Why do young people get cancer even if they’re healthy?

While rates of early-onset cancer are increasing for many types of cancer (including breast, uterine, colorectal, and prostate), they are still relatively rare. In 2019, early start colonectal cancer occurred at a rate of 5.7 per 100,000 people (up from 3.5 in 1990) and breast cancer it occurred at a rate of 13.7 per 100,000 people (up from 9.6 in 1990) worldwide.

That’s why it’s crucial to ask family members about your medical history—it will affect when your doctor will recommend you have your first mammogram or colonoscopy and whether you may need further genetic testing. About a quarter of patients with early-onset colorectal cancer, for example, have a family history that would have warranted screening before age 45, a missed opportunity to detect or even prevent such cancers early.

When my patients ask why people get cancer, I often tell them to think of a tower of blocks. Let’s say it takes 100 blocks for a person to get cancer. Genetics, environment and lifestyle habits can add blocks to the tower.

Some of us will have genetic mutations that we inherited from our parents or will have been exposed to things in the womb that add blocks to that tower before we can crawl. Some of us will grow up in environments where we are exposed to contaminants in the air, soil or water; live in areas where ultra-processed foods are abundant and what our families can afford; or becoming infected with viruses that encourage cancer formation, none of which are factors about which we have made a conscious decision.

And then our age and many other exposures and risk factors (many of which scientists have not yet discovered, but include alcohol consumption, UV exposure, smoking and obesity) add more blocks to that tower. .

Behind the scenes, our immune system constantly fights to break down blockages, with varying success rates. No two people will acquire exactly the same 100-block constellation in the same period of time, and many will live their entire lives without reaching 100 blocks.

The factors that determine when and how a person’s tower tips toward cancer are unique, not always known, and too often beyond individual control. That’s why some people who smoke never get cancer and others who are in optimal physical condition still get it.

“One of the biggest challenges in analyzing the causes of early-onset cancers is that there is no single explanation,” he said. Bilal Siddiqui, assistant professor and medical oncologist at The University of Texas MD Anderson Cancer Center. “There are multiple environmental factors and we still don’t fully understand them all.”

Why doesn’t the immune system fight cancer?

Cancers appear in all of us every day, but fortunately, our immune system usually detects and eliminates them.

Several important factors that help cancer evade our immune system are modulated by the environment. Smoking, alcohol and genetics are well-known risk factors. Other risk factors that were less common in previous generations may also explain the increase in young cancers.

Maternal obesity and a high birth weight are associated with an increased risk of colorectal cancer. An increase in sedentary behaviors such as prolonged television viewing and consuming sugary drinks (all of which are linked to high fasting blood sugar and obesity) have been linked to early-onset cancers. Younger age at the start of a woman’s first period, older age at first birth, and use of birth control pills increase the risk of suffering from breast cancer before menopause. And for early-onset colorectal cancer, red meat consumption seems to play a detrimental role.

It’s important to remember that almost half of all cancers are preventable, Siddiqui added.

A 2022 study published in the lancet It found that about 44 percent of cancer deaths involved a modifiable risk factor, such as tobacco use or air pollution.

Early-life exposures that could lead to cancer are difficult to study; Imagine that today you are asked to remember how many minutes he was exposed to the sun 15 years ago. But scientists are working on a variety of approaches to overcome these obstacles, such as trawling electronic medical records for objective evidence and analyzing biological samples such as saliva and feces collected in childhood for clues.

What I want my patients to know

In addition to mitigating any known risk factors, we can do a better job of identifying cancer early.

After knowing your family history, take the screening test recommended by your doctor. less than 20 percent of people ages 45 to 49 are up to date with colorectal cancer screening, and only about 66 percent of women ages 40 and older were up to date with breast cancer screening.