(RxWiki News) Radiation therapy is commonly given after breast cancer surgery. The intense energy kills remaining cancer cells. The therapy can also change the look, feel and size of the treated breast.
But one type of radiotherapy seems to have advantages.
High-precision radiation called intensity modulated radiotherapy (IMRT) can reduce the risks of cosmetic changes often experienced by early breast cancer survivors.
A recent randomized trial also found that the IMRT delivers more even doses of radiation throughout the breast than does conventional two-dimensional (2D) radiotherapy.
The authors suggest these findings may change the way early breast cancer is treated.
"Find out what type of radiation you’ll be receiving."
Charlotte Coles, MD, a clinical oncologist from Addenbrooke's Hospital Oncology Centre in Cambridge, United Kingdom, and colleagues compared the effects of 2D and IMRT.
Whole-breast radiation is tricky. The goal is to beam an even dose of radiation throughout the breast. Because of the contours of the breast, even distribution is difficult but essential.
Not enough radiation increases the risk that the tumor will return, while too much radiation can cause skin changes. So, as a rule, radiation oncologists aim to distribute within a range of 95-107 percent of the prescribed dosage.
IMRT addresses the dosing dilemma. “By modulating the intensity of the radiation beam, IMRT can be used to correct for this and smooth out the dose," Dr. Coles said in a news release.
Researchers evaluated the radiotherapy treatment plans of 1,145 patients with early (stage l, ll) breast cancer who had undergone a lumpectomy that removed only the tumor and preserved the rest of the breast.
After screening the radiotherapy plans, the researchers found that 71 percent delivered an uneven radiation dose. Patients in this group were then randomly assigned to receive either 2D radiotherapy (2DRT) or IMRT.
IMRT is more difficult and time-consuming to plan than is 2DRT. Imaging scans are used to determine the dose intensity.
The women were evaluated five years after their radiotherapy was completed.
Researchers found that IMRT was gentler on the breast and resulted in fewer cosmetic problems. Women who received the IMRT had fewer dilated blood vessels near the surface of the skin – a condition called skin telangiectasia – and a better overall physical appearance, the researchers discovered.
There was no significant difference among the groups in terms of breast shrinkage, edema, hardening or pigment changes – all common after-effects of radiotherapy.
Frank Vicini, MD, FACR, radiation oncologist at 21st Century Oncology in Royal Oak, MI, told dailyRx News, “The phase III trial by Coles et al provides the highest level of clinical evidence that breast IMRT can no longer be considered experimental or investigational.
"This excellent study (as well as other reported phase III trials) helps to further define patient selection criteria for breast IMRT and points out that it should be considered the standard of care for these patients and several other groups of women,” Dr. Vicini said.
Dr. Coles said, “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."
Findings from this study were presented at the 2nd Forum of the European Society for Radiotherapy and Oncology (ESTRO). No funding or conflicts of interest information was provided.
All research is considered preliminary before it is published in a peer-reviewed journal.
