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.From the Thomas Jefferson University Hospital :Jefferson Surgeons Turning to Light Therapy for Advanced Lung Cancer
Surgeons at Thomas Jefferson University Hospital in Philadelphia 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.
Non-small cell lung cancer (NSCLC) is one of the most difficult cancers to treat, particularly when it spreads to the lining of the chest cavity. Even if the cancer is operated on, the disease returns in as many as 90 percent of patients. Survival frequently is measured in months. Results with chemotherapy – the current standard of care – are disappointing, with most patients living only between six and nine months.
Joseph Friedberg, M.D., is trying another way. Dr. Friedberg, chief of thoracic surgery at Thomas Jefferson University Hospital and Jefferson’s Kimmel Cancer Center, is leading a clinical trial examining the effects of light, or more specifically, photodynamic therapy (PDT), on this type of advanced NSCLC. Such patients have cancer that has “broken out of one lung and seeded the lining of the chest cavity,” he explains.
In 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.
The surgeons present their results November 6 at CHEST 2002, the annual meeting of the American College of Chest Physicians in San Diego.
The results, he says, have far surpassed expectations. “We had hoped the PDT would be effective in decreasing the local recurrence rate and it has,” Dr. Friedberg says. “It surprised us that we appear to have made such an impact on survival.
“The numbers are small, and it’s only preliminary,” he says. “But if these results continue, this would be a significant advance in the treatment of this type of lung cancer.”
Why they are seeing such good results is something of a mystery. PDT has typically been used by clinicians for treating small, easily seen tumors. The Jefferson trial for this type of lung cancer currently is the only one of its kind in the world.
“Traditionally, PDT has been used as a local therapy,” Dr. Friedberg says. “The light passes only a few millimeters under the skin. It is approved by the Food and Drug Administration for use in endobronchial cancers, esophageal cancer and some skin cancers. It makes sense that it would reduce local recurrence rates, but why should it have such an apparently impressive impact on survival?”
Dr. Friedberg is hoping to use basic science research to better understand some of the cancer-killing effects of PDT he has seen in his patients. He is planning to collaborate with researchers at the University of Pennsylvania and at Roswell Park Cancer Institute in Buffalo to study the effects of photodynamic therapy on the immune system.
“We’re the only ones doing this right now,” he says. “And there’s a lot of work and a lot of science left to do before we can validate these preliminary results and explain the favorable impact we are seeing.”
