How They Work

Targeted therapies are designed to block or interfere with specific substances, like VEGF. These substances, also called growth factors, help tumor cells grow and spread. Unlike radiation or chemotherapy, which attack both cancer and healthy cells, targeted treatments spare most healthy cells because they follow very specific pathways.

There are several types of targeted therapies, and they all work in different ways. Targeted therapies may affect cancer cells by:

• Causing cancer cells to die or "commit suicide" (called apoptosis)
• Blocking important cell processes that help cancer cells survive
• Preventing or reducing the activity of growth factors that help cancer cells to grow
• Stopping the formation of new blood vessels (anti-angiogenesis)

Targeted therapies are approved for use alone or in combination with chemotherapy, depending on the type and stage of a patient's cancer. Studies are being conducted to see how other cancer therapies may be combined with targeted therapies to treat many different types of cancer.

Side Effects

Since targeted therapies attack cancer cells and usually have a limited affect on normal cells, they may have fewer, less severe or different side effects than other treatments such as chemotherapy and radiation. Side effects may include: allergic reactions, fatigue, fever, chills, headaches, nausea, diarrhea, rash and blood pressure changes. Rare or more serious side effects can include an increased risk of bleeding, infection and heart problems.

Because these treatments are newer than chemotherapy, doctors are still learning about their potential risks and how to manage them. As always, be sure to talk with your doctor about any side effects.