What is cancer?
Cancer is not just one disease. It is a group of diseases. So far, more than 100 different types of cancer have been identified. But all forms of cancer start because of out-of-control growth of abnormal cells. Most types of cancer cells form a lump called a tumor, which may invade the tissues around it. Cells from the tumor can also break away and travel to other parts of the body. There they may continue to grow and form more tumors. This process of spreading is called metastasis. Even when cancer spreads somewhere else in the body, it is still the same kind of cancer, and is still named after the part of the body where it started. For example, if lung cancer spreads to the bones, it is still lung cancer, not bone cancer. In that case, it may be said that the person has “lung cancer with bone metastases.” Some cancers, such as cancers of the blood, do not form a tumor. Cancer of the blood is called leukemia. Not all tumors are cancer. A tumor that is not cancer is called benign. Benign tumors do not grow and spread the way cancer does. In most cases benign tumors cannot kill you. Another word that also means cancer is malignant. So, a tumor that is cancer is called a malignant tumor. Untreated malignant tumors can kill you.
What causes cancer?
Things people do. . .
Some kinds of cancer are caused by things people do. For example, smoking can cause cancers of the lungs, mouth, throat, bladder, kidneys and other organs, as well as heart disease and stroke. While not everyone who smokes gets cancer, smoking increases a person’s chance of getting the disease.
Being in the sun too much without protection can cause skin cancer. Melanoma is a very serious form of cancer that is linked to sunlight and tanning bed exposure.
Things people are exposed to. . .
Radiation can cause cancer. For example, people exposed to nuclear fallout have a higher cancer risk than those who were not exposed. Rarely, radiation treatment for one type of cancer can cause another cancer to grow many years later.
Certain chemicals have been linked to cancer, too. Being exposed to or working with them can increase a person’s risk of having cancer.
Genes that run in families. . .
Of every 20 cases of cancer, about 1 is caused by genes that are inherited from parents.
What is the bottom line?
No one knows the exact cause of most cases of cancer. We know that certain changes in our cells can cause cancer to start, but we don’t yet know exactly how it all happens. Scientists are studying this problem and learning more about the many steps it takes for cancers to form and grow. Although some of the factors in these steps may be a lot alike, the process that happens in the cells is generally different for each type of cancer.
Can injuries cause cancer?
No. It is a common myth that injuries can cause cancer. The fact is that a fall, a bruise, a broken bone, or other such injury has not been linked to cancer. Sometimes a person might visit the doctor for what is thought to be an injury and cancer is found at that time. But in cases like this, the injury did not cause the cancer; it was already there. It also sometimes happens that a person will remember an injury that happened long ago in the place cancer was found. Rarely, burn scars can be the site of cancer many years after the burn has healed. Most often, skin cancer is the type that grows in a burn scar.
Can stress cause cancer?
Researchers have done many studies to see if there is a link between personality, stress, and cancer. No scientific evidence has shown that a person’s personality or outlook can affect their cancer risk. However, there are many factors that come into play when looking at the relationship between stress and cancer. While it is known that stress affects the immune system, so do many other factors. Despite many studies, a link between psychological stress and cancer has not been proven. Looking at the studies that have been done, it seems they sometimes come to opposite conclusions.
Is cancer contagious?
In the past, people often stayed away from someone who had cancer. They were afraid they might “catch” the disease. But cancer is not like the flu or a cold. You cannot catch cancer from someone who has it. You will not get cancer by being around or touching someone with cancer. Don’t be afraid to visit someone with cancer. They need the support of their family and friends.
Can cancer be prevented?
Tobacco and alcohol. . .
Smoking and drinking alcohol cause some people to get certain types of cancer.
Many of these cancers might be prevented by not using tobacco or alcohol.
Ultraviolet (UV) rays and sunlight. . .
You can lower your chances of getting skin cancer by staying out of the sun between the hours of 10 a.m. and 4 p.m., wearing a hat, shirt, and sunglasses when you are in the sun, using sunscreen with a sun protection factor (SPF) of 15 or higher and not using tanning beds or lamps.
