New York City, NY (October 29, 2007) -- New advancements in a radiation oncology treatment called IMRT (intensity modulated radiation therapy) are proving far superior to standard radiation procedures used today in safeguarding the healthy tissues surrounding cancerous tumors, and thus improving patient care. That according to recent studies by researchers at Montefiore Medical Center who will present their findings at the annual meeting of the American Society for Therapeutic Radiology & Oncology (ASTRO), from Oct. 28 - Nov. 1, 2007.
"We compared treatment techniques for cancers of the lung, abdomen, pelvis and head and neck and were able to quantify just how much better IMRT was for patients in the studies than conventional radiation therapy," said Shalom Kalnicki, MD, chairman of the Department of Radiation Oncology at Montefiore.
IMRT technology allows oncologists to deliver thousands of precisely focused small x-ray beams of radiation that follow the exact contours of a cancerous tumor. Today's standard therapy, called 3-D conformal radiation therapy (CRT), uses large crossfiring x-ray beams and is not as accurate. What is exciting about these studies is that researchers are now beginning to quantify how much more precise IMRT is, especially with recent advancements produced by new software technology.
In a study of patients with lung cancer (Madhur Garg, et al "Effect of IMRT on Dose Sparing of Normal Lung and Esophagus for External Beam Gated Treatment for Lung Cancer"), the researchers found the average dose of radiation was reduced by 20 percent to the esophagus and by 30 percent to the area of the lung most critical for breathing. "By developing and carrying out a tailor-made IMRT treatment plan for each patient, we reduced significantly the chance of having radiation beams harm healthy lung tissue and therefore the potential for impaired breathing," said Dr. Kalnicki.
In this study, researchers used an advanced form of IMRT, which modifies radiation dosage to accommodate changes in the shape of the lung as the patient breathes. The software advancements making this possible are called 4-dimensional planning (which uses a CT scan movie to ascertain cycles of breathing) and respiration gated treatment delivery (which matches radiation delivery to the breathing cycles). For patients with esophageal cancer in the study, the effective radiation dose, and potential adverse effect on healthy tissue, was reduced 20 percent.
In a second study (Jill Rossinow, et al, "IMRT With Respiratory Gating Provides Superior Renal and Bowel Sparing in Upper Abdominal Tumors"), Montefiore researchers used IMRT to treat patients with pancreatic cancer, and radiation dosage to the nearby kidneys was reduced by 38 percent. In the same study, dose to the normal bowel was reduced by 38 percent.
In a third study (Peter Ahn, et al, " Adaptive IMRT Planning in Head and Neck Cancers"), Montefiore Medical Center - Albert Einstein College of Medicine researchers reported groundbreaking data on the use of image guided adoptive planning, another advanced form of IMRT, to treat complex-shaped head and neck cancers. In image guided adoptive planning, the beam dosage is changed as the tumor shrinks and changes shape after each of several treatments. Sparing of the salivary glands, mandible, nerves and oral cavity lining was dramatically increased by using this method, resulting in significant improvement of patient quality of life. These patients were simultaneously being treated with chemotherapy.