Science / Medicine : Light Aids Cancer Treatment

A drug activated in the body by light can destroy cancer without harming normal tissue, say U.S. doctors who experimented with the therapy in China. In a report in the New England Journal of Medicine, doctors from Massachusetts General Hospital described their use of the treatment to help people with bladder cancer.

Similar applications of this approach, called photodynamic therapy, have been used to treat tumors of the lungs and esophagus, as well as recurring breast cancer.

Doctors first injected patients with a drug called hematoporphyrin. After waiting two days, the physicians shine light on the cancerous cells in the lining of the bladder. The light excites the hematoporphyrin that remains in these cells. This kills the cancer cells, but normal cells that do not contain hematoporphyrin are spared.