b
Millions of cases of cancer are diagnosed worldwide each year. And, although it may be difficult to read, a significant portion of these risks could be avoided by changing certain daily habits. There is no magic bullet for protecting oneself against cancer, but science is very clear on one thing: our lifestyle, the environment in which we live, and certain biological factors can either increase or decrease the risk of developing it.
Understand what the risk factors for cancer are, see clear examples, and know how to reduce them. It gives us room to maneuver and make more informed decisions. It's not about living in fear, but about playing to our best advantage: eating better, moving more, avoiding tobacco and excessive alcohol, protecting our skin from the sun, getting vaccinated against certain infections, and going for regular medical checkups.
What is a cancer risk factor and how is it identified?
A cancer risk factor is any characteristic, exposure, or habit that increases the likelihood of developing a tumor.There are people with many risk factors who never develop cancer, and others who suffer from it without having any apparent risk factors, but the more these factors accumulate, the more the balance tips towards the disease.
Researchers detect these risk factors primarily through epidemiological studies.These studies compare large groups of people with cancer to people without the disease. They analyze differences in lifestyle, environment, workplace, family history, and medical history to see what patterns are repeated.
When several studies find the same association and, in addition, there is a logical biological mechanism that explains it (For example, a substance that damages DNA or an infection that causes chronic inflammation), the scientific community gains confidence that it's not a coincidence. From there, these factors can become part of official prevention recommendations.
It is important to distinguish between modifiable and non-modifiable risk factors.The former depend largely on our habits and environment (tobacco, alcohol, diet, ultraviolet radiation, infections, sedentary lifestyle, etc.), while the latter cannot be changed, such as age, sex, or certain inherited mutations. The goal is clear: to minimize those factors within our control to compensate for those we cannot avoid.
There are also so-called protective factors.That is, behaviors or characteristics that decrease the probability of developing cancer: a diet rich in fruits and vegetables, regular physical activity, a healthy weight, vaccination against certain viruses or adequate sun protection, among others.
Tobacco: the main modifiable risk factor
Tobacco remains the most potent and preventable cancer risk factor on the planetIt is estimated to cause around 14% of all cancer cases and 20% of cancer deaths in some countries, especially lung cancer, which is the deadliest cancer both globally and nationally.
Smoking is not only linked to lung cancerIt also increases the risk of tumors of the mouth, pharynx, larynx, esophagus, liver, pancreas, bladder, kidney, stomach, cervix, colon, and rectum, among others. Chewing tobacco and other smokeless tobacco products are not harmless either: they are linked to cancers of the oral cavity, throat, and pancreas.
The reason is that tobacco smoke contains more than 5.000 chemical substances, at least 70 of which are clearly carcinogenic. (such as certain nitrosamines or benzene). These molecules directly damage the DNA of cells and hinder their repair, promote persistent chronic inflammation, and can cause epigenetic changes, that is, turn genes involved in tumor development on or off.
Continuing to smoke after a cancer diagnosis also clearly worsens the prognosisTobacco has been shown to increase the toxicity of treatments such as radiotherapy and chemotherapy, reduce their effectiveness, increase side effects, and is associated with lower overall survival and a higher likelihood of relapse in lung, head and neck, breast, or colon cancers.
We must not forget the role of other people's smokePassive exposure to tobacco smoke has been linked to an increased risk of lung, breast, and other cancers, as well as complicating the clinical course in those already affected. Quitting smoking, even after a diagnosis, significantly reduces the likelihood of recurrence and improves disease-free survival, so it's never "too late" to quit.
Alcohol: a carcinogen for multiple organs
Alcohol is recognized as a direct carcinogen which influences everything from the appearance of the tumor to its behavior after diagnosis. There is a clear dose-response relationship: the more grams of alcohol consumed per day and for more years, the greater the risk of developing cancer.
Even amounts considered “moderate” can increase the riskespecially breast and colon cancer. Among the tumors most closely linked to alcohol consumption are those of the mouth, pharynx, larynx, esophagus, liver, colon, rectum, and breast. Some international studies attribute approximately 1 in 25 cancer diagnoses to alcohol consumption.
