Photodynamic Therapy (PDT) of the Endometrium to Arrest Abnormal Uterine Bleeding

Selective laser treatment of the endometrial lining may soon offer women who suffer abnormal uterine bleeding a non-surgical, outpatient procedure which arrests the course of their disorder. While oncologists have used photo-dynamic therapy (PDT) to treat discrete tumors for more than a decade, medical researchers at the Beckman Laser Institute are the first to successfully apply the technique to gynocologic medicine. In collaboration with physicians from the University of ZŸrich, Institute researchers, Yona Tadir, M.D. and Bruce J. Tromberg, Ph.D., have pioneered a novel application of PDT which may transform womens' health care entirely.

"More than 100,000 hysterectomies are performed each year to treat dysfunctional uterine bleeding which may accompany menopause," states Dr. Tadir, Medical Director of the Beckman Laser Institute. "These are major procedures with long recovery periods and the possibility of severe complications. I am confident that a significant number of these surgeries can be avoided with the application of this new technique."

PDT typically involves the intravenous or topical administration of photoactive compounds known as photosensitizers. When light of sufficient energy and appropriate wavelength interacts with a sensitizer, highly reactive oxygen molecules are generated which irreversibly oxidize cells and tissues in which the sensitizers have concentrated. In the case of endometrial PDT, selective destruction of lesions on the uterine lining can be employed effectively to manage abnormal bleeding. Healthy tissues surrounding the lesions are not affected by the treatment.

"We have studied a number of photo-sensitizers in experimental models which are well suited to the procedure, and these can be delivered topically for better drug uptake and enhanced localization," comments Dr. Tadir. "With regard to endometrial PDT, I am talking about a novel, minimally invasive therapy. It's a non-surgical procedure with decided advantages over expensive hormone treatments and surgery."

Dr. Tadir and his collaborators have recently developed a laser endoscope (probe) designed specifically for endometrial PDT. The Light Intra-Uterine Device (L-IUD) can be used to illuminate the uterine cavity internally, without pain or complications, and will play a crucial role in future tests to optimize laser treatment parameters.

A new series of clinical trials is planned to test the technique's efficacy for two closely related gynecological disorders, endometriosis and endometrial cancer. "Endometrial PDT," says Dr. Tadir, "should offer safer, less expensive treatment for a significant, commonly occurring medical condition among women." The endometrial layer of the human uterus is particularly well suited to PDT. A variety of sensitizers which perform effectively when administered topically are already available. In addition, Yona Tadir, M.D., Medical Director of the Beckman Laser Institute and Bruce J. Tromberg Ph.D., Assistant Professor of Surgery and Physiology/Biophysics, are the first to successfully apply the technique to gynecologic medicine.