For example, breast cancer that spreads to the lung interferes with oxygen uptake, resulting in muscle pain, dizziness and ultimately, death. As cancer researchers look for new treatments, a common objective is to prevent, reverse, or slow metastasis. Researchers have made major advances in chemotherapy over the last three to four decades, especially in curing leukemia, lymphoma, Hodgkin's disease and testicular cancer. In the last 10 to 15 years, chemotherapeutic agents made by microorganisms or plants have replaced nitrogen mustard, methotrexate, and other such compounds used in chemotherapy. Brachytherapy is a new therapy that involves placing radioactive pellets either directly into a tumor or within a catheter in the body, providing a controlled dose of radiation to the tumor.
Physicians sometimes combine brachytherapy with conventional radiation therapy.
A newer class of drugs helps the immune system ward off cancer. These immuno-modulators are cells or substances called serum factors that augment the patient's natural immunity against cancer. Interferon is a cancer-fighting substance that occurs naturally in the body. Doctors are just beginning to use it to treat a very rare blood cancer called hairy-cell leukemia. Gene therapy is based on the experimental concept of correcting a genetic defect by supplying a patient with a healthy copy of a gene.