photodynamic therapy
San Diego, CA -- A combination of medications and a particular light therapy is effective at treating certain types of head and neck cancers in subtropical climates.
SANTA CRUZ, CA--Chemists at the University of California, Santa Cruz, have developed novel compounds that show promise for photodynamic cancer therapy, which uses light-activated drugs to kill tumor cells.
NEW YORK (May 29, 2009) -- Patients who have gastroesophageal reflux disease (GERD) for a prolonged period have an increased risk of developing Barrett's esophagus, a pre-cancerous condition where the tissue lining the esophagus becomes damaged by stomach acid and transformed into something like the inside of the stomach.
The viscosity, or 'gloopiness', of different parts of cancer cells increases dramatically when they are blasted with light-activated cancer drugs, according to new images that provide fundamental insights into how cancer cells die, published in Nature Chemistry today (15 March).
As the scientific community is seeking alternatives to antibiotic treatment, periodontal researchers found that photodynamic therapy is advantageous for suppressing anaerobic bacteria that lead to periodontal diseases. PDT involves two stages. In the first stage, a light-sensitive drug is applied. The second stage involves shining a light or laser directly on the area treated with the drug. When the light is combined with the drug, phototoxic reactions are induced which destroy bacterial cells. PDT was first approved by the Food and Drug Administration in 1999 to treat pre-cancerous skin lesions of the face or scalp.
Gastroenterologists at Mayo Clinic in Jacksonville, Fla., report photodynamic therapy (PDT) appears to destroy the abnormal tissue of Barrett's esophagus as well as superficial esophageal cancer. Here's how PDT works. Patients are given an injection of a photosensitizing drug called porfimer sodium (Photofrin). Cells in the body absorb this drug. Normal cells get rid of it, but the drug tends to collect in premalignant and malignant cells. Two days after the injection of Photofrin, physicians insert and endoscope into the sedated patient's esophagus. An endoscope is a thin, flexible tube with a miniature camera on its tip. Physicians deliver a specific wavelength of red laser light through the endoscope to the targeted cells. The laser light destroys the Photofrin-containing cells. Normal esophageal cells grow back in their place.
Surgeons in Philadelphia say they are finding success by combining light-based cancer therapy with surgery to treat patients with advanced lung cancer that has spread within the chest. While the number of patients treated to date is small, many patients are living three to four times longer than did those patients who did not receive the therapy. In photodynamic therapy (PDT), a nontoxic photosensitizing agent, photofrin, is injected into the bloodstream and absorbed by cells all over the body. These compounds tend to concentrate more in cancer cells than in normal cells. When the compound is exposed to a certain wavelength of light, it absorbs the light energy and produces a form of oxygen that kills the cells. The damage occurs only where the light is shined. In the study, each patient is given chemotherapy until the cancer stops responding, meaning the disease begins to grow again. If the cancer has not spread beyond the chest, the patient then receives photofrin 24 hours prior to surgery to remove the tumor. During surgery, he or she receives an appropriate dose of light therapy. Of the 16 patients evaluated to date, at least one-half have lived more than 23 months, which is between three and four times the usual time.
