What is Chemotherapy?

What is Chemotherapy?

Chemotherapy is a type of cancer treatment that uses drugs to kill cancer cells. These drugs target cells that grow and divide quickly. Since cancer cells grow faster than most normal cells, chemotherapy focuses on stopping them. However, some healthy cells—like those in the hair, digestive system, and bone marrow—also divide quickly, so they can be affected too. This leads to side effects like hair loss, nausea, tiredness, and a higher risk of infections.

How Chemotherapy Works

Chemotherapy drugs interfere with how cancer cells grow and divide. Since cancer cells multiply without control, these drugs are designed to slow or stop this growth. Unfortunately, because the drugs also affect healthy fast-dividing cells, side effects often occur in other parts of the body.

Types of Chemotherapy

There are several classes of chemotherapy drugs, each working in unique ways:

• Alkylating agents: Damage DNA to stop replication (e.g., cyclophosphamide, cisplatin)
• Antimetabolites: Mimic cell building blocks and disrupt DNA formation (e.g., methotrexate, 5-fluorouracil)
• Anti-tumor antibiotics: Prevent DNA from unwinding and replicating (e.g., doxorubicin)
• Mitotic inhibitors: Stop cell division by targeting microtubules (e.g., paclitaxel, vincristine)
• Topoisomerase inhibitors: Block enzymes that help DNA replicate (e.g., etoposide, irinotecan)

Uses of Chemotherapy

Chemotherapy is used in various ways:

• Curative chemotherapy: Aims to completely eliminate cancer.
• Adjuvant chemotherapy: Given after surgery/radiation to kill leftover cancer cells.
• Neoadjuvant chemotherapy: Given before surgery/radiation to shrink tumors.
• Palliative chemotherapy: Used to relieve symptoms and improve comfort in advanced cancer cases.

Side Effects of Chemotherapy

Because chemotherapy impacts healthy fast-growing cells, common side effects include:

• Hair loss due to affected hair follicles.
• Nausea and vomiting from digestive tract irritation.
• Fatigue, often due to lower red blood cell counts.
• Weakened immunity from reduced white blood cells.
• Mouth sores and neuropathy (tingling or numbness in hands/feet).

How Chemotherapy Is Given

Chemotherapy can be administered in different forms:

• Intravenous (IV) infusion into a vein.
• Oral tablets or capsules.
• Injection into muscles or under the skin.
• Topical creams for skin cancers.
• Intrathecal (into the spinal fluid) or intraperitoneal (into the abdomen) routes for certain cases.

Chemotherapy remains a powerful tool in the fight against cancer, and ongoing research continues to improve its precision and reduce its side effects.