Intraoperative radiation therapy is an experimental way to give radiation therapy. During surgery to remove the breast cancer, the radiation is given as a single dose directly to the area where the cancer used to be.
This study, called the TARGIT study, shows that intraoperative radiation therapy and traditional external beam radiation had similar results 4 years after surgery. The results were presented at the 2010 American Society of Clinical Oncology (ASCO) annual meeting.
All 2,000 women in the TARGIT study were 45 or older and diagnosed with early-stage breast cancer. All the women had lumpectomy to remove the cancer.
Half the women were treated with one dose of intraoperative radiation therapy during surgery after the cancer was removed.
The other half were treated with traditional external beam radiation therapy. Traditional external beam radiation aims radiation at the whole breast or to the area of the breast where the cancer was. The source of the radiation is outside the breast, which is why it's called "external beam."
Many studies have shown the short- and long-term effectiveness of traditional radiation therapy. The drawbacks of traditional radiation therapy include daily trips to the hospital or cancer center to get treated -- typically 5 days a week for 4 to 6 weeks. Maintaining this schedule can be difficult for some women. Traditional radiation therapy also may expose healthy tissue, such as the heart and lungs, to radiation. These drawbacks make intraoperative radiation therapy attractive if it's proven to be just as effective and safe as traditional radiation therapy.
After 4 years of follow-up, the researchers found that both radiation techniques were equally effective at reducing the risk of the cancer coming back in the breast area and equally safe:
Radiation therapy is given after lumpectomy specifically to reduce the risk of the cancer coming back in the breast area.
While both approaches were equally safe, each treatment caused somewhat different side effects:
A seroma is a build-up of fluid at the site of surgery that may require more than one procedure to drain.
These results suggest that intraoperative radiation therapy may be a good alternative to traditional external beam radiation therapy. Still, more research with longer follow-up time is needed before doctors can confidently recommend intraoperative radiation therapy.
There are other alternatives to traditional external beam radiation therapy that deliver more focused radiation therapy over a shorter period of time that are already approved by the U.S. Food and Drug Administration to treat breast cancer, including:
You can learn more about radiation therapy options in the Breastcancer.org Radiation Therapy section.
CHICAGO (MedPage Today) -- For many breast cancer patients, a single dose of radiation -- delivered at the same time as surgery -- may work as well as several weeks of external beam radiation, researchers said.
In a large randomized trial, the process -- dubbed targeted intraoperative radiotherapy, or TARGIT -- was noninferior to standard radiation therapy after four years of follow-up, according to Jayant Vaidya, PhD, of University College London, and colleagues.
The frequency of major complications and toxicity was similar between the two approaches, Vaidya and colleagues reported online in The Lancet, in an article released to coincide with a presentation at the American Society of Clinical Oncology meeting here.
The results foreshadow a day when some breast cancer patients might complete all local treatment, surgical excision, sentinel lymph node biopsy, and radiotherapy in "one or two visits, without having to stay overnight in a hospital bed," the researchers concluded.
The TARGIT approach uses a device that provides a point source of low energy x-rays positioned in the tumor bed for between 20 and 35 minutes to irradiate tissues that are at highest risk of local recurrence, the researchers said.
It's one of several approaches to what is called accelerated partial-breast irradiation being developed to overcome some of the disadvantages of the standard course of external beam radiation, which takes weeks and requires several hospital visits.
The results from this trial need to be supported by longer follow-up, according to David Azria, MD, PhD, of INSERM U896 in Montpellier, France, and Céline Bourgier, MD, of Institut Gustave Roussy in Villejuif, France.
But, they wrote in an accompanying commentary, "in elderly patients, we are already convinced that accelerated partial-breast irradiation is the new standard and intraoperative radiotherapy an excellent approach."
Among other things, the trial refutes a long-standing criticism that the relatively low dose of radiation would be insufficient and would lead to an increased rate of local recurrence, Azria and Bourgier noted. On the other hand, they wrote, it is still not clear which patients should be selected for the approach.
The researchers enrolled more than 2,000 women ages 45 or older with early stage invasive ductal breast carcinoma who were undergoing breast-conserving surgery and randomized them to TARGIT or whole breast external beam radiotherapy.
The goal of the study was to demonstrate that the efficacy of the TARGIT approach was not inferior to the standard therapy, with a preset noninferiority margin of 2.5%, Vaidya and colleagues noted.
After four years of follow-up, there were six local recurrences in the TARGIT group and five in the external beam group, the researchers said.
Those numbers yielded a Kaplan-Meier estimate of local recurrence in the conserved breast of 1.20% for TARGIT and 0.95% for external beam radiotherapy, they said, with a difference between groups of 0.25% that met the preset noninferiority margin.
While the overall frequency of complications and toxicities was similar between the groups, there were significant differences in specific adverse events, the researchers said.
Wound seroma needing more than three aspirations were more frequent in the TARGIT group -- at 2.1% versus 0.8%, a difference that was significant at P=0.012.
On the other hand, a Radiation Therapy Oncology Group score of 3 or 4 was more frequent in the external beam radiotherapy group -- at 2.1% versus 0.5%, a difference that was significant at P=0.002.
The study was supported by the University College London Hospitals Comprehensive Biomedical Research Centre, the University College London Hospitals Charities, the National Institute for Health Research Health Technology Assessment programme, the National Health and Medical Research Council, and the German Federal Ministry of Education and Research.
Vaidya reported financial links with Photoelectron and from Carl Zeiss, the manufacturer of the device under study.
The Comment authors said they had no potential conflicts.
Primary source: The Lancet Source reference: Vaidya JS, et al "Targeted intraoperative radiotherapy versus whole breast radiotherapy for breast cancer (TARGIT-A trial): an international, prospective, randomised, non-inferiority phase 3 trial" Lancet 2010; DOI:10.1016/S0140-6736(10)60837-9.Additional source: The LancetSource reference: Azria D, Bourgier C "Partial breast irradiation: new standard for selected patients." Lancet 2010; DOI:10.1016/S0140-6736(10)60898-7. 6736(10)60898-7.
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