Angiogenesis is the process of forming new blood vessels from existing blood vessels. This is controlled by certain chemicals the body makes. It can help in normal wound healing and supplies oxygen rich blood to organs and tissues.

But the formation of new blood vessels can also help cancer grow. New blood vessels near the cancer cells gives them the oxygen and nutrients they need to multiply and grow into nearby tissue. And it lets them spread to other areas of the body (metastasize).

An angiogenesis inhibitor is a medicine that blocks the signals for the body to form new blood vessels. Scientists have studied these for some kinds of cancer tumors and cells. This is called anti-angiogenic therapy.

This treatment may prevent the growth of cancer. It does this by blocking new blood vessels from forming. This can stop cancer from growing and spreading or it may reduce the size of a tumor.

There are more than a dozen medicines in the United States that are used for this treatment. Most often the angiogenesis inhibitors may work best when used with chemotherapy (chemo) or immunotherapy. These medicines have been approved by the U.S. Food and Drug Administration (FDA) to help treat these types of cancers:

• Recurrent glioblastoma
• Metastatic colorectal cancer
• Non-squamous non-small cell lung cancer
• Liver (hepatocellular) carcinoma
• Neuroendocrine tumors
• Metastatic renal cell cancer
• Cervical cancer
• Ovarian, fallopian tube, and peritoneal cancers
• Stomach cancer
• Thyroid cancer
• Pancreatic cancer

Many chemo medicines kill healthy cells along with cancer cells. But angiogenesis inhibitors only prevent new blood vessels from forming. This means they have different side effects. They can be milder than with some chemotherapy medicines. But some of the side effects can be serious. They can include:

• High blood pressure
• Heart failure
• Internal bleeding
• Diarrhea
• Extreme tiredness
• Rash or dry, itchy skin
• Clots in the arteries that may lead to stroke, heart attack, or decreased heart function
• Poor wound healing
• Low thyroid hormone levels (hypothyroidism)
• Painful swelling and blistering of hands and feet (hand-foot syndrome)
• Protein in the urine
• Bowel perforation (holes in the intestines)

Angiogenesis inhibitors may affect an unborn baby. They are not advised for people who are pregnant or who may become pregnant.