CHEMOTHERAPY: What is chemotherapy?

By | 28/08/2018

Chemotherapy is used treatment for cancer. The term chemotherapy refers to the drugs and procedures that prevent cancer cells from dividing and growing. It does this by killing the dividing cells

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

Fast facts on chemotherapy:

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 progression 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 cancer, chemotherapy can bring eliminate cancer cells or bring about long-term remission of symptoms.

What is chemotherapy?

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 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 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 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 a 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.

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