Cancer facts for kids

Cancer is a serious disease where some cells in your body start to grow and divide without stopping. Normally, your body's cells grow and replace themselves in a controlled way. But with cancer, something goes wrong.

These changed cells, called cancer cells, can spread and invade other tissues and organs. If they only grow in one spot and don't spread, it's usually called a tumour. Tumours are often not dangerous and can be removed. However, some tumours can be serious, especially if they are in places that are hard to reach, like some brain tumors.

When cancer cells spread to other parts of the body, it's called metastasis. This happens when cancer cells travel through your blood or lymphatic system. When cancer spreads, it can make it harder for different body parts to work properly.

Cancer can affect anyone at any age. But it's more common in older people. This is because their DNA might get damaged over time. One type of cancer, testicular cancer, is actually more common in young men.

Studying cancer and finding ways to treat it is a big field called oncology. It's one of the most researched causes of death in many countries.

What Causes Cancer?

Cancer is a major health issue worldwide. About one out of every six deaths globally is linked to cancer, according to the World Health Organization.

Different types of cancer can have different causes. Some things are known to cause cancer in specific body parts. Other things can cause many types of cancer. For example, using tobacco (like smoking or chewing) can cause lung, mouth, tongue, and throat cancers.

Things that can increase your risk of getting cancer include:

• Radiation, like too much sunlight or many X-rays.
• Exposure to radiation from places like a nuclear power plant.
• Certain chemicals used in construction or factories, such as asbestos and benzene.
• Diets high in fat or low in fiber.
• Air and water pollution.
• Not eating enough fruits and vegetables.
• Obesity (being very overweight).
• Not getting enough physical activity.
• Drinking too much alcohol.
• Some viruses can also cause cancer.

It's important to remember that many people exposed to these things do not get cancer.

Types of Cancer

There are many different kinds of cancers. The most common cancers around the world are:

• breast cancer
• lung cancer
• colorectal cancer
• prostate cancer
• stomach cancer

Treating Cancer

There isn't one simple cure for cancer. The best chance for a cure is to remove or kill all the cancer cells. This means that treating cancer early often gives the best results. This is because the cancer cells might not have had time to spread widely.

Here are some common ways doctors treat cancer:

• Radiotherapy: Uses strong radiation to kill cancer cells.
• Chemotherapy: Uses powerful medicines to kill cancer cells.
• Surgery: Doctors cut out part or all of a tumour. After surgery, patients often need radiotherapy or chemotherapy to stop the cancer from growing back.
• Immunotherapy: This treatment helps your body's own immune system fight the cancer.

Why Treating Cancer Is Tricky

Treating cancer can be complicated for a few reasons:

• Many treatments that kill cancer cells can also harm healthy cells. This can cause side effects like hair loss or vomiting.
• Your immune system usually doesn't attack cancer cells. This is because cancer cells start as your own cells. So, your immune system sees them as part of your body, not as a threat.
• There are many types of cancer, and each can act differently. Even people with the same type of cancer might have different symptoms or react differently to treatments.
• Treatment needs to be carefully chosen for each type of cancer and for each patient.

Many scientists and doctors around the world are working hard to find better treatments. There has been good progress, and many cancers can now be treated successfully. Besides medical treatments, some studies also look at what people with cancer can do to help themselves. For example, some research shows that exercise can help certain patients.

History of Cancer Research

Cancer has been around for thousands of years. Many medical words we use today for cancer come from ancient Greek and Latin. For example, the word carcinoma describes a dangerous tumor made of cancer cells. The Greek word "karkinos" meant "crab," and the Romans translated it to "cancer." This is because early doctors thought tumors looked like crabs with their veins spreading out.

The word oncology, which is the study of cancer, comes from the Greek word "onkos," meaning "tumor" or "swelling."

Early Discoveries

Hippocrates, a famous ancient Greek doctor, named many kinds of tumors. He called harmless tumors oncos (swelling) and dangerous ones karkinos (crab). He added -oma (swelling) to karkinos to create carcinoma.

Ancient Greek doctors didn't open up bodies to study them. So, Hippocrates only described tumors he could see from the outside, like on the skin or breasts. They treated patients based on the humor theory, which said the body had four fluids that needed to be balanced. Treatments included blood-letting or special diets. This theory was popular until the 1800s, when cells were discovered.

The oldest known document about cancer is from Egypt around 1600 B.C. It talks about treating breast ulcers with burning tools, but also says, "There is no treatment."

In the 1020s, a doctor named Avicenna suggested cutting out all diseased tissue, even removing body parts or veins if needed. He also suggested burning the treated area.

Modern Understanding

In the 1500s and 1600s, doctors started to dissect bodies after death to find out why people died. This led to new ideas about cancer. Some thought it was caused by milk clots, others by acidic fluids, and some even thought it was contagious.

In 1775, a British surgeon named Percivall Pott discovered that scrotum cancer was common among chimney sweeps. This was one of the first times a real cause of cancer was identified.

The microscope became widely used in the 1700s. Scientists could then see that cancer spread through the lymph nodes to other parts of the body. This spread is called metastasis.

Before the 1800s, cancer surgery was very risky. Patients often died from infections because doctors didn't understand hygiene. For example, one surgeon found that most patients who had breast tumor surgery died within two years.

Advances in the 1800s

In the 1800s, surgical hygiene greatly improved with asepsis (keeping things germ-free). Doctors realized that germs caused infections. This made surgery much safer, and removing tumors became the main treatment.

The discovery that the body is made of tissues and millions of cells led to pathology, the study of diseases at the cell level.

In the 1890s, French scientists discovered radioactive decay. This led to Radiation therapy, the first cancer treatment that didn't involve surgery. This meant doctors had to work together in teams, and treatment moved from homes to hospitals. Hospitals started keeping "medical records," which helped scientists study how many patients survived different cancers or treatments.

The 1900s and Beyond

In 1926, Janet Lane-Claypon published an important paper on cancer epidemiology. This field studies how common a disease is and what patterns it follows in different groups of people. Her study compared people with breast cancer to those without, looking for differences in their lives.

Later, Richard Doll and Austin Bradford Hill continued this work, focusing on lung cancer and its link to smoking. Their "British doctors study" in 1956 was very important. With computers, scientists could collect and study huge amounts of cancer data. This helped us understand what makes people more or less likely to get different cancers.

After World War II, countries realized that cancer rates varied greatly around the world. This led to national public health organizations collecting health data from many doctors and hospitals. For example, in Japan, studying survivors of the atomic bombings of Hiroshima and Nagasaki helped doctors understand that radiation could destroy bone marrow. This was a key step in learning that leukemia (a blood cancer) can be treated with bone marrow transplants.

Since World War II, cancer treatments have continued to improve. However, there are still challenges. Some cancers still lack good treatments, especially in later stages. Also, treatments are not always the same everywhere, and they are not available to everyone around the world. Scientists continue to work together internationally to find cures and make treatments available to all.

Images for kids

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  Share of cancer deaths linked to tobacco in 2016.

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  Cancers are caused by several changes (mutations) in cells. Each change alters how the cell behaves.

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  Engraving showing a Dutch woman who had a tumor removed from her neck in 1689.

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  The University of Florida Cancer Hospital.

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  CancerTreeMammal

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  A squamous-cell carcinoma (the whitish tumor) near the bronchi in a lung.

See also

In Spanish: Cáncer para niños