This section will give you a high level review of common non-surgical forms of cancer therapy and related complications. You can also visit our Glossary of Cancer Terms, a comprehensive listing of common terminology and definitions provided by the National Cancer Institute’s Dictionary of Cancer Terms.

Chemotherapy is the treatment of cancer with drugs that can destroy cancer cells by stopping them from growing or multiplying. Healthy cells can also be harmed, especially those that divide quickly. Harm to healthy cells is what causes side effects. These cells usually repair themselves after chemotherapy. Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called combination chemotherapy.

Complications of chemotherapy include fatigue, hair loss, bone marrow suppression such as anemia and neutropenia, skin and mouth lesions, including mucositis, and gastrointestinal symptoms.

Radiation therapy (also called radiotherapy) is the use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy, implant radiation, or brachytherapy).

Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Radiation therapy attacks reproducing cancer cells, but it can also affect reproducing cells of normal tissues. The damage to normal cells is what causes side effects. Radiation therapy involves finding a balance between destroying the cancer cells and sparing the normal cells.

Complications of radiation therapy include fatigue, skin dryness, itching, peeling and damage, mouth inflammation, memory loss, decreased sexual desire, shortness of breath or cough, nausea, vomiting, or diarrhea. Other complications include loss of fertility, and second cancers.

Biological therapy (sometimes called immunotherapy, biotherapy, or biological response modifier therapy) is a relatively new addition to the family of cancer treatments. Biological therapies use the body’s immune system, either directly or indirectly, to fight cancer or to lessen the side effects that may be caused by some cancer treatments. Some antibodies, cytokines, and other immune system substances can be produced in the laboratory for use in cancer treatment. These substances are often called biological response modifiers (BRMs). They alter the interaction between the body’s immune defenses and cancer cells to boost, direct, or restore the body’s ability to fight the disease. BRMs include interferons, interleukins, colony-stimulating factors, monoclonal antibodies, vaccines, gene therapy, and nonspecific immunomodulating agents.

Complications of biological therapies may include rashes or swelling at the injection site, and in the case of interferons and interleukins, flu-like symptoms including fever, chills, nausea, vomiting, and appetite loss. Fatigue is another common side effect of some BRMs. Blood pressure may also be affected. Some of these side effects may be severe, and patients need to be closely monitored during treatment.

We acknowledge the National Cancer Institute as the originator and the NCI website as the source for this information.