Running the Numbers
New Institute Brings Proton Therapy to the Southeast Coast
Long-Term Outcomes Study Shows IMRT Curative of Prostate Cancer

Running the Numbers

5 of 6 patients with metastasis from ovarian cancer who were treated with percutaneous radiofrequency ablation (RFA) found that “after a single session, RFA resulted in complete necrosis,” according to Debra A. Gervais, MD, assistant professor of radiology at Harvard Medical School and director of interventional radiology at Massachusetts General Hospital (Boston). Gervais was lead author of a study published in the September issue of the American Journal of Roentgenology 1 that consisted of six patients with advanced ovarian cancer. The patients were treated with percutaneous RFA—which uses a high-frequency electric current to kill tumor cells—instead of repeated open surgical resection. “We followed the patients for between 8 months and 3.3 years,” Gervais said in a press release. “Treatment of ovarian cancer required multimodality approaches, including surgery and chemotherapy, but our study indicates that a small number of patients may benefit from RFA instead of repeated surgery.”

Reference

  1. Gervais DA, Arellano RS, Mueller PR. Percutaneous radiofrequency ablation of ovarian cancer metastasis to the liver: indications, outcomes, and role in patient management. AJR Amer J Roentgen. 2006;187:746?750. Available at: www.ajronline.org/cgi/content/abstract/187/3/746. Accessed November 9, 2006.

New Institute Brings Proton Therapy to the Southeast Coast

By Dana Hinesly

For decades, scientists have known that proton therapy—a form of radiation therapy that uses protons as opposed to photons or electrons—provides an extremely targeted method for treating cancers. Protons have unique physical characteristics that make it possible for the majority of their energy to be deposited right at the lesion while sparing a majority of the surrounding tissue. However, the technology’s exactitude has prevented it from being widely employed.

Before treating a patient with any type of radiation, identifying the exact size, shape, and depth of a tumor is imperative. Without a well-defined target, it’s impossible to take advantage of what protons can do.

“It was the improvements in diagnostic imaging—CT and MRI scanners—that allowed us to really take advantage of using the precision that protons offer,” says Stuart Klein, executive director of the University of Florida Proton Therapy Institute (UFPTI), Jacksonville, Fla. “You are able to deliver more of the radiation directly at the tumor site, while affecting less of the healthy tissue around it, and, as a result, you are able to reduce side effects as well as improve the local control rate.”

The UFPTI boasts two conventional linear accelerators and one cyclotron accelerator that is fed into four treatment rooms. The cyclotron accelerator is housed in a space with walls constructed from 181.5 feet of high-density concrete—the most radioactive area of the building—and weighs 440,000 pounds.

One of the four proton therapy rooms features a fixed beam, which restricts its use to eye treatments and research. Each of the remaining three was designed to accommodate massive gantries that allow clinicians to move the beam in a 360? radius, making it possible to execute a range of applications.

The opening of the 98,000-square-foot, $125 million Proton Therapy Institute comes 8 years after the initial proposal but only 3 years after construction began. Physicians began treating their first patient in August. Photos by Sarah Kiewel/University of Florida Health Science Center.

Standing three stories tall and weighing in at 200,000 pounds, each gantry features two robotic arms equipped with amorphous silicon panels. These x-ray panels are used prior to every treatment to identify exactly where the tumor is located in relation to bony structures or, in many cases, to aid clinicians in visualizing fiducial markers previously placed into the tumor.

In the few months since opening, UFPTI has ramped up its equipment, staff, and services slowly. “Of the four treatment rooms, we currently have only one in operation, and in that room, we only have a beam time approximately 6 hours per day,” Klein says. When not being applied to a patient, the beam is used to install and commission the rest of the system. The sole cyclotron accelerator works sequentially, sending a beam to one room at a time. “The majority of the time is actually spent setting up the patient in the right position,” he says. “The actual beam time is only 1 to 3 minutes per patient.”

The oncologists at UFPTI are focusing on pediatric cancers; head and neck cancers; as well as cancers of the brain, lung, and prostate. “There are some areas that conventional therapy does a wonderful job with, and you really can’t improve on the treatment,” Klein says. “We are concentrating on areas where we think the most benefit can be achieved, where we think that we can really take advantage of what proton therapy has to offer.”

