Understanding Cancer Risk Factors
- A new study from the American Cancer Society (ACS) has found that 40 percent of cancer cases in the U.S. have been linked to modifiable risk factors such as smoking, excess body fat, alcohol consumption, UV radiation, HPV infection and physical inactivity.
- The new findings were published in the journal CA: A Cancer Journal for Clinicians.
- Lung cancer is the leading cause of cancer deaths for men and women in the United States. Nonsmokers still get lung cancer, but cigarette smoking is the number one risk factor for the disease. Tobacco smoke contains a mixture of more than 7,000 different chemicals, at least 70 of which are known to cause cancer, the CDC says.
- While obesity or a person’s high weight will not always cause them to develop cancer, other conditions associated with obesity, like diabetes and heart disease, can lead to complications from cancer treatment if a person already has cancer. In addition, these conditions can sometimes prevent patients from receiving the recommended first-line therapies, as well as increase a patient’s risk of undergoing surgery.
- Additionally, the National Cancer Institute says there is a clear link between consuming alcohol, especially drinking it regularly over time, and an increased risk of several cancers. Those cancers include head and neck, esophageal, liver, breast and colorectal.
It's important to understand that so much of your cancer risk is beyond your control, but it's interesting to see new research from the American Cancer Society (ACS) has found that 40 percent of cancer cases in the U.S. have been linked to modifiable risk factors like smoking, alcohol consumption, excess body fat, and UV radiation. The new findings, which were published in the journal
CA: A Cancer Journal for Clinicians on Thursday, say that 20 percent of cancer cases across the country have been linked to smoking, while eight percent of cases are linked to excess body weight, according to a
news release . Additionally, 4.6 percent of cases have been linked to UV radiation, 3.1 percent linked to physical inactivity, and HPV infection linked to 1.8 percent, the findings state. ACS researchers state that four in 10 cancer cases and approximately one-half of all cancer deaths in adults age 30 and older in the U.S. could be attributed to modifiable risk factors. The lead author of the research, Dr. Farhad Islami, senior scientific director and cancer disparity research at the ACS, explained, "Despite considerable declines in smoking prevalence during the past few decades, the number of lung cancer deaths attributable to cigarette smoking in the United States is alarming. "This finding underscores the importance of implementing comprehensive tobacco control policies in each state to promote smoking cessation, as well as heightened efforts to increase screening for early detection of lung cancer when treatment could be more effective." https://twitter.com/FarhadIslami/status/1811400440267067467 Dr. Islami continued, "Interventions to help maintain healthy body weight and diet can also substantially reduce the number of cancer cases and deaths in the country, especially given the increasing incidence of several cancer types associated with excess body weight, particularly in younger individuals." The news release on the study explains that the researchers "used nationally representative data on cancer incidence and mortality and risk factor prevalence to estimate the proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors overall (excluding non-melanoma skin cancers) and for 30 cancer types." Included among the risk factors studied, were cigarette smoking [current and former smokers]; secondhand smoke; excess body weight; alcohol consumption; consumption of red and processed meat; low consumption of fruits and vegetables, dietary fiber, and dietary calcium; physical inactivity; and ultraviolet (UV) radiation. Other risk factors were infection with Epstein-Barr virus (EBV), Helicobacter pylori, hepatitis B virus (HBV), hepatitis C virus (HCV), human herpes virus-8 (HHV-8), human immunodeficiency virus (HIV), and human papillomavirus (HPV). The study
authors explain further, "By cancer type, the proportion of cases caused by potentially modifiable risk factors ranged from 100% for cervical cancer and Kaposi sarcoma to 4.9% for ovarian cancer, and exceeded 50% for 19 of 30 evaluated cancer types. In addition to cervical cancer and Kaposi sarcoma, more than 80% of all melanomas of the skin (92.2%) and cancers of the anus (94.2%), larynx (89.9%), lung and bronchus (lung; 88.2%), pharynx (87.4%), trachea (85.6%), esophagus (85.4%), and oral cavity (83.7%) were attributable to evaluated risk factors. "Lung cancer had the largest number of cases attributable to evaluated risk factors in both men (104,410 cases) and women (97,250), followed by skin melanoma (50,570), colorectal cancer (44,310), and urinary bladder cancer (32,000) in men and breast (83,840), corpus uteri (35,790), and colorectal (34,130) cancer in women." https://twitter.com/CACancerJournal/status/1811400302194475060 A senior author of the recent study, Dr. Ahmedin Jemal, senior vice president, surveillance and health equity science at the American Cancer Society, also stated that, "These findings show there is a continued need to increase equitable access to preventive health care and awareness about preventive measures. "Effective vaccines are available for hepatitis B virus, that causes liver cancer and HPV, which can cause several cancer types, including cervical, other anogenital, and oropharyngeal cancers." "Vaccination at the recommended time can substantially reduce the risk of chronic infection, and consequently, cancers associated with these viruses. HPV vaccination uptake in the United State is suboptimal," he concluded.
Smoking and Lung Cancer Risk
Lung cancer is the leading cause of cancer deaths for men and women in the United States. Nonsmokers still get lung cancer, but cigarette smoking is the number one risk factor for the disease. Tobacco smoke contains a mixture of more than 7,000 different chemicals, at least 70 of which are known to cause cancer, the
CDC says. The CDC says cigarette smoking is linked to about 80 to 90 percent of lung cancer deaths, and people who smoke cigarettes are 15 to 30 times more likely to get lung cancer or die from lung cancer than people who don’t smoke. Additionally, second-hand smoke can cause lung cancer.
