The womans left lung had collapsed because a tumor blocked the airway leading to it. She could only survive in a hospital with the help of a machine that forced air into her lungs. This unfortunate condition made her an ideal candidate for a new procedure known as photodynamic, or light, therapy.
Raphael Bueno, a surgeon at Brigham and Womens Hospital in Boston, eased a bronchoscope into the airway leading to the damaged lung. He turned on a laser that fed high-intensity red light into the scope and to the obstructive tumor.
Bueno did the procedure twice, and in a few weeks X-rays showed that the womans lung was fully functional. She went home from the hospital without any need for supplemental oxygen.
The operation was one of more than 30 such procedures Bueno has done since photodynamic therapy was approved by the Food and Drug Administration in December 1998.
The FDA has also given a green light to using lasers for treatment of advanced stages of cancer of the esophagus, a 9-inch pipe leading from the mouth to the stomach. A surgeon can use lasers to shrink a tumor blocking an esophagus in about 15 minutes, as opposed to a five-hour operation to remove it by surgery. The light treatment saves the esophagus and eliminates a need for tube feeding.
“The purpose of photodynamic therapy is not to cure anyone,” says Bueno, who is an instructor in surgery at Harvard Medical School. “The majority of our patients are incurable. Their tumors cannot be reached by surgery, or treated successfully with radiation or chemotherapy. What we want to do is to help them become as functional and independent as possible for as long as possible.”
The woman whose collapsed lung was inflated lived another five months before the cancer spread to her brain and killed her. Other patients have enjoyed life extensions of 12 to 24 months.
Bueno believes that such increases of functional life can be turned into opportunities for more curative treatments. “The majority of patients with advanced lung cancer are so short of breath they cannot get to radiation or chemotherapy facilities, or are not well enough to tolerate these therapies,” Bueno comments. “I have started to test the safety and efficacy of combining photodynamic therapy with other types of treatments in the hope of prolonging patients lives even longer.”
Early Stage Cures
Light treatment has been approved for both advanced and early stage lung cancer. It hasnt been used much for the latter because its so difficult to detect the earliest stages of the disease. Thats why lung cancer is the biggest cancer killer in the United States. It kills more Americans than breast or prostate cancer, primarily because by the time its detected, lung cancer is in its advanced stages.
“We dont have efficient ways to detect changes in the lungs that will eventually become cancer,” Bueno points out. “If we did, we could eliminate much suffering and extend many lives. People might die with lung cancer instead of because of it.”
In the case of cancer of the airways, which lead from the mouth and nose to the lungs, the few treatments that have been done indicate early tumors can be cured with light therapy. “I and others who use photodynamic therapy intend to pursue early identification and treatment of airway lung cancer more aggressively,” Bueno says. “We want to screen people for lung cancer the way physicians now use mammograms to find breast cancer and a blood test to detect prostate cancer.”
He intends to use a combination of bronchoscope and laser to spot changes in the lining of airways that could eventually become cancers. Called a “Lifescope,” this device will be combined with CAT scans, which use X-rays and computers to construct three-dimensional images of suspicious changes. These areas might then be “melted” away with laser light.
Bueno will try this method first on patients who have had lung cancer and are at high risk of its recurrence. Such trials could begin as soon as spring of this year. “If we catch the cancers early enough, we should get a cure rate of about 80 percent,” Bueno predicts.
Killing Tumors with Light
Light therapy starts with injection of a drug known as Photofin. The drug goes into all cells of the body, but normal cells excrete it in about two days. Tumor cells retain it, however, for reasons no one is sure of. Two days after the injection, surgeons pass a scope, which is connected to a laser machine by a fiber optic cable, down the patients airway. Placement must be such that the light is delivered next to the tumor.
“When the medicine in the tumor sees the light, it releases toxic oxygen radicals that kill tumor cells,” Bueno explains.
Patients return after two days for a second treatment. They usually begin to breathe more easily in two, or even one week. Bueno claims a success rate of 80 percent.
This novel therapy is available in a limited number of places throughout the country. Harvard-affiliated Brigham and Womens Hospital is one of the largest centers. “We probably do the most procedures,” says Bueno. Other centers include teaching hospitals affiliated with the University of Pittsburgh, Duke University in North Carolina, and Beth Israel Deaconess Medical Center in Boston.
Researchers have also been testing light therapy on other types of cancers, including skin and breast, for which it is not yet approved. “I have used it, and so have others, on various types of cancers that have spread from other areas to lung airways,” Bueno notes. “So we know it can work on different cancers. But you must get the light source next to the tumor, something that cant be done in a solid organ like the kidney or liver. Thats why its not a magic bullet.”
More information is available at http://www.chestsurg.org. Clicking on “photodynamic therapy” brings up images of lungs before and after treatment, including those of the woman mentioned at the beginning of this article.