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Cancer: Frequently Asked Questions

What is cancer?

Woman talking to healthcare provider.

Cancer is when cells in the body change and grow out of control. Your body is made up of tiny building blocks called cells. Normal cells grow when your body needs them, and die when your body does not need them any longer. Cancer is made up of abnormal cells that grow even though your body doesn’t need them. In most types of cancer, the abnormal cells grow to form a lump or mass called a tumor.

What causes cancer?

Two types of factors contribute to the cause of cancer. One is a tendency or predisposition to develop cancer. The other is exposure to the triggers that start it off. Examples are cigarettes, environmental toxins, sun exposure, or liver damage.

Why do some people get cancer and not others?

In a few cancers such as retinoblastoma and in a small portion of the more common cancers such as a small proportion of breast and ovarian cancers there seems to be an inherited factor that researchers can partly identify. In most cancers, doctors assume that a person’s cells have a low threshold for becoming malignant. So that person will develop a cancer with relatively less prompting by a trigger such as cigarettes or the sun than another person whose cells have a higher threshold and who may be able to tolerate more exposure to a trigger without developing a cancer.

Is there an epidemic of cancer?

Cancer is common, but it's not really an epidemic. An epidemic means a very rapid increase in the amount of the disease, and in most cancers there is no real change. In some cancers such as stomach there has been a decrease, and in some cancers such as breast there has been a small, steady increase. This increase may be partly because of better diagnosis. There is an epidemic of discussion and awareness (thank goodness), so that at last people are talking about cancer. Until recently it had been a taboo subject.

Do we get cancer from what we eat?

Yes and no! The high-fat, low-fiber diet common in developed countries may play a role in about a third of all cancers, but doctors don't know this for certain yet. There are no toxins or chemicals in modern foods that are proved to cause cancer. In fact, the opposite is true. For example, the fact that cancer of the stomach is becoming less common may be because of the way foods are preserved.

Are chemicals and pollutants causing cancer?

In a very small portion of special cases only. In certain jobs, prolonged exposure to a few chemicals may cause certain rare kinds of cancers. Nowadays almost all of these substances have been identified and are regulated.

Does cigarette smoke really cause cancer?

Yes. Cigarettes cause the vast majority of cancers of the lung. They are a major factor in cancers of the bladder, pancreas, mouth, larynx, esophagus, and kidney.

Can cancer be prevented?

Doctors think a lot of it can. Established preventive methods including not smoking, preventing sun damage, practicing safe sexual behavior, eating a high-fiber, low-fat diet, and having regular Pap tests would reduce the incidence of cancer. It's important to note that many people who develop cancer don't have any known risk factors. But more could probably be prevented if more information was known, so research is very active in this field.

Why does the diagnosis seem to be so delayed in so many cases?

Cancer cells can multiply to produce literally billions of cells before a tumor becomes big enough to detect. That is why prevention and some methods of screening are so important.

Why isn’t there a simple, universal test for cancer?

Because cancer cells are very similar to normal cells, and a cancer begins with a very small number of cells. In a small number of cancers, certain tests can detect early changes. The best example is cancer of the cervix (the Pap test).

Also, cancer is not one disease but a category of diseases.  For example, breast cancer is much different from lung cancer, so tests to detect or diagnose it are different.

Why do people with the same cancer get different treatment and have different problems?

A lot depends on the stage of the disease and on the particular person. For instance, in breast cancer with involved lymph nodes, if you are postmenopausal, the best treatment may be a hormone tablet. If you are premenopausal, it may be chemotherapy.

Does conventional treatment work?

In many cases, yes. Surgery is an often successful conventional treatment, as are radiotherapy (after or instead of surgery) and chemotherapy. In addition, conventional treatment can produce remissions in a proportion of cases when cure is not possible. So in some cases it works, and in other cases it does not. Your doctor will be able to explain whether the chance of it working in your own case is high, low, or in-between. That is why the discussions you have with your doctor about your particular case are so important.

Why is the treatment so awful?

Many treatments are very well-tolerated, but treatment is often so awful mostly because cancer cells are only slightly different from normal cells. In this respect, cancers are totally different from, say, bacterial infections such as pneumonia or tuberculosis. Because bacteria are completely different from your body’s cells, antibiotics can kill them and not affect you very much. But because cancer cells are very like your normal cells, in order to kill them you (usually) risk doing considerable damage to normal cells or tissues.

Can fatigue be prevented?

Fatigue can't be prevented because the exact cause of fatigue is not always known. But you can decrease the effect of fatigue, such as conserving energy. If your fatigue is related to low red blood cell count (anemia), there are ways to raise your level and relieve fatigue. See the information in the fatigue topic zone, and talk with your nurse or doctor so that he or she can help you to manage fatigue.

I am going to start radiation next week. What should I expect, and what can I do to decrease the fatigue?