The key mechanism involves acetaldehydeThis is an intermediate product of ethanol metabolism that directly damages DNA and generates oxidative stress in cells. In addition, it activates pro-inflammatory pathways and causes certain hormonal alterations, such as increased estrogen levels in women, which are linked to a higher risk of breast cancer.
In people with cancer, continuing to drink contributes to worsening the condition. liver function and drug metabolismincreasing the toxicity of chemotherapy and other systemic therapies. Conversely, reducing or eliminating alcohol after diagnosis has been associated with better survival and fewer relapses, especially in breast and colon cancers.
In practice, the most prudent recommendations aim to limit alcohol consumption as much as possible or, ideally, eliminate it altogether.Any reduction helps, but the data shows that there is no completely "safe" level of consumption with regard to cancer risk, however normalized alcohol may be in social life.
Obesity, body weight and cancer
Excess weight and obesity are now the second leading preventable cause of cancerSecond only to tobacco, they have been linked to at least 13 types of tumors, including those of the colon, postmenopausal breast, endometrium, kidney, esophagus, liver, pancreas, gallbladder, ovary, and thyroid, as well as multiple myeloma.
A body mass index (BMI) between 18,5 and 24,9 is considered healthyFrom age 25 (overweight), the risk of certain cancers increases progressively, and even more so when one enters the obese range. We're not just talking about the risk of developing cancer: weight also impacts the likelihood of a cure and long-term survival.
Excess fatty tissue promotes a state of chronic low-grade inflammationIt alters the metabolism of hormones such as estrogen and insulin, and modifies growth factors involved in cell proliferation. In colorectal cancer, for example, a clear relationship between obesity and a higher probability of developing the tumor has been consistently demonstrated.
Obesity also makes early diagnosis more difficult and complicates treatmentsIn overweight individuals, the detection of masses or changes during physical examination may be delayed, and tests such as mammograms or certain surgeries may be more complex. Some treatments, such as radiation therapy or chemotherapy, may be less effective or have a higher rate of complications.
Studies suggest that sustained weight loss improves the response to treatmentsIt reduces the risk of relapse and decreases cancer mortality in tumors closely linked to obesity, such as breast and colon cancer. Maintaining a healthy weight is not just about aesthetics, but a direct investment in cancer prevention and better treatment tolerance should the disease develop.
Nutrition and protective dietary patterns
The way we eat daily can prevent between 30 and 40% of cancer casesespecially of the digestive tract and, in particular, colorectal cancer. There is no "miracle" food that cures or causes cancer on its own, but there are dietary patterns that clearly increase or decrease the risk.
Diets rich in fruits, vegetables, legumes, and whole grainsA diet rich in healthy fats (extra virgin olive oil, nuts, oily fish) and moderate consumption of animal protein is associated with a lower risk of several cancers. This type of diet, exemplified by the Mediterranean diet, has anti-inflammatory and antioxidant effects and improves the metabolic profile.
Conversely, a pattern with abundant red and processed meats, ultra-processedadded sugars and refined flours It has been linked to an increased risk of cancer, especially colorectal cancer. Cooking meat at high temperatures (very hot griddle, barbecue) generates compounds such as heterocyclic amines and polycyclic aromatic hydrocarbons, which have carcinogenic potential.
Dietary fiber plays a particularly protective roleConsuming about 25-30 g of fiber per day is associated with up to a 15-20% lower risk of colon cancer. Fiber helps regulate bowel movements, reduces the contact time of potential carcinogens with the colon's lining, and promotes a healthier gut microbiota.
Certain compounds present in plant-based foods appear to offer an added benefit.such as sulforaphane in broccoli or the polyphenols in green tea and berries. These compounds can modulate cell proliferation pathways, reduce oxidative stress, and enhance the body's defense mechanisms. Several studies have shown particular benefits in cancers such as breast cancer.