WATCH: How Smokers and Non-smokers Differ Smoking is, of course, the primary cause of lung cancer, but nonsmokers can and do develop this disease. Researchers have made progress in understanding the differences between lung cancer in smokers versus nonsmokers, says
Dr. Ronald Natale , a medical oncologist at Cedars-Sinai Medical Center, and they’re developing targeted treatments that will be able to address the genetic drivers of lung cancer in nonsmokers. “Among patients who are nonsmokers, or former very light smokers, we identify a mutation that we can target with pills in about 60% to 70% of them. That leaves 30% or so, 40%, in whom we either have a target for which we do not have successful treatment,” Dr. Natale explains.
Helping You Understand the Cancer Risks from Smoking
“Among patients who are smokers, who have more complex cancers that have hundreds, sometimes thousands of mutations, don’t have a driver mutation that we can give a pill for, which is only a tiny percentage of lifelong smokers. Chemotherapy is the primary treatment in most patients."
Obesity & Your Overall Health
While obesity or a person’s high weight will not always cause them to develop cancer, other conditions associated with obesity, like diabetes and heart disease, can lead to complications from cancer treatment if a person already has cancer. In addition, these conditions can sometimes prevent patients from receiving the recommended first-line therapies, as well as increase a patient’s risk of undergoing surgery.
Dr. Andrea Tufano-Sugarman of NYU Langone Health explained to SurvivorNet the benefits of losing weight. “While all cancers cannot be prevented,” she said, “losing weight is a great way to reduce one’s risk.”
How Can Diet Affect My Cancer Risk? Dr. Tufano-Sugarman said that this is especially true for women; they lower their risk of developing breast cancer and endometrial cancer when they lose weight and keep it of. Even without losing weight, adopting a more nutritious diet can help. “Food choices, independent of weight loss, may also help to reduce risk,” Dr. Tufano-Sugarman said. “Research has shown that the Mediterranean diet (rich in fruits, vegetables, nuts and legumes, fish and olive oil) is associated with a decreased risk of cancer. Whereas diets rich in red meat may be associated with an increased risk of colorectal and prostate cancer.”
Alcohol and Cancer Risk
According to the
National Cancer Institute , there is a clear link between consuming alcohol, especially drinking it regularly over time, and an increased risk of several cancers. Those cancers include head and neck, esophageal, liver, breast and colorectal. A
study published in JAMA Network Open about two years ago found that people with “heavy drinking levels had an associated higher risk” of developing alcohol-related cancers “than those who did not drink.” The study included 4.5 million participants who self-reported their drinking habits. The results concluded people who reduced their alcohol consumption lowered their risk. Conversely, “Those with moderate or heavy drinking levels who quit drinking had a higher all cancer incidence than those who sustained their levels, but when quitting was sustained, this increase in risk disappeared.” Additionally, the
American Cancer Society warns that alcohol consumption can increase your risk for many different types of cancer. Considering cancers of the mouth, throat, voice box and esophagus, for example, alcohol “clearly” increases risk. That being said, the ACS notes that drinking and smoking together puts you at a much higher risk for these cancers than drinking or smoking alone. “This might be because alcohol can help harmful chemicals in tobacco get inside the cells that line the mouth, throat, and esophagus,” the
ACS website states . “Alcohol may also limit how these cells can repair damage to their DNA caused by the chemicals in tobacco.” When it comes to liver cancer, “
long-term alcohol use has been linked to an increased risk.” When you regularly drink a lot of alcohol, liver damage can occur and lead to inflammation and scarring a possible explanation for the increased risk.
RELATED: Alcohol Consumption Increases Cancer Risk. Less Booze Is Associated With Lower Cancer Risk, New Data Adds To The Case For Moderation We also know there’s a clear link between breast cancer and alcohol consumption. In November 2017, the American Society of Clinical Oncology
published a statement citing evidence that links alcohol to multiple cancers and calling for reduced alcohol consumption as a way to cut people’s cancer risk. But many women said they had been drinking more during the pandemic, and 70 percent weren’t aware of the resulting increased cancer risk, according to a
SurvivorNet survey in February 2021. RELATED: Warning to Drinkers: ‘Strong Link’ Found Between Alcohol and Deadly Cancers The ACS also reports that alcohol use has been linked with a higher risk of cancers of the colon and rectum with stronger evidence for this in men than in women, though studies have found the link in both sexes.
Does Alcohol Impact the Risks for Colon and Other Cancers? Dr. Heather Yeo , a colorectal cancer surgeon at New York Presbyterian/Weill Cornell Medical Center, also previously spoke with SurvivorNet, revealing she believes alcohol increases risk for certain cancers but acknowledged that the data was mixed, especially for colon cancer. “I do think that high levels of alcohol certainly predispose to a certain number of cancers, including pancreatic and liver cancer, and may predispose to colon cancer,” she said. “But there’s also some data that shows that low levels of alcohol, or a glass of wine here and there, may actually lower your risk of colon cancer.”
Contributing: SurvivorNet Staff 
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