A wide range of drugs is used to achieve these goals.
The effectiveness depends to some extent on the stage of the cancer being treated.
Adverse effects can be severe, and patients may need to discuss with their physician what to expect. The benefits of chemotherapy usually outweigh the risk of adverse effects.
Here are some key points about chemotherapy. More detail is in the main article.
- Chemotherapy is used in the treatment of cancer.
- It can prevent disease progress or bring about remission by killing the cells as they divide.
- There may be serious adverse effects, and patients should discuss these with their physician.
- Depending on the individual and the stage of the cancer, chemotherapy can bring eliminate cancer cells or bring about long-term remission of symptoms.
What is chemotherapy?
Chemotherapy is the treatment of cancer through the application of cancer-destroying drugs.
As part of the body's natural process, cells are constantly replaced through a process of dividing and growing.
When cancer occurs, cells reproduce in an uncontrolled manner.
More and more cells are produced, and they start to occupy an increasing amount of space until they occupy the space previously inhabited by useful cells.
Chemotherapy drugs interfere with a cancer cell's ability to divide and reproduce.
A single drug or a combination of drugs is used.
These can be delivered either directly into the bloodstream, to attack cancer cells throughout the body, or they can be targeted to specific cancer sites.
What does chemotherapy do?
Chemotherapy drugs can:
- impair mitosis, or prevent cell division, as in the case of cytotoxic drugs
- target the cancer cells' food source, which consists of the enzymes and hormones they need to grow
- trigger the suicide of cancer cells, known medically as apoptosis
- stop the growth of new blood vessels that supply a tumor in order to starve it
The effectiveness of stopping blood flow and oxygen to the tumor has been questioned in recent years.
Instead of starving the cells, studies have suggested that stopping the blood flow may enhance the cells' ability to resist treatment and cause metastasis.
Further investigations have led scientists to suggests that the same principle may still be useful.
They say it could be effective in preventing the cancer cells from resisting treatment by targeting the proteins that are deployed by the cancer to increase resistance and drive metastasis.
What to expect
Chemotherapy is an invasive treatment that can have severe adverse effects. This is because the drugs often target not only cancerous cells but also healthy cells.
The adverse effects can be worrying, but given early, chemotherapy can in some cases achieve a complete cure, making the side effects bearable for many patients.
It is important that patients know what to expect before starting treatment.
How long does it last?
For best results, the patient will need regular chemotherapy over a period that will be specified by the oncologist, or cancer specialist.
A plan will be drawn up that specifies when treatment sessions will occur and for how long.
A course of treatment can range from a single dose on one day to a few weeks, depending on the type and stage of the cancer.
Patients who need more than one course of treatment will have a rest period to allow their body to recover.
Treatment could occur on one day, followed by a week's rest, then another one-day treatment followed by a three-week rest period, and so on. This may be repeated many times.
A psychologist or counselor may be available to help the patient deal with the mental and emotional ordeal of chemotherapy.
Blood tests before and during chemotherapy
Blood tests are needed to assess the patient's health and to ensure that they will be able to cope with possible side effects.
For example, if a blood test detects liver problems, further treatment may be unsuitable unless the liver recovers.
Chemotherapy chemicals and other drugs are metabolized, or broken down, in the liver. If the liver is overwhelmed, this could have a range of secondary effects.
If blood testing before treatment shows a low count of red or white cells or platelets in the blood, treatment may need to be delayed.
Regular blood tests will continue during the treatment period to ensure that blood and liver function are maintained as far as possible, and to monitor the effectiveness of the treatment.
How is the dose given?
Depending on the type of cancer, the patient may take chemotherapy orally, or intravenously, injected into the vein or elsewhere.
Orally: If the patient's health allows, tablets can sometimes be taken at home. However, the patient will have to make regular hospital visits to check their health and response to treatment. The drug may also be in capsule or liquid form.
The dose must be taken exactly when specified. If the patient forgets to take one at a specific time, they should call the medical team immediately.
Intravenous chemotherapy: This may be injected directly into a vein with a needle or delivered through an intravenous infusion.
The drugs can also be given:
- as an injection into a muscle in the arm, thigh, or elsewhere
- intrathecally, injected into the space between layers of tissue that cover the brain and spinal cord
- as an intraperitoneal (IP) injection, delivered directly into the part of the body where the intestines, stomach, and liver are located
- intra-arterially (IA), injected into the artery that leads to the cancer
The drug may be given through a drip or pushed through a pump, to ensure a constant rate of delivery.
