Laser Therapy Shows Long-Term Effectiveness for Melanoma of the Eye

Friday, April 14, 2006

ROCHESTER, Minn. — Mayo Clinic researchers report that transpupillary thermotherapy (TTT) appears to be a successful treatment for most patients who have small choroidal melanomas — a primary cancer of the eye. The results of the study are in the April issue of Archives of Ophthalmology.

In TTT, a wide laser beam is directed at the choroidal tumor through a contact lens, causing tumor cell death. In 1996, Mayo became one of the first centers in the nation to use TTT. Three years later, Mayo researchers published the results of TTT for the first 20 patients seen (available online at http://archopht.ama-assn.org/cgi/content/full/117/11/1512).

"We wanted to reaffirm the effectiveness of TTT for our original patients by examining their follow-up data," said Colin McCannel, M.D., Mayo Clinic ophthalmologist and study co-investigator. "In addition, we hoped to show continued success with the procedure as a stand-alone treatment for choroidal melanoma."

The choroid is the vascular layer of the eye between the retina and the sclera. It is responsible for limiting reflection of light within the eye as well as providing blood supply and oxygen to the retina. Choroidal melanoma can cause vision loss and eventually spread to other parts of the body. While cancers of the eye are not very common, they historically were treated by removal of the eye to prevent spread of the cancer. There are limited treatment options beyond removing the eye, but the Mayo team showed that at least for small tumors, TTT is a very good option.

In addition to reviewing follow-up information from the original 20 patients, the researchers also reviewed the data from 20 patients whose treatment occurred between 1999 and 2002. Of the original 20 patients, with an average follow-up of 57 months, 16 showed no recurrence. Three required between one and three repeat TTTs, and a fourth had continued tumor growth that subsequently required radiation therapy.

Similar results were found with the more recent 20 patients. Only two required additional treatment (one TTT, one cryotherapy — killing the cancer cells by freezing them) to be free of the cancer. Three other patients did not respond sufficiently to TTT. Of these, two had the eye removed, and one required radiation therapy.

Overall, 77.5 percent (31) tumors were successfully treated with one TTT. An additional five patients had recurrences that were treated with more TTT or cryotherapy, resulting in an overall 90 percent cure rate.

"These results are continued good news for patients with choroidal melanoma," said Dr. McCannel. "We can save eyes and maintain vision with this procedure." He cautions that this surgery is only an option for patients who have small tumors that have not spread beyond the choroid.

Other Mayo researchers involved in this study were Peter Win, M.D.; Dennis Robertson, M.D.; and Helmut Buettner, M.D. They collaborated with Steven Bennett, M.D., from VitreoRetinal Surgery, PA, Minneapolis, Minn.

For further information on the treatment of ocular melanoma at Mayo Clinic, visit: http://www.mayoclinic.org/melanoma/ocular.html.

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