Intensity modulated radiation therapy (IMRT) is well on its way to becoming the new gold standard for treating cancer, especially head and neck and genitourinary tumors. The ability to shield noncancerous areas while sending higher doses of radiation allows for fewer negative side effects and better cure rates.
Arno Mundt, MD, professor and chairman of the radiation and oncology department at the University of California at San Diego has led several studies about the technology. In one, IMRT users were asked about their impressions of the technology and their rate of use for various conditions.
The first patient treated via IMRT was in 1992. Acquisition has been rapid, with 74 percent of the country using IMRT by 2004, according to Mundt’s use study. That’s a complete revolution, he says. “You don’t see a complete change in the field that quickly. We did things very similarly for over 100 years. There were improvements, but the basic approach was very static until IMRT. This is a very exciting time.”
Improving quality of life
Head, neck, and prostate cancers are the most common conditions treated with IMRT and the most likely to benefit from the ability to increase radiation to the tumor while protecting healthy tissue. IMRT has revolutionized treatment of head and neck cancer, says Charles H. Albrecht, MD, of Finger Lakes Radiation Oncology Center in Clifton Springs, N.Y., which began using IMRT in 2000. For these patients, radiation has a drastic quality-of-life effect on the carotid salivary glands. “In conventional radiation, the patient would get at least the same dose to the salivary glands if not a higher dose,” Albrecht says. They had to always carry a water bottle with them, and the lack of saliva has serious consequences — such as teeth falling out or rotting and terrible dry mouth. Now, few patients need a water bottle.
When treating with conventional radiation, the patient typically receives 300 rads a minute. That’s concentrated and over very quickly, Albrecht says. With IMRT, only 75 to 150 rads hit the patient, and the rest is absorbed into the equipment. “It takes longer to give the same dose of radiation, but we’re doing it more precisely.”
Despite these improvements, IMRT still is probably the scariest thing a patient will go through, says Albrecht. The mouth, larynx, and other elements exposed to even the lower dose of radiation become inflamed. “But coming out of it, recovery is faster and we’re able to spare more normal functions.”
Albrecht uses equipment from NOMOS Radiation Oncology, which is essentially an attachment to a standard linear accelerator. Albrecht “like[s] that you’re using a very mature technology producing radiation. The accelerator is basically technology introduced in the late 1950s that has matured and is very reliable.”
After a planning CT scan, Albrecht traces on the computer screen the carotid glands, submandibular glands, and all the lymph nodes and the tumor structure he wants to treat. This goes back to the physicist who comes up with a treatment plan that delivers the right dose to each structure. In the case of tonsil tumors, Albrecht can attack the tonsil and the lymph node under the jaw bone aggressively but send a different dose of radiation to other lymph nodes that may or may not be cancerous. “We are definitely increasing our chances of a cure,” he says. “I’ve been very impressed with it clinically.”
First timers blown away
There is little doubt that IMRT lives up to the great reviews. When Ironwood Cancer & Research Center in Chandler, Ariz., opened last October intending to offer state-of-the-art radiation and medical oncology services, says Brent Applegate, chief therapist, the facility installed IMRT equipment from Elekta.
The facility’s first IMRT patient had pancreatic cancer. Because of the anatomy of the pancreas and the organs around it, most people with pancreatic tumors don’t perform very well, Applegate says. It was difficult to give a high enough dose to treat the tumor without making them sick. “We gave her a fairly escalated dose, and she had little or no side effects, which is unheard of. We were blown away for our first experience out of the gate.” He says they kept waiting for the patient to get sick, but she came back, smiling, every day. “That really sold us on the technology,” Applegate says.
The good results kept coming. The facility’s staff was able to get patients through treatments for five to seven weeks without breaks. That results in