Why does chemotherapy cause side effects?

Cancer cells tend to grow rapidly, and chemotherapy drugs kill rapidly growing cells. But because these drugs travel throughout the body, they can also affect normal, healthy cells that are growing quickly. The damage to healthy cells causes side effects. Side effects aren't always as severe as you might think, but it's normal to worry about this part of cancer treatment.

The normal cells most likely to be damaged by chemo are:

• Blood-forming cells in the bone marrow;
• Hair follicles;
• Cells in the mouth, digestive tract, and reproductive system;

Some chemotherapy drugs can damage cells in the heart, kidneys, bladder, lungs, and nervous system. Sometimes, you can take medications at the same time as chemo to help protect your body's normal cells. There are also treatments that help relieve side effects.

Doctors try to give chemotherapy at levels high enough to treat the cancer while limiting side effects as much as possible.

What should I know about chemotherapy side effects?

Everyone experiences chemotherapy side effects differently, and their severity varies. Your doctor can give you medications to help prevent some side effects before they occur.

Some chemotherapy drugs cause long-term side effects, such as heart or nerve damage or fertility problems. However, many people do not experience long-term problems due to chemotherapy. Ask your doctor if the chemotherapy drugs you are taking could cause long-term effects.

While side effects can be unpleasant, they must be weighed against the necessity of killing cancer cells.

Remember to ask your healthcare team about the most common side effects of your chemo, how long they might last, and how severe they might be.

How long do chemotherapy side effects last?

Many side effects go away fairly quickly, but some may take months or even years to disappear completely. These are called late side effects.

Sometimes, side effects can last a lifetime, such as when chemo causes long-term damage to the heart, lungs, kidneys, or reproductive organs. Some types of chemotherapy sometimes cause late effects, such as a second cancer that may appear years later.

Patients often get discouraged about the length of their treatment or the side effects it causes. If you feel this way, talk to your cancer care team. They may be able to change your medication or treatment program. They may also be able to suggest ways to reduce the pain and discomfort you are experiencing.

What are common chemotherapy side effects?

Here are some of the most common side effects caused by chemotherapy:

• Fatigue;
• Hair loss;
• Easy bruising and bleeding;
• Infection;
• Anemia (low red blood cell count);
• Nausea and vomiting;
• Loss of appetite;
• Constipation or diarrhea;
• Mouth, tongue, and throat problems such as sores and painful swallowing;
• Peripheral neuropathy or other nerve problems, such as numbness, tingling, and pain;
• Changes in skin and nails, such as dry skin and discoloration;
• Changes in urine and bladder and kidney problems;
• Weight loss;
• Decreased concentration;
• Mood changes;
• Decreased libido;
• Fertility problems;

Chemotherapy Drug Interactions and Side Effects

When figuring out the best way to combine chemotherapy drugs, doctors must consider interactions between chemotherapy drugs and other medications a patient is taking, including over-the-counter drugs, vitamins, and supplements. Combining multiple drugs with chemotherapy can worsen side effects and affect the effectiveness of chemo drugs. For example, many chemotherapy drugs lower your platelet count for a while. Taking aspirin or other related medications can also weaken blood platelets. This isn't a problem for healthy people with normal platelet counts, but if someone has a low platelet count because of chemotherapy, taking aspirin could put them at risk for a serious bleeding problem.

It is important to tell your doctor about all the medications you take, including over-the-counter drugs, vitamins, herbal remedies, or supplements, even if you only take them occasionally.

Your doctor can discuss with you the safety of using other medications, vitamins, and supplements during your cancer treatment.

When to call the doctor?

Don't take your physical symptoms lightly. Some side effects are short-lived and minor, but others can be signs of serious problems. Make sure you know how to reach a member of your team at all times, including after hours, weekends, and holidays.

Contact your doctor immediately if you experience any of the following symptoms during your chemotherapy treatment:

• A fever above 100.4°F (38°C);
• Unexplained bleeding or bruising;
• A rash;
• An allergic reaction, such as swelling of the mouth or throat, significant itching, difficulty swallowing;
• Severe chills;
• Pain or soreness at the chemo injection site or catheter;
• Unusual pain, including severe headaches;
• Shortness of breath or difficulty breathing;
• Prolonged diarrhea or vomiting;
• Bloody stools or blood in the urine;