An ingenious type of surgery involving the attachment of a tiny bowlful of radioactive material to the surface of the human eye has begun to save the vision of Utahns stricken by eye tumors.
Episcleral plaque radiotherapy, used to treat patients with choroidal malignant melanoma, the most common inter-eye tumor, previously was available only at clinics hundreds of miles away. Most Utah residents who had the relatively-new surgery had to travel to San Francisco.Now this specialized surgery is offered at LDS Hospital, Eighth Avenue and C Street, said Dr. Kirk W. Winward, an ophthalmologist there.
A team headed by Winward has performed three such operations - the most recent last week - "but it hasn't been done in the area before," he said. The procedure has been available elsewhere for about 15 or 20 years.
Last Friday's operation went "just as hoped," he said afterward.
"It's always six months before you see the tumor actually shrink, but she's doing real well so far," he said Tuesday, speaking of the patient.
Until now, the technical ability to construct the plaques wasn't available locally. But Dr. William T. Sause, a radiation oncologist at LDS Hospital, and his staff traveled to Philadelphia for training at the Will's Eye Institute.
Utah physicians also obtained computer software that allows for extremely accurate radiation calculation and helps design the plaques, said Jess Gomez, spokesman for LDS Hospital.
Winward, who was trained in Miami, said that in the past, a common treatment with the melanoma was removing the eye. More recently, physicians tried to develop ways to treat the tumor without radiation, without removing the eye.
"Those types of treatments work only for the very smallest tumors," he said. However, most often the cancer isn't recognized until the tumor is too large for standard radiation treatment.
The amount of radiation needed to kill a large tumor, if delivered to the entire eye, could damage the eye so badly that vision is lost anyway. That has now changed, however.
"The new surgery is a way of treating the tumor with radiation in such a way that you can try to concentrate the radiation at the site of the tumor and minimize damage to other structures in the eye."
A plaque - a shallow, carefully crafted bowl lined with gold - is central to the operation. The gold blocks radiation that might otherwise damage other parts of the eye.
The plaque is filled with pellets of radioactive material and sutured to the outside of the eye, "directly overlying the tumor," Winward said.
"Therefore the tumor can receive a real high, intense dose of radiation, enough to destroy the tumor." Meanwhile, "hopefully, the other tissues of the eye get very little or none at all."
The plaque usually is left in place for three to five days. The length depends on the size of the tumor and how radioactively "hot" the pellets - called seeds - are.
Oncologists calculate the length of exposure and dosages needed to kill particular kinds and sizes of tumors, then construct the plaque.
How are the patients doing? It's too early to tell whether the most recent procedure will destroy the tumor that the third patient has. But "the first two have both done very well - had nice tumor shrinkage," Winward said.