Last year Paul Okunieff, M.D., and colleague Alan Katz, M.D., working at University of Rochester’s Medical Center, reported using the technology to achieve an 88 percent control rate for metastatic tumours in the liver, a result that was considered highly unlikely as recently as five years ago.

In the study of 50 patients, 91 percent of the lung tumours treated between February 2001 and December 2005 never progressed, and about 25 percent of patients appear to be disease-free after three years of follow-up. Doctors hope that shaped-beam radiosurgery and chemotherapy might form a "synergistic combination that allows the drugs to destroy the microscopic cells that imaging studies can't see while the radiation therapy controls the tumours we can see," said Okunieff.

Perhaps most importantly, this high-dose, focused radiation targets the tumour with very limited damage to healthy tissue that surrounds the lesion, and patients experience minimal side effects even when a large number of tumours are treated, Okunieff said. "We're getting better and better at finding smaller and smaller tumours that we can irradiate easily, and people are living longer," Okunieff said.

Okunieff's current study focused on patients with multiple lung lesions ranging in size from three millimetres to 7.7 centimetres. Doctors treated 31 people with fewer than five tumours curatively and 19 others with more than five lesions palliatively to slow the disease. These patients had undergone multiple previous therapies for their metastatic disease prior to radiosurgery.

Three years after follow-up, of the 125 lesions treated, 36 lesions (29 percent) disappeared completely, 32 lesions (26 percent) had shrunk, and 49 (39 percent) were stable after treatment. Eight of the 125 lesions (6 percent) grew larger after the radiosurgery.

MEDICA.de; Source: University of Rochester