Chemotherapy types

Overview

A cell is the basic unit of the living organism. In our body, the cell divides and forms new cells. This is called cell division.  

Cancer is a disease associated with an uncontrolled growth of abnormal cells in the body. In cancer-affected areas of the human body, the mutated cells split and form new cells uncontrollably. Thus, the accumulation of cells in the affected area is inevitable.  

This forms a lump in tissues (except for blood cancer) and makes its way into cancerous tumours. Some types of cancer, for example, Leukemia, do not form tumours.  

Some treatments to treat cancer are radiation therapy, surgery and chemotherapy.

Chemotherapy is a treatment method that uses drugs to kill cancerous cells. This treatment differs based on the type of drugs given, how it is given, etc.  

How does chemotherapy work?

• Unlike normal cells, cancer cells multiply and grow at a faster rate. Chemotherapy is a treatment that obstructs the division and growth of cancerous cells. This can be done using a single drug or a combination of drugs.  
• Chemotherapy is used either as a standalone treatment or in combination with other treatments.  Usually, oncologists use it before radiation or surgery to reduce the size of the tumours. Such treatment is called Neoadjuvant chemotherapy.
• Used after surgery and/or radiation therapy to kill the remaining cancer cells. This is known as Adjuvant chemotherapy.
• It is used as a standalone treatment to treat cancers such as Leukemia and Lymphoma as the cancer cells affect the blood and lymphatic system, respectively.
• It is widely used to treat recurring cancers as radiation and surgery cannot be performed frequently.  
• It is also used to treat metastatic cancer—cancer that spreads to other body parts.  

What are the types of chemotherapy?

Chemotherapy is a treatment using chemical drugs to kill cancerous cells. Oncologists currently use more than 100 drugs for chemotherapy. These drugs are classified based on their action. They are:

• Alkylating agents
• Anti-metabolites
• Anti-tumour antibiotics
• Plant alkaloids
• Corticosteroids

Alkylating agents

Alkylating agents are one of the common types of chemotherapy drugs used for various types of cancers.

• Lung cancer
• Breast cancer
• Ovarian cancer
• Multiple myeloma

These agents work by affecting the DNA inside the cancer cells, thus preventing them from multiplying. Some common drugs that come under this category are Chlorambucil, Cyclophosphamide, Busulfan, etc.

Anti-metabolites

This category of drugs alters the DNA structures and hinders the function of enzymes in the cells. These are used to treat the following types of cancer:

• Leukemia
• Gastrointestinal cancer
• Breast cancer
• Ovarian cancer

Some common drugs that come under this category include Azacitidine, Clofarabine and Floxuridine.  

Plant alkaloids 

Plant alkaloids are the drugs that are derived from plants. These drugs generally have anti-tumour properties. This category of drugs can be divided into two sub-groups.  

• Topoisomerase inhibitors

These drugs inhibit the ability of the enzyme topoisomerase to divide and multiply. Thus, it prevents the formation of cancerous tumours. These are used to treat:

• Lung cancer
• Pancreatic cancer
• Ovarian cancer
• Leukemia
• Gastrointestinal cancer

Some topoisomerase drugs pose the risk of re-emergence of cancer in some people. Some common drugs that fall under this category are Irinotecan, Topotecan, Teniposide, etc.  

• Mitotic inhibitors

Mitotic indicators affect the enzyme of the cell that is responsible for producing certain kinds of proteins. This obstructs the cell division and growth of cancer. This type of drug is used to treat:

• Lymphoma
• Leukemia
• Breast cancer
• Lung cancer
• Myeloma

Some medications include Cabazitaxel, Docetaxel and Vinorelbine.  

Anti-tumour antibiotics 

These drugs are produced by microorganisms that disturb the growth of cancerous cells. The chemicals in these drugs diminish the replicating property of the DNA of the cancer cells, thus arresting the cell division. These drugs are highly different from the common antibiotics.  

These are used to treat the following cancers:

• Lung cancer
• Prostate cancer
• Colorectal cancer
• Ovarian cancer

The medications usually prescribed under this category include Doxorubicin, Bleomycin and Mitoxantrone.  

Corticosteroids

Corticosteroids are the kind of steroids commonly used in chemotherapy to treat cancer or suppress the side effects caused by the usage of other drugs in chemotherapy. The common side effects these steroids fight are gastric and allergic reactions.  

Are there any side effects with chemotherapy?

Although chemotherapy is commonly used to treat cancer, it doesn’t come clean without side effects. Since the drugs used in chemotherapy are strong, it poses mild to severe side effects based on the patient’s health condition.  

Some common side effects include:

• Loss of hair
• Anaemia
• Damage to intestines
• Diarrhoea
• Nausea
• Neutropenia (abnormally low count of a certain type of white blood cells called neutrophils)
• Thrombocytopenia (low level of platelets)
• Gradual weakening of the body
• Abdominal and back pain  

Heavy doses of some drugs may even cause liver damage, kidney failure, pancreatitis, etc.  

What is the goal of chemotherapy?

After knowing that chemotherapy involves various risks associated with it, the obvious question is, “Is chemotherapy worth a try?”

The actual goal of this treatment differs based on the type and level of cancer. If the cancer is in the initial stages, oncologists use chemotherapy to destroy the cancer cells, thus diminishing the disease.  

However, in some advanced cases, this treatment is used to slow down the multiplication of cancer cells and delay the severity of the disease.  

To sum up

Chemotherapy is one of the solid treatments available to fight cancer. Having said that, it also involves mild to severe side effects. Hence the same type of treatment may not be suitable for everybody even if they have the same type of cancer.  

Oncologists prescribe different treatments for different individuals based on their age, body weight, size of the tumour, type of cancer and preferences.  

After every chemo session, healthy communication between you and your doctor would help identify the possible health risk you may experience.