New center arises from success of radioactive-implant therapy

Last year, physicians in the Department of Radiation Oncology at the School of Medicine saw more than 1,500 cancer patients in their brachytherapy treatment rooms where implanted or injected radiation sources are used to treat cancer. That number was up five-fold from the fairly steady numbers of the late 1970s to the mid-1990s.

Because of the rapid growth of brachytherapy services at the School of Medicine, the department has created the Brachytherapy and micro-RT Treatment Center to ensure continued high-quality care and to implement new technologies. Department head Simon N. Powell, M.D., and Clinical Director Jeff M. Michalski, M.D., announced the appointment of Perry W. Grigsby, M.D., professor of radiation oncology, as the center’s director.

Perry Grigsby
Perry Grigsby

“Brachytherapy” means short-distance treatment and involves the application of radiation to cancerous tumors using internally placed radiation sources instead of an external radiation beam. The technique can achieve higher and more accurately targeted doses of radiation, which can more selectively destroy growing cancer cells.

Grigsby will monitor the expansion and update of the brachytherapy facility as well as oversee its staff of technologists, nurses, physicists, dosimetrists and researchers. The center will purchase two new brachytherapy systems and enlarge its physical space.

In addition, the facility will house a newly developed device called micro-RT, patented by Grigsby and colleague Daniel Low, Ph.D., associate professor of radiation oncology. The device allows researchers to irradiate tiny tumors in laboratory animals without exposing the rest of the animal to radiation. With micro-RT, scientists can study the effect of radiation treatment on individual tumors in experimental animals to help improve the treatment of human patients.

“Physicians are always finding new ways, new avenues, new applications — better ways to treat patients,” said Grigsby, who is a radiation oncologist with the Siteman Cancer Center. “The potential for brachytherapy is exciting.”

Many brachytherapy procedures at the School of Medicine rely on catheters to deliver tiny pellets of radioactive iridium directly to the tumor site. Computers control the time each pellet spends in the tumor — a matter of just minutes — to deliver a precise and uniform dose of strong radiation throughout the tumor.

The pellets are then drawn back into their storage chamber, leaving the patient free of any residual radiation.

“Brachytherapy has become the mainstay of therapy for gynecological cancers,” Grigsby said. “Part of our growth has come through patient referrals for these treatments — as advances have been made in the equipment, smaller hospitals haven’t had the patient base to upgrade to the more expensive technology. So, they began sending many patients to us.”

Also adding to the facility’s usage is the expansion of brachytherapy to other types of tumors. Using the technique for breast cancer patients has become more popular as studies have shown good results for very early stage tumors.

Imran Zoberi, M.D., instructor in radiation oncology, performs this procedure in the facility. Patients receive two brachytherapy treatments a day for five days, instead of the more typical once-daily external radiation treatment for 6-7 weeks.

Grigsby and his team also work with J. William Harbour, M.D., associate professor of ophthalmology, to treat ocular melanoma with brachytherapy that uses cup-shaped devices to destroy the tumor while saving the patient’s eye.

“We count ingested and injected radioisotopes as brachytherapy, too,” Grigsby said. “The School of Medicine has built a tremendous service center for thyroid cancer. Most of those patients will receive radioactive iodine as a post-surgery treatment, and we do that here in radiation oncology, which has again added to our patient base.”

Other radioisotopes are administered intravenously for lymphomas, liver metastases and brain tumors.

Grigsby is studying ways to use PET scans to fine-tune brachytherapy in gynecological cancer treatment.

“In a recent study, we showed that using PET scans let us better control placement of the brachytherapy catheters and determine tumor response over the course of treatment,” Grigsby said. “In most cervical cancer patients, PET scans show us that the tumor shrinks in an orderly way, allowing us to lower the radiation dose to cause fewer complications and side effects. If we don’t see the expected shrinkage, we change our treatment plan to get a better result.”