Fatigue related to radiation treatments usually starts about the second or third week of treatment, and may continue for up to 3 months or longer afterward. It is important to take good care of yourself. This means eating a well-balanced diet, drinking lots of fluid, sleeping well at night, and doing exercise as tolerated, such as walking regularly. Once you start feeling fatigued, match your activity to how you feel. You should identify the activities or tasks that you have to do, and ask someone else to do the other tasks.

First, if you are driving yourself to your radiation treatments, see if someone else can drive you to your radiation treatments when you start feeling tired.

Second, try keeping a diary of how you feel, what makes you feel more energetic, what makes you feel more tired. Don't do the more tiring activities. Rate the activities using a simple scale, such as on a scale of 0 (full of energy) to 10 (absolutely exhausted, no energy).

Third, talk with your doctor or nurse about problems that arise, or if your fatigue is severe.

How does fatigue affect a person?

Fatigue affects each person differently. In addition, there are various degrees of fatigue. Some people may find that they are unable to do simple things that they used to do, such as climbing stairs without stopping or holding onto the handrail. Others may have trouble standing up in the shower, and get too tired, so a shower chair is helpful. Changes in mental processes can happen, and cause “fuzzy thinking.” It may be hard to concentrate or focus on things, such as reading or watching television. Visiting with family, cooking, or other activities that you used to enjoy before starting cancer treatment may now be too exhausting. But there are tips to help conserve your energy for the activities that are important to you.

How can I ask my family to help me?

This may be one of the hardest things to do. Most family members want to help and are just waiting to do something. Often they feel helpless, and afraid to ask if they can help. By being very specific about what you would like them to do, it will make it much easier for them to help. Sometimes, a family meeting is a good way to tell family what is going on, and to organize the tasks and activities. A family meeting may also be helpful when family members may not understand that fatigue is a real problem related to cancer and its treatment. Your doctor, nurse, or a social worker can help with this, too.

I’m taking interferon therapy, and am so tired. What can I do?

Fatigue is very common with interferon alfa treatment, as well as from cancer. Usually a full assessment is done to make sure that other treatable causes aren’t overlooked. These include:

  • Too little thyroid hormone (hypothyroidism)

  • Low red blood cell count (anemia)

  • Depression

  • Low blood sugar (hypoglycemia)

  • Too little fluid in the body (dehydration)

Things that have helped other people receiving interferon who get fatigue:

  • Distraction. This includes daydreaming, laughter, meditation, prayer, reading, soft music, soaking in the tub, watching TV or writing.

  • Saving energy. This includes keeping exertion at a minimum, getting extra sleep or taking a quick nap, relaxing, resting or sitting quietly, planning activities, and slowing down.

  • Using energy. This includes getting exercise such as swimming or walking.

  • Medical treatments. These include blood transfusions and pain control.

  • Other activities such as eating food and drinking ice water.

When should I call the nurse or doctor about my fatigue?

You should call your nurse or doctor if any of the following occur:

  • Feel dizzy

  • Lose your balance

  • Have trouble sitting, standing, or walking

  • Sleep all the time

  • Can’t sleep at night

  • Suddenly feel much more fatigued

  • Hurt yourself

  • Need help talking with your family about your feelings or needs

  • Any new problem that you need help with

Is fatigue a real symptom?

Yes, fatigue is a real symptom. Fatigue can lead to a decrease in quality of life. Factors such as treatment, low red blood cell count (anemia), stress, difficulty sleeping, and poor nutrition can all add to fatigue. Still, since no one else can see your fatigue, it's common to question yourself about it. Don't. Fatigue is often a real part of cancer and its treatment. 

How can I get the best from my doctor?

Doctor-patient relationships are similar in some respects to marriages:. Some are good and some are bad, and a lot depends on the people involved. The key to getting the best from your medical team is to present your problems as clearly and accurately as you can and clarify exactly what it is you want to know and what you need.

Why are people so frightened of cancer?

Probably because so many of the other major threats to health have faded somewhat. Until the 1940s people used to be afraid of syphilis and tuberculosis. Before that it was cholera and smallpox. Currently, cancer and infectious diseases are occupying the roles of humankind’s bogeyman diseases. Cancer has not changed very much, but people's perception of it has. In fact, the prevention and treatment of cancer has never been as promising as it is today. 

Can attitudes or stress cause cancer?

Not as far as researchers know. In fact, the idea that the cancer “personality” or a bad attitude contributes to the cause of cancer may be part of the ancient human habit of blaming the patient for the disease.

Can a change in diet alter the course of cancer?

Again, not as far as researchers know. Many cancer centers are currently involved in finding out whether a certain diet can alter the course of cancer in some selected early cases. But there is no evidence that diet supplements, vitamins, minerals, or special diets actually change the course of a cancer once it has developed.

