Chemotherapy attacks rapidly dividing cells and has been a key cancer treatment since the 1940s. It causes side effects such as hair and nail changes, low blood counts, nausea, and neuropathy. Advances in supportive care and the development of targeted and immune therapies have reduced some harms and expanded options, yet chemotherapy continues to be used alone or with surgery and radiation depending on the cancer and treatment goals.
What chemotherapy is and how it works
Chemotherapy uses drugs that target rapidly dividing cells. That includes many cancer cells, which multiply faster than normal tissue. Because these drugs act on cell division, they can damage healthy fast-growing cells as well - for example, hair follicles, the lining of the mouth and gut, and blood-forming cells in the bone marrow.
Chemotherapy has been in clinical use since the 1940s and remains a core cancer treatment. On its own or combined with surgery and radiation, it can shrink tumors, control disease spread, and improve survival in many cancers.
Common side effects and how we manage them
Hair loss and nail changes are visible and common chemotherapy effects because those tissues renew quickly. Other common side effects include nausea, fatigue, low blood counts (which raises infection and bleeding risk), and peripheral neuropathy (tingling or numbness). Severity and specific symptoms depend on the drugs and doses used.
Modern supportive care reduces many side effects. Antiemetic medications control nausea. Growth factor injections (for example, G-CSF) help recover white blood cells. Scalp cooling can reduce the risk of hair loss for some regimens. Fertility preservation, dental care, and nutritional support are routinely discussed before treatment begins.
Toxicity and risk
Some chemotherapy drugs can be harsh and cause serious short- and long-term toxicities. Oncologists weigh the potential benefits against these risks when recommending treatment. Monitoring and dose adjustments, along with supportive medications, reduce the chance of severe harm.
Newer treatments and when chemo is still used
Since the 2000s, oncology has expanded beyond classical chemotherapy. Targeted therapies (which act on specific molecular features of tumors), hormonal treatments, and immunotherapies (which boost the immune system to fight cancer) have transformed care for many cancer types.
These newer approaches do not eliminate chemotherapy. Many patients still receive chemotherapy as the main treatment, or in combination with surgery, radiation, targeted drugs, or immunotherapy. Chemo is often used as:
- Neoadjuvant therapy (before surgery) to shrink tumors.
- Adjuvant therapy (after surgery) to lower recurrence risk.
- Palliative therapy to relieve symptoms and slow disease progression.
Talking with your care team
If you or a loved one faces chemotherapy, ask about the specific drugs, likely side effects, available supportive measures, and goals of treatment (curative vs. control). Ask whether newer targeted or immune-based options are appropriate for your cancer type and whether fertility or other long-term risks should be planned for.