In cancer patients, good nutritional status also makes a differenceA balanced diet helps preserve muscle mass, reduces the toxicity of treatments, shortens recovery time after surgery, and improves quality of life by decreasing fatigue and other side effects. Guidelines recommend, among other measures, at least five servings of fruits and vegetables a day (about 400 g), choosing whole grains, limiting red meat to less than 200 g per week, and avoiding processed meat and sugary ultra-processed foods.
Physical activity, sedentary lifestyle and cancer risk
Physical inactivity and prolonged sedentary behavior have become established as relevant risk factors for cancer.. The regular physical activityHowever, it reduces the risk of more than a dozen types of tumors, including colon, breast, endometrium, kidney and esophagus.
More active people may have up to a 25% lower risk of breast cancer than the most sedentary. In studies based on daily steps, those who take around 7.000 steps a day show about an 11% lower risk of cancer than those who only reach 5.000, and those who reach about 9.000 steps reduce it by around 16%.
The benefits of exercise go far beyond weight controlMovement helps regulate sex hormones (estrogens, androgens) and growth factors, decreases insulin and improves its sensitivity, reduces systemic inflammation, enhances the immune system response and accelerates intestinal transit, reducing the contact of the mucosa with possible carcinogens.
The other side of the coin is sedentary lifestyleSpending many hours a day sitting has been associated with an increased risk of up to 66% for some tumors (such as colon and endometrium), and with an 82% increase in the risk of cancer mortality in the most inactive individuals, according to studies by major international cancer centers.
For people who have already overcome cancer, exercise also marks a turning point.Structured physical activity programs following treatment for tumors such as colon cancer have been shown to reduce the likelihood of relapse and improve disease-free survival. Furthermore, strength training and maintaining muscle mass appear to limit the toxicity of certain drugs (such as cisplatin) and improve tolerance to chemotherapy and radiotherapy.
Ultraviolet radiation, gases, and other environmental factors
Ultraviolet (UV) radiation from the sun and tanning beds is a key risk factor for skin cancerincluding melanoma, basal cell carcinoma, and squamous cell carcinoma. It is estimated that nearly 9 out of 10 melanomas could be prevented with responsible sun exposure.
UV radiation causes direct damage to the DNA of skin cellsIt increases cellular stress, promotes chronic inflammation, and partially inhibits local immune surveillance. The skin has a "memory": damage accumulates from childhood, so repeated sunburns in early life are recorded and increase the risk of developing cancer decades later.
Basic recommendations for protect yourself from the sun They are clear and simpleAvoid sun exposure during the peak hours of the day (approximately 12:00 to 16:00), use broad-spectrum sunscreens with a high SPF (at least 30-50), reapply them every two hours and after swimming or sweating, and cover up with clothing, hats, and sunglasses. Tanning beds should be avoided altogether, as they emit enough UV radiation to increase the risk of melanoma.
In addition to solar radiation, other environmental factors also play a role.Prolonged exposure to certain air pollutants and gases, such as radon, has been associated primarily with an increased risk of lung cancer. Radon is a naturally occurring radioactive gas that originates underground and can accumulate in poorly ventilated homes and buildings.
The particles released by radon can damage the DNA of lung cells.It generates oxidative stress and contributes to sustained inflammation, all of which are linked to the development of tumors. Although its exact impact is still being investigated in depth, it is considered a significant carcinogen, especially when combined with tobacco, which multiplies the risk.
Infections and cancer: viruses, bacteria and parasites involved
It is estimated that around 5% of cancers are due to chronic infections. caused by viruses, bacteria, or parasites. These infections generate sustained inflammation, alter cellular processes, and, in some cases, produce proteins that directly transform cells into tumors.
Among the most relevant agents is the human papillomavirus (HPV)HPV is responsible for almost 90% of cervical and anal cancers, and a significant proportion of tumors of the penis, vulva, vagina, and oropharynx. HPV proteins interfere with the mechanisms that control the cell cycle and DNA repair.
The bacterium Helicobacter pylori is linked to 75-76% of gastric cancers and with some stomach lymphomas. It often goes unnoticed, mistaken for simple indigestion, while it damages the gastric mucosa and the DNA of cells, promoting progression to precancerous lesions and, ultimately, cancer.