If the patient needs continuous infusion, protracted venous infusion, or ambulant infusion, they may have to wear the pump for several weeks or months. They can walk about while receiving the medication.
Devices used to deliver the solution include a catheter, a central line, and a portacath.
A portacath is an implantable port, a thin, soft, flexible plastic tube that goes into a vein. It has a port, or opening, just under the skin of the chest or arm. The port has a thin rubber disc which special needles can pass medicines into, or take blood from.
Sometimes, it is applied topically, as a cream or ointment for rubbing into the skin.
Chemotherapy often involves severe adverse effects, but recent scientific advances mean that many of these are far more manageable than in the past.
Depending on the type and extent of the treatment and other individual factors, adverse effects can range from mild to severe. Some people will have no adverse effects.
The impact of treatment on a person's daily life will depend on the extent of the symptoms.
Here are some of the adverse effects that may occur.
1: Nausea and vomiting
Nausea and vomiting affect over 70 percent of patients. Anti-emetic drugs may help. These should be taken even when symptoms have gone, to prevent them from returning.
2: Alopecia, or hair loss
Chemotherapy can lead to hair loss.
Hair may start to fall out or become thin or brittle a few weeks after treatment begins with some types of chemotherapy. It can affect any part of the body.
Hair loss has no physical health consequences, but it may cause distress. A doctor may put the patient in touch with a counselor or offer advice about obtaining a wig or other suitable covering.
Using a cold cap can keep the scalp cool while a dose is being administered, and this may prevent or reduce hair loss.
Patients who need the medication to reach their scalp, however, cannot use a cold cap. This includes patients with leukemia.
Hair normally grows back soon after treatment is finished.
Nails, too, can become flaky and brittle.
The skin may become dry and sore and oversensitive to sunlight.
Patients should stay out of the sun during peak times, use sun blocks, and wear clothes that provide maximum protection.
Fatigue is a common side effect. It may be present most of the time or only after certain activities. Patients should get plenty of rest and avoid tasks that are overtiring.
Severe tiredness should be reported to the doctor, as a significant drop in red blood cells could be leading to anemia.
4: Hearing impairment
5: Low white blood cell count and susceptibility to infections
When receiving chemotherapy, the immune system will be weakened because the white blood cell count will go down.
This is known as neutropenia. White blood cells form part of our immune system, and they fight infection. This can make patients more susceptible to infections.
Antibiotics may help reduce the risk of developing infections. Patients and their carers should also be careful to follow regular precautions.
- Personal hygiene: Regular hand washing with warm water and soap, bathing or showering at least once a day, changing clothing, bedclothes, and bathroom towels regularly.
- Preparing food: Follow food hygiene practices, including keeping meat and vegetable separate, thoroughly cooking animal produce, washing all vegetables and keeping surfaces, cutlery, and crockery clean.
- Infected people: Stay away from anyone with signs of illness or infection.
- Skin wounds: carefully dress any cuts or grazes and cover them with a sterile dressing, to prevent bacteria from entering the skin.
Chemotherapy patients who develop an infection need immediate treatment. This may mean being hospitalized and receiving intravenous antibiotics.
6: Low blood platelet count and bleeding problems
Also known as thrombocytopenia, this can lead to blood clotting problems.
Platelets are a type of blood cell that helps the blood to coagulate, or clot. A low platelet count can lead to bruises or bleeds, for example, nosebleeds and bleeding gums. The blood flow from a minor cut may be hard to stop.
If the platelet count falls too low, the person will need a blood transfusion.
To reduce the risk of bleeding, patients should:
- Use an electric razor, or avoid shaving
- Use a soft toothbrush
- Take care when using sharp objects, such as kitchen utensils or gardening tools.
Gloves can help prevent injuries when gardening.
7: Low red blood-cell count and anemia
Red blood cells carry oxygen to all the tissues in the body. A low level of red blood cells will lead to anemia. Symptoms include tiredness, shortness of breath, and heart palpitations.
A person with severe anemia may need an urgent blood transfusion.
Erythropoietin (EPO) is a drug that makes the body produce more red blood cells.
Good food sources of iron include dark green leafy vegetables, beans, meat, nuts, prunes, raisins, and apricots.
Mucositis, or inflammation of the mucous membrane, can affect any part of the digestive system, including the mouth, esophagus, stomach, intestines, the rectum, and the anus.
Oral mucositis can lead to symptoms in their mouth, often starting 7 to 10 days after treatment begins. There may be pain as if the mouth has been burned.