An Elite Group

One of only five proton therapy centers in the country, UFPTI sits on the campus of Shands Jacksonville Hospital. The next-closest facilities are in Boston and Houston. The 98,000-square-foot, $125-million facility has about 12,000 square feet set aside for research space; and the centrally located Florida address puts the facility near a major interstate, an international airport, and the city’s port.

Alignment with the University of Florida’s nationally recognized radiation oncology department also was attractive. All of UFPTI’s faculty—currently consisting of six full-time radiation oncologists and about 35 ancillary staff members—are University of Florida personnel. As all four treatment rooms are brought online, that number is expected to grow to about 140 to 150 ancillary staffers and 30 to 40 clinicians, physicists, and researchers.

“We’re getting calls from all over the country, and we estimate that more than 50% of our patients will be coming from the southeast region outside the Jacksonville area,” Klein says. “When we are fully operational—which will take about 21?2 to 3 years—we should be able to treat close to 200 patients a day. We are proud to bring this level of expertise to our patients and their families.”

UFPTI is a nonprofit 501(c)3 organization. For more information, visit www.floridaproton.org.

Dana Hinesly is a contributing writer for  Medical Imaging. For more information, contact .

Long-Term Outcomes Study Shows IMRT Curative of Prostate Cancer

A long-term study conducted by researchers at Memorial Sloan-Kettering Cancer Center, New York City, showed that high-dose intensity-modulated radiation therapy (IMRT) was effective at eliminating prostate cancer over a follow-up period of 8 years. The report, which appeared in the October issue of the Journal of Urology,1 represents the first study of long-term outcomes for prostate cancer patients treated with IMRT.

Between April 1996 and January 2000, 561 men with prostate cancer were treated with IMRT targeting the prostate with a localized dose of intense radiation: 81 Gy. The patients were divided into three groups—favorable, intermediate, and unfavorable—by prognostic risk, according to the National Comprehensive Cancer Network’s guidelines. IMRT was curative for the majority of patients in all three groups: 89% of the favorable group were alive after 8 years, followed by 78% of the intermediate and 67% of the unfavorable. None of the survivors, whose median age was 68, showed evidence of disease at the end of the follow-up period, nor did any of the men develop secondary cancers as a result of the more intense radiation dose.

“These long-term results confirm our previous observations regarding the safety of high-dose intensity-modulated radiation therapy for clinically localized prostate cancer,” the study’s authors wrote. “Despite the application of high radiation doses, the incidence of rectal bleeding at 8 years was less than 2%. Despite the increased conformality of the dose distribution associated with intensity-modulated radiation therapy, excellent long-term tumor-control outcomes were achieved.”

The researchers reported that 1.6% of the patients developed rectal bleeding, and only 0.1% (3 patients) developed grade 3 rectal toxicity. No grade 4 rectal complications were reported, and the 8-year likelihoods of grade 2 and 3 urinary toxicities were 9% and 3%, respectively. Erectile dysfunction developed in 49% of patients who were potent before the IMRT treatment.

The authors also noted that dose levels of 78 Gy or higher are necessary to maximize the curative potential of IMRT; that distant metastases developed in 3%, or 17, of the patients; and that the addition of short-term androgen-deprivation therapy significantly increased the risk of erectile dysfunction in patients previously reporting the ability to maintain an erection sufficient for sexual intercourse.

“While there are currently no randomized trials comparing IMRT to 3D-CRT or to other more conventional forms of therapy,” the researchers concluded, “we believe the long-term data demonstrating efficacy and safety in this report substantiate the role of IMRT as a standard treatment intervention for patients with localized prostate cancer.”

—C. Vasko

Reference

  1. Zelefsky MJ, Chan H, Hunt M, Yamada Y, Shippy AM, Amols H. Long-term outcome of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer. J Urol. 2006;176:1415?1419. Available at: www.jurology.com/article/PIIS0022534706013711/abstract. Accessed November 8, 2006.