Diet. . .
We know that our diet (what we eat or don’t eat) is linked to some types of cancer, although the exact reasons are not yet clear. The best information we have suggests a lower cancer risk for people who eat a lot of fresh fruits and vegetables (at least 5 servings a day), choose whole grains rather than refined grains and sugars, limit red meats (beef, pork, and lamb), limit processed meats (such as bacon, lunch meats, and hot dogs), choose foods to help stay at a healthy weight and limit alcohol intake to 1 alcoholic drink a day or less for women and 2 or less for men.
Early detection. . .
To find cancer early, adults should have regular tests, called screening examinations. Talk to your doctor about which screening tests might be right for you. If cancer is found early, it can often be treated successfully.
Survival rates. . .
The survival rates are different for people with different types of cancers. Some types of cancer grow very slowly. Some respond to treatment very well. Others grow and spread faster and are harder to treat. If you know someone who has cancer, keep in mind that what happens to them could be very different from what happens to someone else with another type of cancer.
How is cancer treated?
Surgery, chemotherapy and radiation are the 3 main types of cancer treatment. A person with cancer may have any or all of these treatments. Surgery is often the first treatment option if the cancer is a tumor that can be removed from the body. Sometimes only part of the cancer can be removed. Radiation or chemotherapy might also be used to shrink the cancer before or after surgery.
Doctors use chemotherapy or “chemo” to kill cancer cells. The term chemotherapy refers to the use of drugs to kill cancer. Usually, the drugs are given intravenously or taken by mouth. Chemo drugs then travel throughout the body in the bloodstream. They can reach cancer cells that may have spread from the tumor.
Radiation therapy is treatment with high energy rays to kill or shrink cancer cells. The radiation may come from outside the body, called external radiation, or from radioactive materials placed directly in the tumor (internal or implant radiation). The procedure for getting external radiation is much like that of getting an x-ray and is painless, although some people have side effects.
Other kinds of treatment you might hear about include hormone therapy, stem cell or bone marrow transplant, and immunotherapy. Hormone therapy is sometimes used to treat certain kinds of prostate and breast cancers. Immunotherapy is treatment designed to boost the cancer patient’s own immune system to help fight the cancer.
What are the side effects of cancer treatment?
The type of treatment a person gets depends on the type and stage (extent) of the cancer, the age of the patient, and his or her medical history and general health. Each drug or treatment plan has different side effects. It is hard to predict what side effects a patient will have, even if patients get the same treatment. Some effects can be severe and others fairly mild. It is true that some people have a tough time with cancer treatment, but there are also many who manage quite well throughout treatment.
Chemo side effects can include nausea and vomiting, loss of appetite, hair loss and mouth sores. Because chemo can damage the blood-producing cells in the bone marrow, patients may have low blood cell counts. This can lead to increased risk of infection (from a shortage of white blood cells), bleeding or bruising after minor cuts or injuries (from a shortage of blood platelets), anemia (from low red blood cell counts), which can cause tiredness, shortness of breath, pale skin, and other symptoms. Because everyone’s body is different, each person will respond differently to chemo. Most of the side effects of chemo go away after treatment ends. For example, hair lost during treatment always grows back. In the meantime, most patients are able to use wigs, scarves, or hats to cover, warm, or protect their heads.
Radiation treatments are much like x-rays and do not cause any pain. The most common side effects are skin irritation and fatigue. Fatigue is a feeling of extreme tiredness and low energy. It is especially common when treatments go on for many weeks. Fatigue often does not get better with rest. People also sometimes say that their fatigue is made worse by the daily trips to the hospital to get their radiation treatments.
There are times when every cancer patient questions their commitment to the difficult journey of treatment and its side effects. Sometimes they can get discouraged by the uncertainty of treatment and wonder if it’s worth it. This is normal. It may help to remember that every year, cancer treatments get more and more effective, and doctors are always learning better ways to work with patients to control treatment side effects, too.