With so many advances, why isn't there more progress?

Researchers have made tremendous—and increasing—progress in their understanding of cancer, but the gap between understanding and treatment (between lab and bedside) is a wide one. Because stories about cancer research are often reported in the media as if that gap were small, people tend to expect big changes in treatment. This tendency is partly responsible for the widespread feeling of disappointment with the impact of cancer research.

Will there ever be a cure for cancer?

Many cancers ARE cured. Since every cancer is different, finding a single universal cure is unlikely. This is similar to there not being a single antibiotic that cures all infections. It's quite likely that researchers will make further advances in some cancers. The biggest changes in cancer may come from prevention or from other directions, such as treatments or vaccines to prevent spread after the primary cancer has been removed. Obviously nobody knows what is going to happen, but a single, sudden breakthrough that produces a universal miracle cure is very unlikely.

Can humans ever be free of cancer?

Probably not. It's likely that humans evolved with a design that was quite satisfactory if a person lived for 3, 4, or perhaps 5 decades. The problem is that people are now quite good at dealing with the forces that, centuries ago, used to kill people off before they were 60. Now that many more of people are living into their 60s, 70s, and beyond, cancer is a flaw that appears with increasing frequency as cells do more and more multiplying and get older. It's possible that researchers can devise ways of stopping this flaw from appearing, but it is equally possible that cancer is not eradicable in the way smallpox was.

Will my hair grow back?

Yes, hair loss from chemotherapy is temporary. It will grow back, usually after therapy is finished. In some cases, hair can grow back during therapy. Usually the texture of the hair is different for the first year. Then, after a year or so, it usually goes back to how it was before you took chemotherapy. Hair loss from radiation therapy may be irreversible.

If I have a lot of side effects, does that mean the chemotherapy is working?

No. The side effects occur because the chemotherapy hurts normal cells that divide often, as well as the cancer cells. There is much that can be done to prevent or lessen the side effects that a person gets after chemotherapy.

Are the side effects of chemotherapy worse than the cancer?

Nausea and vomiting are are the worst of the side effects for many people. These often can be controlled. Fatigue is finally getting the attention it deserves, and there are many self-care tips that can help. Anemia, which can cause fatigue, can also be prevented or treated in many cases.

Does everyone with cancer get anemia?

No. Anemia is a common condition that can be caused by non-cancer (benign) conditions. Some cancers can suppress the body's ability to make blood normally. Some cancer treatments can cause anemia. Many cancer patients will never have anemia; and many people without cancer can develop anemia for other reasons.

What effect does alcohol have?

Anemia has many different types and causes. Alcohol can cause anemia by suppressing the body's ability to make blood normally. Alcohol use can also lead to conditions that increase the risk of bleeding, poor nutrition, and chronic disease that leads to anemia. If you have questions about using alcohol during cancer treatment, talk with your doctor about healthy habits related to it.

Why don’t I get anemia right after my chemotherapy?

The red blood cells in the body live for about 120 days, or 3 months. Chemotherapy doesn’t hurt the red blood cells that are already made and circulating in the blood. Chemotherapy injures the cells in the bone marrow that make the red blood cells. The chemotherapy prevents these cells from replacing the normal red blood cells when they are used up. That is why the anemia may not develop for a while after the chemotherapy starts.

How is anemia treated?

This depends on the cause of the anemia. If the anemia is caused by not enough building blocks in the body, like iron, folic acid, or vitamin B12, the treatment includes adding these back to the body. Red blood cells can then be made, and the blood values return to normal. If the cause is chemotherapy, or sometimes radiation, then red blood cell transfusions or injections of erythropoietin can be given in some cases. Erythropoietin is a natural hormone made by the kidneys that tells the bone marrow to make more red blood cells.

Should everyone get a second opinion?

Many people with cancer get a second opinion from another doctor. There are many reasons to get a second opinion, including if you are not comfortable with the treatment decision, if the type of cancer is rare, if there are different ways to treat the cancer, or if you are not able to see a cancer expert. Also, some health insurance companies require a second opinion before treatment begins. A second opinion can help you have more confidence in the cancer diagnosis, treatment plan, or treatment team.

How can someone get a second opinion?

You can get a second opinion in many ways:

  • Your primary doctor may be able to recommend a specialist, such as a surgeon, medical oncologist, or radiation oncologist. Sometimes these doctors work together at cancer centers or programs.

  • The contact information for the Cancer Information Service is 800-4-CANCER (800-422-6237). This service informs callers about treatment facilities, including cancer centers and other programs supported by the National Cancer Institute.

  • You can get names of doctors from your local medical society, a nearby hospital, a medical school, or local cancer advocacy groups, as well as from other people who have had that type of cancer.

Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Sabrina Felson MD
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 5/1/2023
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