What are the different types of systemic therapies?

October 2, 2025 •

3 min read

Systemic therapy has fundamentally changed cancer medicine, offering hope with treatments once considered impossible to cure. The different types of systemic therapies provide powerful, medication-based approaches to targeting disease throughout the body.

Quick Summary

Systemic therapies use medication to target disease throughout the body. The main types include chemotherapy, targeted therapy, immunotherapy, and hormone therapy, each working differently to combat illness.

Key Points

Chemotherapy: Uses powerful cytotoxic drugs to kill rapidly dividing cells throughout the body, including healthy ones.
Targeted Therapy: A precision medicine approach that specifically targets molecular pathways or genetic mutations in cancer cells, often resulting in fewer side effects.
Immunotherapy: Harnesses and enhances the body's own immune system to recognize and attack cancer cells more effectively.
Hormone Therapy: Blocks or removes hormones that are essential for the growth of certain types of cancer, such as breast and prostate cancer.
Considerations for Treatment: The choice of therapy depends on the cancer type, stage, and individual patient factors identified through testing and clinical evaluation.
Whole-Body Impact: All systemic therapies work by entering the bloodstream to affect the body as a whole, differentiating them from localized treatments like surgery.

Understanding Systemic Therapy

Systemic therapy refers to any treatment that uses medication to affect the entire body by traveling through the bloodstream. Unlike localized treatments like surgery or radiation, which focus on a specific area, systemic therapies can reach cells and tissues anywhere in the body. This makes them especially crucial for treating diseases that have spread or for eliminating stray cancer cells after a localized treatment. For diseases like cancer, this approach is vital for ensuring comprehensive treatment.

Chemotherapy: The Traditional Powerhouse

Chemotherapy is a traditional type of systemic therapy using cytotoxic drugs to kill rapidly dividing cells, including cancer cells. This broad action also impacts healthy cells, causing side effects. Chemotherapy agents are categorized based on their mechanism, such as alkylating agents that damage DNA or antimetabolites that interfere with DNA/RNA growth. Other types include antitumor antibiotics and mitotic inhibitors.

Targeted Therapy: Precision Medicine

Targeted therapy, or precision medicine, is a newer systemic approach focusing on specific molecular targets in cancer cells. This leads to more selective treatment and potentially fewer side effects than chemotherapy. Targeted therapies include monoclonal antibodies, large proteins binding to targets outside cancer cells, and small-molecule drugs that enter cells to disrupt growth pathways. Examples of monoclonal antibodies include rituximab or trastuzumab, while small-molecule drugs include imatinib or bortezomib.

Immunotherapy: Harnessing the Body's Defenses

Immunotherapy utilizes the body's immune system to fight disease, often by helping it recognize and attack cancer cells. Key types involve immune checkpoint inhibitors that release the brakes on the immune response (e.g., pembrolizumab), CAR T-cell therapy where a patient's own immune cells are modified to target cancer, and cytokines that signal immune cells to be more active.

Hormone Therapy: Blocking Fuel for Cancer Growth

Hormone therapy is a systemic treatment for cancers that depend on hormones, like some breast and prostate cancers. It works by reducing hormone production or blocking their effects on cancer cells. Approaches include anti-estrogens like Tamoxifen for breast cancer, aromatase inhibitors to lower estrogen, and androgen deprivation therapy (ADT) for prostate cancer.

Comparison of Systemic Therapies


Feature	Chemotherapy	Targeted Therapy	Immunotherapy	Hormone Therapy
Mechanism	Kills rapidly dividing cells throughout the body.	Blocks specific molecular pathways in cancer cells.	Boosts the body's immune system to fight cancer.	Blocks or removes hormones that fuel cancer growth.
Selectivity	Low (affects healthy and cancer cells).	High (targets specific cancer cell characteristics).	High (uses the immune system's natural selectivity).	High (targets hormone-sensitive cancer cells).
Side Effects	Often widespread (hair loss, nausea, fatigue) due to affecting healthy cells.	Generally more specific, but can vary greatly (e.g., skin rash, liver problems).	Can cause immune-related side effects, mimicking autoimmune diseases.	Related to hormone disruption (e.g., hot flashes, fatigue).
Common Use	Many cancer types, often combined with other treatments.	Cancers with specific genetic mutations or protein targets.	Advanced or metastatic cancers, particularly melanoma and lung cancer.	Hormone-sensitive cancers, like breast and prostate cancer.

Deciding on a Treatment Plan

Selecting the appropriate systemic therapy involves assessing several factors with your cancer care team. These include the specific type and stage of cancer, results from biomarker testing to identify potential targets, your overall health, treatment objectives (curative or palliative), and any previous treatments. Your healthcare team will work with you to choose the best option, considering effectiveness and managing potential side effects. For further information on cancer treatments, the National Cancer Institute is a valuable resource.

Conclusion

Systemic therapies are vital in modern medicine, providing body-wide treatment for diseases. From chemotherapy's broad action to the precision of targeted therapy, the options are advancing. Each therapy type has distinct benefits and potential side effects. Current oncology focuses on personalized treatment plans tailored to individual patient needs and the specific characteristics of their illness. Ongoing research continues to enhance these therapies, improving outcomes for patients with complex diseases.

Frequently Asked Questions

Localized therapy, such as surgery or radiation, treats a specific area of the body. In contrast, systemic therapy uses medications that travel through the bloodstream to treat disease throughout the entire body, including areas where the disease may have spread.

No. While both use drugs to fight disease, targeted therapy focuses on specific molecular targets found on cancer cells, leaving healthy cells relatively unharmed. Chemotherapy is less selective, killing most rapidly dividing cells, both healthy and cancerous.

Immunotherapy stimulates or enhances the immune system to help it better recognize and attack cancer cells. It can remove the "brakes" on the immune response or add engineered cells that are trained to fight the cancer.

Hormone therapy is primarily used for cancers that are sensitive to and depend on hormones for growth. This includes certain types of breast and prostate cancer.

No. The side effects vary greatly depending on the specific therapy. Chemotherapy often causes widespread side effects like nausea and hair loss, while targeted and immunotherapies can have more specific or immune-related side effects.

The choice of therapy depends on the cancer type, stage, and specific biomarkers identified through testing. A patient's overall health and treatment goals are also important considerations.

Yes. It is common for oncologists to use a combination of different systemic therapies or combine them with localized treatments like surgery or radiation to achieve the best possible outcome.