(PHILADELPHIA) Incontinence and impotence are two major complications feared by men undergoing treatment for prostate cancer, since the bladder and the rectum are the two organs adjacent to the prostate.
These organs are often in the line of fire when the radiation beams target the cancerous prostate. Now, with a highly sophisticated technology called Intensity Modulated Radiation Therapy or IMRT patients are experiencing fewer side effects than with conventional and even 3-dimensional conformal radiation therapy.
Fox Chase Cancer Center is the only institution in the Delaware Valley currently treating prostate cancer patients regularly with IMRT, which enables radiation oncologists to administer powerful doses of radiation with extremely high precision to the targeted prostate while sparing surrounding healthy organs.
“This new technology called IMRT is a significant advance and is our standard treatment for patients with prostate cancer,” says Allan Pollack, MD, PhD, chairman of the radiation oncology department at Fox Chase Cancer Center. “We use IMRT throughout the entire course of the patient’s treatment whereas some institutions only use IMRT at the very end, as a ‘boost’ treatment,” he says.
Conventional radiotherapy delivers only single beams of radiation with a uniform dose. A more advanced approach called 3-Dimensional Conformal Radiation Therapy or (3-DCRT), was the first in a new generation of treatment where the beam conformed to the irregular shape and size of an individual person’s prostate. Pollack says, “Radiation therapy is evolving quickly and Fox Chase continues to be a leader in this field. While we have shown that 3-DCRT was very effective, IMRT is even better.”
Like 3-DCRT, IMRT has conformal capability, but IMRT allows the radiation beams to vary in intensity. IMRT delivers between 60 to 100 pencil-thin beams that direct radiation at varying rates of intensity and can be maximized where the tumor is thickest and minimized when it is near healthy tissue.
“Tumors are not perfectly round. They come in all sizes, shapes, thickness and sometimes intertwine with organs,” says Eric Horwitz, MD, radiation oncologist at Fox Chase Cancer Center. “We precisely calibrate the computers and equipment so that we reach the target with minimal interference to other organs and the IMRT technology makes that possible.”
A crucial component of IMRT is the multi-leaf collimator, a specially designed attachment built into the front of the linear accelerator (the radiation treatment machine), which is equipped with metal “leaves” or “fingers” that mold the beams to conform to the 3-dimensional shape of a prostate. These leaves move during delivery of the beam in order to customize the radiation dosage to different areas of the tumor.
New studies presented at the American Society of Therapeutic Radiation (ASTRO) meeting this past November have shown that patients experienced fewer side effects when treated with IMRT than with 3-DCRT.
Fox Chase uses a multi-modality approach to ensure that the prostate is adequately centered in the treatment field. A foam mold or cast is made of the patient’s lower trunk or “seat” area. The mold hardens and helps to immobilize the patient each day for treatment. CT scans and MRI images are taken and fused together to further pin-point the target.
Fox Chase Cancer Center was the first and continues to be the only facility in the country to use a dedicated MRI-Simulator, located in the Radiation Department, in treatment planning for all of the prostate cancer patients. In addition to CT and MRI, physicians at Fox Chase use an advanced ultrasound system called the BAT® manufactured by Novus Corp, in Pittsburgh. The ultrasound system is similar to what is used to monitor a fetus during pregnancy and is used every day during the radiation treatment. “We use multiple tools each day of treatment in order to locate the prostate and spare any healthy surrounding tiss! ue undo exposure to radiation. And as the radiation technology is becoming more and more sophisticated, we are able to achieve that goal,” says Pollack.
Fox Chase Cancer Center, one of the nation's first comprehensive cancer centers designated by the National Cancer Institute in 1974, conducts basic and clinical research; programs of prevention, detection and treatment of cancer; and community outreach. For more information about Fox Chase activities, visit the Center's web site at http://www.fccc.edu or call 1-888-FOX CHASE.