April 21, 2013
IMRT Reduces Side Effects Of Breast Cancer Treatments
redOrbit Staff & Wire Reports - Your Universe Online
Treating early breast cancer patients with an advanced form of radiotherapy known as IMRT could reduce the side effects those women experience, according to the results of a randomized trial presented Sunday during the 2nd Forum of the European Society for Radiotherapy and Oncology (ESTRO) in Geneva, Switzerland.IMRT (intensity modulated radiotherapy) is a high-precision form of treatment that delivers an even dose of radiation, the researchers said. Thus, when compared to standard two-dimensional radiotherapy (2DRT), IMRT can reduce the cosmetic issues that often occur following breast radiotherapy.
A team of UK researchers analyzed the radiotherapy treatment plans of more than 1,100 patients with early breast cancer. Each of those patients had previously undergone breast-conserving surgery, and their plans were screened to see if they would have received an uneven dose of radiation with standard 2DRT treatment.
“We believe that this study, the largest prospective trial in the world to test breast IMRT against standard two-dimensional radiotherapy, will be practice-changing at an international level,” Dr. Charlottes Coles, a consultant clinical oncologist at Addenbrooke's Hospital Oncology Centre, Cambridge, UK, said in a statement. “Analyzing the results five years after treatment, we saw significant benefits in patients who had received IMRT.”
Seventy-one percent of the treatment plans fell into that category, according to the researchers, and those patients were then randomly assigned to receive either 2DRT or IMRT. The remaining 29 percent of the patients were treated using the traditional radiotherapy method, but were still contacted for follow-up during the trial.
They also emphasized the importance of treating the target using correct and evenly-distributed doses with external radiotherapy. According to the researchers, the goal is to treat the entire breast with between 95 percent and 107 percent of the prescribed dose, as too low a dose could lead to a recurrence of the tumor and too much radiation can lead to side-effects such as skin changes.
“The problem with 2D breast radiotherapy is that the dose distribution is only recorded across the central part of the breast,” explained Dr. Coles. “Usually it meets the 95-107percent constraints, but the shape of the breast changes, so if the same plan is looked at in 3D, then there may well be areas with overly high doses. By modulating the intensity of the radiation beam, IMRT can be used to correct for this and smooth out the dose.”
She and her colleagues set out to determine whether or not the patients that would have received a dose of more than 107 percent to parts of their breast with 2DRT would receive clinical benefit from using IMRT.
Planning for the advanced procedure uses scan results to determine what dose intensity will best treat the tumor, making it more complex and time-consuming than 2DRT planning and thus underscoring the need to demonstrate a patient will clearly benefit from the procedure versus traditional radiotherapy.
“We saw that fewer patients in the IMRT group developed skin telangiectasia (dilated blood vessels near the surface of the skin), and the overall cosmetic effect in the breast was better,” Dr. Coles reported.
Additionally, there was said to be no significant difference between the 2DRT and IMRT groups in terms of breast shrinkage, breast edema, breast hardening, or pigmentation changes. The researchers plan to follow up by reviewing patient questionnaires to determine if the advanced form of radiotherapy improves their overall quality of life.
“Although IMRT is employed increasingly in breast cancer, its use is far from universal throughout the world. We hope that the evidence of benefit shown in our trial will encourage its greater use, resulting in improved patient access and, ultimately, improved outcomes for breast cancer patients,” said Dr Coles.
“This study not only shows a better outcome for the women treated with IMRT, but has an additional value in defining the selection criteria for providing treatment to those patients who will benefit from new frontline technologies,” said ESTRO President Vincenzo Valentini.
“In the study design, the patients who could be treated satisfactorily by standard technology were not referred for IMRT, avoiding the use of a complex technique where it was not necessary. At a time when resources are limited, individualized medicine can help us offer new technology only to those patients who will have a tangible benefit from it,” he added.