The hepatitis B and C viruses (HBV and HCV) cause chronic inflammation of the liverwhich can lead to cirrhosis and hepatocellular carcinoma. Other viruses, such as Epstein-Barr virus (EBV) or Kaposi's sarcoma-associated herpesvirus (HHV-8), are linked to lymphomas and sarcomas, especially in immunocompromised individuals. Parasites, such as Schistosoma haematobium (bladder cancer) or Opisthorchis viverrini (bile duct cancer), are also implicated in certain regions of the world.
The tools to reduce these risks are well defined: vaccination against HPV in adolescence (prevents almost 100% of precancerous lesions of the cervix) and against hepatitis B (drastically reduces the incidence of liver cancer), screening and treatment of infections such as HCV or H. pylori in risk groups, use of condoms, sexual education and adequate hygiene measures.
Non-modifiable risk factors: age, genetics, and others
There are risk factors that we cannot change, but that are useful to know in order to adjust the level of surveillance.Age is one of them: most cancers are more frequent as we get older, because cells accumulate DNA damage and some repair mechanisms become depleted.
Genetics and family history also play a role.It is estimated that between 5 and 10% of tumors are due to inherited mutations that significantly increase the likelihood of developing certain types of cancer. This is the case with mutations in the BRCA1 and BRCA2 genes (which increase the risk of breast and ovarian cancer) or Lynch syndrome (associated with colorectal, endometrial, and other cancers).
Not all cases of cancer in a family involve a hereditary syndrome.However, a pattern of several family members affected by the same tumor, or at unusually young ages, warrants specialist evaluation. In these contexts, genetic testing and more intensive monitoring strategies, or even preventive surgery in some specific cases, may be considered.
Sex and ethnicity also play a role.Some cancers are exclusive to one sex (prostate in men, ovarian in women) or much more frequent in one of them (breast in women, although it can also occur in men). Certain ethnic groups also show a higher incidence of certain tumors, often due to a combination of genetic, environmental, and socioeconomic factors.
Other chronic diseases increase the risk of developing tumors in certain organs.For example, inflammatory bowel disease (ulcerative colitis or Crohn's disease) increases the risk of colorectal cancer; cirrhosis, regardless of its cause, raises the risk of liver cancer; and some hormonal disorders can predispose to tumors of the thyroid, endometrium, or other tissues.
How to reduce the risk: practical prevention strategies
Although it is not possible to completely "shield" oneself from cancer, evidence indicates that up to 40-50% of cases could be prevented. Combining lifestyle changes with early detection strategies. It's not about achieving perfection, but about adding small, consistent decisions day after day.
Some practical recommendations include quitting smoking completely. (and avoid secondhand smoke), reduce alcohol to a minimum or eliminate it, follow a diet rich in fresh plant-based foods and low in ultra-processed foods, maintain a healthy weight and do at least 150 minutes of moderate aerobic physical activity per week or 75 minutes of intense activity.
It is also key to protect yourself from ultraviolet radiation with sunscreen, appropriate clothing, and by avoiding the midday sun.This includes reducing exposure to pollutants and gases as much as possible (ventilating the home, following recommendations regarding radon and other environmental agents). Vaccination against HPV and hepatitis B, and the detection and treatment of infections such as H. pylori or HCV, complete the infection-based prevention strategy.
Finally, regular medical check-ups and Recommended screening tests by age and sex They are an essential part of preventionMammograms, cytology and HPV tests, colonoscopies or fecal occult blood tests, skin examinations, or, in selected individuals, lung screening with low-dose tomography, allow for the detection of lesions in very early stages, when the chances of a cure are much higher.
Becoming aware of all these risk factors, learning about specific examples, and knowing which measures have proven effective It allows cancer prevention to be transformed into a daily commitment to health: every cigarette not lit, every extra serving of vegetables, every walk that replaces an entire afternoon sitting in front of a screen, every sunscreen properly applied or every vaccine given are small steps that, added together, tip the scales in favor of a longer and better quality life.
