What is chemotherapy and how does it work?

Chemotherapy is one of the most-used cancer treatments. It uses chemicals that stops the growth of cancer cells in the body. Depending on the type of severity of the cancer, chemotherapy can stop the multiplication of cancer cells, it can shrink the tumour, and also help manage the symptoms of the disease. This can help the patients enjoy a better quality of life. Unfortunately, chemotherapy comes with a wide set of side effects that need to be dealt with, as you go along the treatment. What is of paramount importance is for you to be absolutely healthy when you start the therapy.

What is chemotherapy?

Chemotherapy is an effective type of systemic treatment that uses drugs to eliminate cancer cells. “The drugs are created to target cancerous cells that multiply at an abnormal rate. Chemotherapy may be intended to completely kill or control this abnormal multiplication of cells,” explains oncologist Dr Muzammil Shaikh. The goal of chemotherapy is to inhibit cell proliferation and tumour multiplication, states this study, published by the US National Institutes of Health. Patients undergoing chemotherapy also experience side effects, such as low blood counts, nausea, and hair loss. This is the reaction of normal cells in the body, such as those in the bone marrow, where blood cells are produced, the digestive tract, and hair follicles, to the drugs and often subside upon treatment completion.

What is the purpose of chemotherapy?

The main aim of chemotherapy is to stop the cancer cells from reproducing, and prevent them from spreading in the body, states UK’s NHS. The purpose or goal of chemotherapy depends on the cancer type, stage and overall condition of the patients. “In some cases, chemotherapy may be used to eliminate cancer cells and cure cancer. In others, chemotherapy is used as an adjuvant therapy to surgery to shrink tumour size to make it operable and avoid it’s spread to surrounding tissues,” explains Dr Shaikh.

However, in advanced cases, it helps to control the tumour and provide palliation, in such cases the treatment relieves the aggravating symptoms of the disease, thereby improving the patient’s quality of life.

What are the different types of chemotherapy?

There are many types of chemotherapies that are opted for based on the condition of the patient, and the type of cancer.

1. Alkylating Agents

These drugs interfere with the DNA inside cells, preventing them from multiplying. DNA is the genetic material in cells that guides their growth and function. “By damaging the DNA, alkylating agents stop cancer cells from replicating. However, because they affect all rapidly dividing cells, they can also harm healthy cells,” explains Dr Shaikh. A study, published in Pharmacology, Toxicology and Pharmaceutical Science, states that alkylating agents are most widely used anticancer drugs.

2. Antimetabolites

These drugs mimic the building blocks of DNA and RNA, the molecules that carry genetic information in cells. “When cancer cells try to use these false building blocks to grow and divide, the process is disrupted, and the cancer cells die,” explains Dr Shaikh. A study, published in Medicine and Dentistry, states that these are drugs that disrupt cancer cell nucleic acid synthesis, a process of creating new nucleic acids, such as DNA and RNA, within a cell.

3. Antitumor Antibiotics

Despite the name, these are not the antibiotics used to treat infections. The National Cancer Institute states that these are anticancer drugs that are used to block cell growth. They interfere with DNA, the genetic material in cells. “They are drugs that bind to DNA in cancer cells, preventing the cells from replicating and eventually leading to cell death. Examples include doxorubicin and bleomycin,” says Dr Shaikh.

4. Topoisomerase Inhibitors

These drugs block the action of enzymes called topoisomerases, which help manage the structure of DNA during cell division. “By inhibiting these enzymes, topoisomerase inhibitors prevent cancer cells from dividing and growing,” says Dr Shaikh. A study, published in International Journal of Molecular Sciences, topoisomerase inhibitors can also increase therapeutic efficacy of the treatments, and decrease the chance of resistance or side effects.

