Chemotherapy has been around for decades and it is still one of the most commonly used cancer treatments today. In the UK, around 1 in 4 of all cancer cases are treated with some form of chemotherapy - either alone, or in combination with other standard treatments. But what is chemotherapy? How does it work, and how is it different to other cancer treatments? Most importantly, how is your support helping to push forward cancer chemotherapy research?
What is chemotherapy?
Chemotherapy, sometimes called chemo for short, is a type of cancer treatment that involves using very strong drugs to damage and kill cancer cells. It is one of the three standard types of cancer treatment, along with surgery and radiotherapy. It is also increasingly used in combination with newer types of treatment, such as immunotherapies.
How does chemotherapy work?
Most chemotherapy drugs work inside the cancer cell, interfering with the various molecular mechanisms that cells use to divide, grow, and survive. Cancer cells undergo changes that give them the ability to divide and multiply very quickly, without control. This is how tumours form, and is what makes cancer cells so dangerous. Luckily, it also makes them very vulnerable to the effects of chemotherapy drugs.
Sometimes two or more chemotherapy drugs are given together in what is called combination chemotherapy. The goal is to hit cancer cells in as many different ways as possible, to make it more difficult for cancer cells to adapt and survive after treatment.
Does chemotherapy cure cancer?
In some cases chemotherapy can completely get rid of, or cure, a cancer. In other cases it shrinks the tumour or reduces the chances of cancer coming back.
Chemotherapy can sometimes be used in combination with other cancer treatments to help cure a patient, for example to reduce the size of a cancer before surgery.
Is chemotherapy effective for all types of cancer?
Chemotherapy can be used to treat many types of cancer. It does not always work on every cancer type or on every patient, because cancer is different in everyone. Research is helping us to understand why chemotherapy sometimes doesn’t work or why cancers can sometimes become resistant to it.
What is the difference between chemotherapy and other cancer treatments?
Chemotherapy is an umbrella term for cancer therapies that works by targeting rapidly dividing cells and destroying them. The drugs in chemotherapy can reach cancer cells anywhere in the body by travelling through our blood. This is different to surgery or radiotherapy which act locally where the cancer is found.
When is chemotherapy used in cancer?
Everyone’s cancer treatment plan is different, depending on the type of cancer and the stage and grade of it. Chemotherapy can be used at different stages of cancer treatment:
Induction therapy. When chemotherapy is used as the primary treatment for cancer. The aim is to reduce the size of the tumour or even completely cure the cancer.
Adjuvant therapy. When chemotherapy is given in addition to another main treatment, like surgery or radiotherapy. The aim is to destroy any cancer cells that have escaped initial treatment, and reduce the risk of the cancer returning.
Preoperative or neoadjuvant therapy. When cancer is given before the main cancer treatment, which is usually surgery. The aim is to reduce the size of the tumour before the operation, to improve the outcomes of the surgery.
What are the main types of chemotherapy drug and how do they work?
Alkylating agents. These work by 'clogging up' DNA molecules and stopping them from working properly. Fully functioning DNA is needed to keep the cell alive, growing, and dividing. By binding to DNA, alkylating agents disrupt the cell's ability to survive and thrive.
Platinum drugs. These work in a similar way to alkylating agents.
Antimetabolite chemotherapy drugs. These drugs have a similar structure and shape to the smaller molecules which make up DNA and other types of genetic molecules inside our cells. This can cause problems for the cell when it is trying to make new copies of DNA, as without new DNA the cell cannot divide.
Topoisomerase inhibitors. These drugs stop important cell molecules called topoisomerase enzymes from cutting and resealing long strands of DNA. This is particularly important when the cell is dividing, and new DNA needs to be made. Blocking these enzymes from working makes it harder for the cell to survive, especially when it is trying to divide.
Microtubule interacting agents. These drugs disrupt molecules called microtubules which are part of our cell structure. Cells use microtubules to transport molecules, and to keep their shape. Microtubules are particularly important when cells are dividing.
How is chemotherapy administered?
