Why do young people get cancer even though they are healthy?

Although early onset rates are increasing for many types of cancer, including breast, uterine, colorectal, and prostate cancer, the incidence is still relatively low. 2019, early onset colorectal cancer Occurring at a rate of 5.7 per 100,000 people (up from 3.5 in 1990), breast cancer It occurs at a rate of 13.7 per 100,000 people worldwide (up from 9.6 in 1990).

This is why it's important to ask your family about their health history. This affects when your doctor may recommend you have your first mammogram or colonoscopy and whether further genetic testing is needed. For example, approximately one-quarter of patients with early-onset colorectal cancer have a family history that should have led to screening earlier than age 45, meaning missed opportunities to detect or prevent these cancers early. It will be.

When patients ask me why they get cancer, I often tell them to think of a tower of blocks. Let's say that before a person gets cancer he needs 100 blocks. Genetics, environment, and lifestyle can all add obstacles to your tower.

Some of us may have genetic mutations inherited from our parents. Or maybe some people are exposed in utero to things that add blocks to that tower before they can crawl. Some of us grow up in environments where we are exposed to pollutants in the air, soil, and water. I live in an area where ultra-processed foods are most plentiful and within our family's means. Or it's not a factor we consciously choose, such as being infected with a virus that stimulates the formation of cancer.

And our age and numerous other exposures and risk factors (many of which scientists still don't understand, such as alcohol intake, UV exposure, smoking, and obesity) all add further blocks to that tower. Add.

Behind the scenes, our immune systems are constantly scrambling to rip off blocks, with varying degrees of success. No two people can achieve exactly the same 100 block constellation in the same amount of time, and many people end up living their lives without reaching 100 blocks.

The factors that determine when and how someone's tower succumbs to cancer are unique, not always known, and too often out of the individual's control. This is why some smokers never develop cancer, while others who are in the best of health develop cancer.

“One of the biggest challenges in understanding the causes of early-onset cancer 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, all of which we don't fully understand yet.”

Why doesn't the immune system fight off cancer?

Cancer occurs in everyone every day, and fortunately, cancer is usually detected and eliminated by the immune system.

Several key factors that help cancer evade the immune system are regulated 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 high birth weight Associated with increased risk of colorectal cancer.Increased sedentary behavior such as: watching TV for a long time and consume sweet drink All of these are associated with high fasting blood sugar levels and obesity, and are thought to be involved in early carcinogenesis.Declining age at women's onset of menarche, increasing age at first birth, and use of oral contraceptives are all increasing risk Getting breast cancer before menopause. In the case of early-onset colorectal cancer, intake of red meat It appears to play a detrimental role.

Siddiqui added that it's important to remember that almost half of all cancers are preventable.

Research results published in 2022 lancet Approximately 44 percent of cancer deaths were found to be associated with modifiable risk factors such as tobacco use and air pollution.

It is difficult to study childhood exposures that can lead to cancer. Imagine being asked today to recall how many minutes you spent playing in the sun 15 years ago. But scientists are working on: different approaches Overcoming these obstacles requires scouring electronic health records for objective evidence and analyzing biological specimens such as saliva and stool collected during childhood for clues. .

What we want patients to know

In addition to reducing known risk factors, early detection of cancer can be more effective.

Once you have researched your family history, take the tests your doctor recommends. less than 20 percent Only about 1 person between the ages of 45 and 49 is up to date with colorectal cancer screening. 66 percent Among women aged 40 years and older, most women undergo breast cancer screening.