5. Mitotic Inhibitors

These drugs block mitosis, the process that cells use to divide and replicate. “By stopping this process, mitotic inhibitors prevent cancer cells from multiplying,” says Dr Shaikh. This can be especially effective against cancers that grow rapidly. This can prevent mitosis, which leads to prolonged mitotic arrest and cell death, states this study, published in Neuroscience.

6. Corticosteroids

These are steroid drugs that help reduce inflammation and suppress the immune system. “In cancer treatment, corticosteroids are often used to manage side effects of chemotherapy, such as nausea and allergic reactions,” says Dr Shaikh.

How is chemotherapy given?

The most common way of administering chemotherapy is through an intravenous (IV) infusion, in which the drugs are injected directly into a vein through a needle or catheter. “In some cases, depending on the type of cancer, chemotherapy can also be advised orally, in the form of pills or capsules, injected into a muscle or under the skin, or applied topically. Chemotherapy can also be delivered directly into a specific part of the body, such as the bladder or abdominal cavity,” says Dr Shaikh.

How does chemotherapy work?

Chemotherapy targets cells that rapidly multiply. The most common trait of cancer cells is to divide, and chemotherapy stops that. “Most chemotherapy drugs interfere with the process of cell division, either by damaging the DNA or by preventing the cell from making new DNA or dividing properly,” says Dr Shaikh. However, while cancer cells are the main target, chemotherapy can also affect normal cells that divide quickly, such as those in the bone marrow, digestive system, and hair follicles. This is why side effects such as low blood counts, nausea, and hair loss are common. Check out how you can prevent chemotherapy side effects.

What to do before chemotherapy?

Prior to the treatment, the medical oncologists checks to see if the patient is fit to undergo the treatment by a general health assessment. “These include routine blood work to ensure all internal organs are functioning optimally and can support the strain caused by the treatment,” says Dr Shaikh. Besides this, doctors also enquire about patient’s medical history, existing medications and potential allergies. After clinical screening, a team of trained counsellors also connects with the patient and caregiver to offer the necessary psychological and emotional support.

What to take care of while getting chemotherapy done?

It’s of paramount importance to be completely healthy, both physically and psychologically, in order to complete the prescribed dosage of chemotherapy, as well as manage its side-effects. “Patients should stay hydrated, eat nutritious cuisines and foods, and take ample rest. As patient’s immune system is also compromised during this period, its ideal to avoid crowded spaces and meeting new or ill individuals,” explains Dr Shaikh. So, be aware of the expected side effects to be able to manage them effectively. Follow the doctors advise on regular blood tests, etc, to monitor your personal health and fitness.

What happens after chemotherapy?

The body requires adequate recovery period after chemotherapy. “Some patients may experience temporary and long-lasting side effects, from vomiting sensation to chronic fatigue. Doctors may prescribe tests and follow up with patients to review their development during the chemotherapy sessions,” says Dr Shaikh. Some patients also require medication and active clinical care to manage the long-term side effects and recover. It is important to eat well and stay healthy after chemotherapy. Check out the tweaks to make in a chemotherapy diet, in order to stay healthy.

What are the risks and precautions of chemotherapy?

Chemotherapy comes with several risks and potential side effects, including:

• Infections: Since chemotherapy weakens the immune system, patients are more prone to infections.
• Anaemia: Chemotherapy can reduce the number of red blood cells, causing fatigue and weakness.
• Nausea and Vomiting: Common side effects that can usually be managed with medications.
• Hair Loss: Due to the effect of chemotherapy on rapidly dividing cells in hair follicles.
• Organ Damage: Some chemotherapy drugs may affect organs like the heart, liver, or kidneys, so regular monitoring is necessary.

When to call a doctor?

Patients should contact their doctor if they experience any of the following symptoms:

• High fever, chills, or signs of infection, such as persistent coughing or sore throat.
•  Severe or uncontrolled side effects, such as vomiting, diarrhoea, or severe fatigue.
• Unexplained shortness of breath, chest pain, or sudden swelling.
• Any unusual or concerning symptoms, such as confusion or intense pain.