Many chemotherapy treatments are liquid drugs that are delivered by injection into the blood. It can sometimes take a several hours to infuse the chemotherapy drug into the body. Some chemotherapies are given by other routes, such as by mouth, or directly into the area to be treated.
It is usually administered as a course of several ‘cycles' made up of periods of treatment with periods of rest in between. The rest periods give healthy cells in your body time to recover - cancer cells tend to be less efficient at repairing themselves, and so will not be as fully recovered before the next cycle of treatment. Giving chemotherapy treatment over several rounds can also help to catch as many cancer cells as possible when they are dividing.
Doctors and scientists want to find better ways to administer chemotherapy, and research supported by our Curestarters is already helping to uncover new answers. Recent research suggests that a combination of chemotherapy and immunotherapy could be an effective treatment for some types of cancer.
What about the side-effects of chemotherapy?
Chemotherapy drugs will target any cells that are growing and dividing rapidly, and unfortunately, this can include healthy cells too.
Side-effects are often caused by inadvertent damage by chemotherapy drugs to healthy cells. For example, hair loss and nausea are linked to damage of the quickly dividing cells located in our hair roots and lining our gut.
Chemotherapy can also affect our bone marrow cells, which are responsible for producing other cells that make up our blood, including red and white blood cells. Chemotherapy-induced damage of these and other cells can increase the risk of side-effects such as infections, bruising or bleeding, and anaemia.
General tiredness and fatigue is also very common for people having chemotherapy (and other cancer treatments). It can be caused by a combination of reasons, including direct effects of treatment on the body, side-effects such as anaemia, and also the cancer itself.
Chemotherapy treatment must always involve finding a balance between effectively targeting cancer cells and minimizing damage to healthy cells. Currently, Curestarter Dr Joaquín Arribas and his team in Spain are seeking kinder treatments with fewer side effects.
Your chemotherapy FAQs:
What is chemotherapy in simple terms?
Chemotherapy is a common cancer treatment that uses very strong drugs to destroy cancer cells.
How does chemotherapy kill cancer cells?
Cancer cells divide uncontrollably which is how tumours grow. Chemotherapy works by finding these quickly dividing cells and stopping them from replicating.
Different chemotherapy drugs work in slightly different ways to interrupt cell division or destroying cells while they are dividing.
Can chemotherapy be used with other treatments?
Yes, chemotherapy is often used in combination with other treatments. Sometimes chemotherapy can be used before surgery, to reduce the size of the tumour and make it easier to operate. Or in some cases it can be used after other treatments to help stop the cancer coming back.
How is research improving chemotherapy?
Chemotherapy does not work on all cancers or on all patients. Thanks to international cancer research, we are finding ways to improve chemotherapy so that it can help more people.
Curestarter researcher Dr Renato Basto is exploring how changes in certain cell components influence the progression of ovarian cancer and its response to chemotherapy. Her team in France hope to find ways to make chemotherapy work better for ovarian cancer.
Why doesn't chemotherapy work for everyone?
Some types of cancer do not respond as well to chemotherapy or can become resistant to treatment over time. One reason for this is that molecular or genetic changes in cancer cells can give the cancer special tools to avoid the effects of chemotherapy.
Dr Di Giorgio in Italy is hoping to find a way to reprogramme bowel cancer cells so that they return to being sensitive to chemotherapy. The longer that chemotherapy keeps working for a patient, then the more effective that treatment is likely to be, so this vital research will hopefully help us reach a day where no life is cut short by cancer.
How is your support improving chemotherapy?
Thanks to our Curestarters, Professor Lorenza Penengo in Switzerland is working on finding out why some cancers treated with PARP inhibitor targeted therapies go on to develop resistance to chemotherapies.
Dr Vincenzo Giambra and his team in Italy have been finding out how a critical gene in cancer stem cells may help the blood cancer leukaemia develop resistance to chemotherapy.
And Dr Andrew Beekman and his team at the University of East Anglia are aiming to find new ways to stop cancer cells from developing resistance to chemotherapy drugs, and ultimately help chemotherapy cure more people.
Our scientists cannot carry out more crucial work like this without the support of people like you, who believe research will lead to kinder, more effective treatments and a day when no life is cut short by cancer.
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