Ulcers can appear on the lining of the mouth, the tongue, and around the lips. Eat, drink, and talking can be painful. If bleeding occurs, there is a risk of infection.
The severity of symptoms is linked to the strength of the chemotherapy dose.
Caphosol is often prescribed for mucositis. Newer drugs can now reduce the risk of mucositis.
Symptoms disappear a few weeks after finishing treatment.
9: Loss of appetite
Either chemotherapy or the cancer itself can affect the body's metabolism, leading to a loss of appetite and weight loss until the cancer goes into remission or until treatment is finished.
Severity depends on the type of cancer and chemotherapy treatment.
Taking smaller, more frequent meals may help to keep up a supply of nourishment. Drinking liquids through a straw can help maintain fluid intake.
Patients who are unable to consume food or liquid may need to be hospitalized and fed through a nasogastric tube, which goes directly to the stomach through the nose.
10: Pregnancy and fertility
Many patients temporarily lose interest in sex during chemotherapy. Libido usually returns after treatment is completed.
Depending on the type of medication administered, chemotherapy may also reduce fertility in men and women. Fertility often, but not always, returns after treatment is over.
Patients who may wish to have children in the future may consider freezing sperm or embryos for later use.
Many chemotherapy drugs may cause congenital disabilities, so it is important to avoid becoming pregnant during treatment.
A barrier method of birth control should be used during treatment and for at least a year after. Oral birth control methods may interfere with chemotherapy.
If a woman is pregnant or becomes pregnant at the time of treatment, it is essential to tell the doctor at once.
11: Bowel problems
12: Cognitive and mental health problems
Up to 75 percent of patients report problems with attention, thinking, and short-term memory during chemotherapy. For up to 35 percent, this may persist for months or years after treatment.
It can also affect the ability to reason, to organize, and to multitask.
Mood swings and depression can also develop, whether related to the treatment itself or fears for the future.
There are different types of chemotherapy drug and different ways of receiving them.
Four major categories are:
Alkylating agents, which work directly on the DNA and kill the cells at different stages of the cell life cycle. Examples include chlorambucil, cyclophosphamide, thiotepa, and busulfan.
Antimetabolites, which mimic proteins that the cells need to survive. When the cells consume them, they offer no benefit, and the cells starve. Examples include purine antagonists, pyrimidine antagonists, and folate antagonists.
Plant alkaloids, which block the ability of the cells to grow and divide. Examples include actinomycin D, doxorubicin, and mitomycin.
Antitumor antibiotics, which bind with DNA and stop RNA from synthesizing, so that the cells cannot reproduce. These are different from the antibiotics we use for an infection. Examples include doxorubicin, mitoxantrone, and bleomycin.
The physician will recommend a suitable option, depending on what type of cancer a person has, how advanced it is, whether they have had chemotherapy before, and whether they have any other health issues, such as diabetes.
Chemotherapy can be effective in the treatment of cancer, sometimes leading to full remission in spite of its adverse effects.
Effectiveness depends on individual factors.
- the location, type, and stage of the cancer
- the patient's age, overall health, and existing medical conditions
Chemotherapy alone can, in some cases, achieve complete remission, where the patient is cured and the cancer does not return.
Sometimes, chemotherapy is combined with other treatments, such as radiation therapy or surgery, for more effective results. Neo-adjuvant therapy can be used to shrink a tumor before surgery.
Following surgery or remission, chemotherapy is used to remove any remaining cancer cells. Known as adjuvant therapy, this can delay or prevent the return of a cancer.
If a cancer is in the advanced stages, chemotherapy may slow disease progression and reduce symptoms, even when a cure is unlikely. This is palliative chemotherapy.
During and after chemotherapy, the patient will undergo blood tests and other examinations to assess the progress of the treatment.
Side effects of chemotherapy drugs tend to go away when the treatment has finished.
The earlier a cancer is treated, the more likely it is to go into remission with treatment.
Some people can work during chemotherapy, but they may need to adjust their schedule. Many employers are obliged by law to help a person do this.
Getting support during treatment
Talking to a doctor or counselor or joining a local or online support group may help.
It is important to keep in close contact with a doctor during any cancer treatment, as they can help deal with adverse effects. Patients should not make sudden changes to their lifestyle without first consulting their physician.
Chemotherapy can be expensive. It is important to talk to the doctor to find out what your options are, and to discuss with your health insurance provider which services are covered.
Some people will be able to work during chemotherapy, but others will need sick leave. Some employers are legally obliged to adapt the work schedule for patients undergoing this type of treatment.