Cancer graph skin

Blasting cancer with lasers

Researchers have found two new ways to use lasers against cancer.

Photodynamic therapy involves a drug that only malignant cells pick up. When activated by light from a laser, the drug destroys the malignant cells.

This technique, offered only at the Stanford (Calif.) University Medical Center, is currently reserved for patients whose breathing has been impaired by lung or esophageal cancer. Although not a cure, the treatment can ease symptoms in patients who are too frail for surgery and in those whose cancer has progressed too far for traditional therapy.

In most cases, patients needn't be hospitalized to undergo the technique, which involves threading a thin fiber-optic probe into the esophagus or bronchial tubes. Following the therapy, patients must avoid prolonged and intense exposure to light for 4 to 6 weeks because their skin would burn easily.

The U.S. Department of Energy, in an attempt to develop new semiconductor technology, has "accidentally" developed a dime-sized laser that detects cancer cells in seconds. Still under development, the laser may someday help surgeons excise only malignant tissue and spare healthy tissue.

When cells pass through its channels, the so-called smart scalpel can quickly identify a malignancy. Cancer cells are denser than normal cells, which slow the speed of laser light passing through them. A graph on a laptop computer registers the presence of cancer cells. Because the device can analyze up to 100,000 cells per second, surgeons can quickly tell when the incision is free from malignant cells.

Within the next 2 years, developers expect to have a prototype ready for clinical testing.