factors, they can take purposeful steps to reduce their risk.
To learn more about strategies for reducing personal cancer risk, CURE® spoke with Dr. Lifang Hou, a professor of preventive medicine and pediatrics and chief of cancer epidemiology and prevention at the Robert H. Lurie Comprehensive Cancer Center at the Feinberg School of Medicine of Northwestern University in Chicago.
“My journey as a cancer epidemiologist (is) to understand how genetic makeups that we inherited from our parents can interact with or modify the effects of our environment and lifestyles, everything we do in our daily lives that leads to cancers, and explain why people from the same family or the same parents, even identical twins, don’t develop or die from the same diseases,” she says. “My job is to connect the dots.”
Although researchers are still investigating some mysteries about risk, Hou says, solid evidence exists about other aspects of cancer prevention. Genetics can’t be changed, but lifestyle choices and environment can, forming the basis for the preventive tactics Hou recommends to both survivors and those who have never experienced cancer. As more studies are done, the public can expect to know more about which practices are most helpful and how much they can lower the odds of different cancer types.
It’s not new advice, but it’s sensible: Follow a healthy lifestyle to lower the risk of cancer. This includes not smoking, as well as reducing exposure to environmental toxins, limiting alcohol intake, eating fiber-rich fruits and vegetables, limiting red meat and processed foods, controlling calories, exercising regularly, sleeping well and avoiding stress. Checking tap water for contaminants such as arsenic and using a filter if they’re found can also be worthwhile. Hou acknowledges that some suggestions are easy to make but difficult to accomplish. For example, people who live in regions with a lot of air pollution might not want to move, or someone might know that using hair dye increases their cancer risk but not be willing to go gray. But even those who overlook a few recommendations can promote a stronger immune system by following as many as they can, she says.
“Every day, our bodies are like our computers: We have an antivirus system constantly checking for us, and if one bad guy is missed by our defensive system, that one cell can expand into a tumor,” Hou says. “So, the best thing we can really do to prevent cancer is to live a very healthy lifestyle.”
She adds that these prevention techniques are likely important prenatally, so a healthy lifestyle should start in utero.
Following the screening recommendations issued by authorities such as the National Cancer Institute and the American Cancer Society is important. As soon as eligible, an individual should get, if applicable, a mammogram to screen for breast cancer; a colonoscopy to screen for gastrointestinal cancer; blood tests to check for signs of prostate cancer; and, for those with a history of heavy smoking, a low-dose lung CT scan to screen for lung cancer. Screening tests can help identify disease in its early stages, when it’s easiest to treat and cure, Hou points out.
It’s also important that everyone get to know their own body, as conducting regular self-exams of the breasts, testicles and skin can lead to early detection of cancers. Furthermore, everyone should speak to a physician about their cancer-related concerns and family history, which could lead to personalized recommendations for earlier screening, Hou says.
A number of viral or bacterial infections can lead to the development of cancers if untreated. These viruses include hepatitis B and C, which can lead to liver cancer; HIV, which can contribute to many cancer types including Kaposi sarcoma and lymphoma; and HPV, which can lead to cancers of the cervix, vulva, vagina, penis, anus and throat. H. pylori, a very contagious bacterial infection, can lead to gastric cancer. “All these infections can be either treated or prevented, and this will really help to bring the risk for specific cancers down,” Hou says.
Many HIV-infected individuals have coinfections. “For example, more patients with HIV have HPV, hepatitis C and also tuberculosis because their immune systems are compromised,” Hou says. “For those who are not infected with HIV, we would recommend having protected, safe sexual activity.” Not sharing syringes can also help prevent both HIV and hepatitis.
There is an effective vaccine for the prevention of HPV, and it’s crucial that people secure this protection for their sons and daughters and that unvaccinated younger adults seek out the treatment for themselves, Hou says. Without the vaccine, many Americans will contract HPV, which is transmitted sexually. A vaccine against hepatitis B has been recommended since 1991 for all infants and high-risk adults.
People at high risk of any of these viral infections should request testing. This includes those who received blood transfusions or organ donations before June 1992, who may have contracted hepatitis C. In fact, some experts say that all individuals in the Baby Boomer age range should be tested for hepatitis C.
H. pylori bacteria live in the digestive tract, and people in regions where infection is common, including Asian countries, are urged not to share food or eating utensils. “If you get it, you won’t have symptoms and you won’t know,” Hou says. “I always tell my Asian friends here in the U.S. to get tested, because it’s easily treated.”
Some people have a predisposition to cancer due to inherited gene mutations, and it’s important for them to know this so they can take preventive measures. These strategies can involve screening or even surgery, such as removing the breasts or stomach.
People with a lot of close relatives who received diagnoses of cancer, particularly at younger-than-average ages, should explore whether they have an inherited predisposition. “They should definitely talk to their physicians to get a recommendation or even seek genetic counseling to see if they need genetic testing,” Hou says. “For example, mutations to the BRCA1 or BRCA2 genes can cause not only breast cancer but (also) ovarian cancer, pancreatic cancer and prostate cancer, so if people see any pattern of these particular cancers in their families, especially at younger ages, they should look for some professional advice.”
Cancer is largely an older person’s disease, but that doesn’t mean that a person’s risk will necessarily rise with chronological age. Rather, molecular age better reflects individual risk, and a younger molecular age can be maintained by making healthy lifestyle choices, such as a better diet and more exercise.
Molecular age is hard to measure, but one way to gauge it is by looking at telomeres, the caps at the ends of our chromosomes that protect our genetic material. “As we age, these caps become shorter and shorter. So, the sooner our telomeres become shorter, the more quickly our risk for cancer rises,” Hou says. “There are companies now that are measuring this.” Individuals can send blood or saliva samples directly to these companies and, based on the test results, decide whether to adjust their lifestyle habits. However, there are not yet any specific recommendations about how to interpret or act on this information.
Meanwhile, Hou’s team is working on measurements of epigenetic aging, which means looking at whether genes express themselves as if they’re young or old. “There are more than 300 biomarkers that have been found to be associated with our aging process, so our goal is to develop a comprehensive algorithm or two by taking into account several molecular age measures that can help us accurately predict molecular age,” Hou says. “A person who is only 20 can have a molecular age of 60. And the older our molecular level, the higher our risk is for cancer. This may help us identify higher-risk individuals so they can be monitored.” However, she says, this test is many years away from being available or useful to patients.
Prevention recommendations are generally the same for survivors of cancer as they are for people who have never received that diagnosis, but a difference in attitude between the two groups can affect outcomes, according to Hou. “Among those who haven’t had a cancer, most are in denial,” Hou says. “They feel that cancer is far away.” That leaves them less committed to prevention.
On the other hand, “Those who have already had a cancer have probably already discussed this with their doctors and have an awareness of cancer prevention,” Hou says. “The difference is their anxiety about recurrence. They tend to see their doctors regularly for monitoring and exactly follow what the doctor tells them. If any recurrence happens, it’s detected at a very early stage. A lot of them totally change their health and their lifestyle after the cancer. This is really about having a positive attitude.”
DR. LIFANG HOU is director of the Center for Global Oncology at the Institute for Global Health, as well as director of international affairs, at the Robert H. Lurie Comprehensive Cancer Center at the Feinberg School of Medicine at Northwestern University. She was a member of the National Cancer Institute’s Blue Ribbon Panel for the White House Cancer Moonshot Task Force, and is also a member of the Lung Cancer Screening Panel for the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology.