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July 17, 2006 -- An experimental treatment that uses image-guided radiofrequency waves to kill tumors appears to be highly effective in prolonging the lives of early stage lung cancerlung cancer patients who are not candidates for surgery.
The average three-year survival among 41 patients treated with radiofrequency ablation (RFA) combined with traditional radiation therapy was 3.5 years. That is longer than survival typically seen among similar patients treated with radiation therapy alone, interventional radiologist and RFA pioneering researcher Damian Dupuy, MD, tells WebMD.
Only about 60 lung cancercancer patients worldwide have been treated with the combination of RFA and radiation, but Dupuy says their results suggest that the two treatments provide better results than either therapy alone.
"I have been all over the world within the last five years telling this story," he says. "Radiation and thermal ablation should be combined. The synergy from both a theoretical and clinical standpoint is too compelling to ignore."
How RFA Works
Approved for use in the U.S. in 1997, radiofrequency ablation has also been used experimentally in the treatment of patients with liver, kidney, colon, and bone cancers who weren't good candidates for other therapies.
RFA involves the positioning of an image-guided needle within the tumor. High levels of radiofrequency energy are sent through the needle in an effort to kill tumor cells with heat while leaving surrounding tissue relatively unharmed.
It is a minimally invasive procedure, which is generally done in an outpatient setting, says Dupuy, who is director of ultrasound at Rhode Island Hospital and a professor of diagnostic imaging at Brown Medical School in Providence.
Survival Rates
Dupuy and colleagues retrospectively examined outcomes among 41 patients with non-small-cell lung cancerlung cancer (the most common type of lung cancercancer) treated at Rhode Island Hospital over a seven-year period. All of the patients in the study had early stage tumors, but they were considered ineligible candidates for lung surgery to remove their tumors. Most had other medical conditions, such as emphysemaemphysema, making the risk of surgery too dangerous.
There are about 165,000 new lung cancers diagnosed each year in the U.S.; in about 10% of cases patients have early stage disease but are considered medically inoperable, Dupuy says.
All of the patients in the study had RFA followed by radiation, usually given within a month.
The overall survival among the patients was 87% at one year, 70% at two years, and 57% at three years. The researchers compared these findings with those from a 1990 study involving patients with similar characteristics treated with radiotherapy alone, in which the overall survival was 57% at one year, 36% at two years, and 21% at three years.
The study was published in the July issue of the Journal of Vascular and Interventional Radiology.
Can't Say It's Better
The experimental combination therapy has not been directly compared with radiation alone in medically inoperable lung cancer patients with localized disease. Until these studies are done, it will be impossible to say that it is better or worse than the current recommended initial treatment, American Cancer Society spokesman Len Lichtenfeld, MD, tells WebMD.
"It is not appropriate for patients or physicians to conclude from this study that RFA and radiation is better than radiation alone, because that is not what they looked at," he says.
Lichtenfeld says RFA is being used more and more to treat various cancers, but it has not been shown to be particularly effective as a single therapy for the treatment of lung cancer.
He calls the combination approach intriguing but adds that it is not clear if treatment outcomes would be as good in patients who were not as carefully selected as those included in the study.
"This is an informative and interesting study, and it certainly demonstrates that this treatment can be effective. It is worthy of further investigation but until a direct comparison is done we can't say that it is better."
SOURCES: Dupuy, D. Journal of Vascular and Interventional Radiology, July 2006; vol 17: online edition. Damian Dupuy, MD, director of ultrasound, Rhode Island Hospital; professor of diagnostic imaging, Brown Medical School. Len Lichtenfeld, MD, deputy chief medical officer, American Cancer Society. Talton et al., International Journal of Radiation Oncology Biology Physics,1990; vol 19: pp 15-21.