Studies Show Risks and Benefits of Intraoperative Radiation Therapy

Studies Show Risks and Benefits of Intraoperative Radiation Therapy

While two large studies suggest that intraoperative radiation therapy offers about the same overall survival and rates as whole-breast external beam radiation therapy for certain women diagnosed with early stage-breast cancer, there are concerns about local recurrence rates.
Dec 3, 2013.This article is archived
We archive older articles so you can still read about past studies that led to today's standard of care.
 
Intraoperative radiation therapy (sometimes abbreviated IORT) is a relatively new way to give radiation therapy. During surgery to remove breast cancer, radiation is given as a single dose directly to the area where the cancer used to be.
Two large studies suggest that intraoperative radiation therapy offers about the same overall survival rates as whole-breast external beam radiation therapy for certain women diagnosed with early-stage breast cancer. Still, women who had intraoperative radiation therapy had higher rates of local recurrence (cancer coming back in the same breast) than women who had whole-breast external beam radiation therapy.
Traditional whole-breast external beam radiation therapy aims radiation at the whole breast or to the area of the breast where the cancer was. The source of radiation is outside the breast, which is why it’s called “external beam.”
In the TARGIT-A study, more than 3,400 women ages 45 or older diagnosed with early-stage breast cancer were scheduled to have lumpectomy to remove the cancer. The women were randomly assigned to have either intraoperative radiation therapy or whole-breast external beam radiation therapy:
  • 1,721 women got intraoperative radiation therapy; 15.2% of these women had to have additional whole-breast external beam radiation therapy after surgery because their pathology report showed the cancer had more advanced characteristics than originally thought
  • 1,730 women got whole-breast external beam radiation therapy
About half of the women who got intraoperative radiation therapy got the radiation at the same time as lumpectomy. The other half got intraoperative radiation therapy after lumpectomy. To do this, the surgeon reopened the incision.
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 more radiation.
After about 5 years of follow-up, the researchers found that both radiation techniques had about the same breast cancer survival rates:
  • 97.4% for intraoperative radiation therapy
  • 98.1% for whole-breast external beam radiation therapy
Women who got intraoperative radiation therapy were more likely to have breast cancer come back in the same breast than women who got whole-breast external beam radiation. Women who got intraoperative radiation therapy had fewer skin side effects than women who got whole-breast external beam radiation.
The TARGIT-A study researchers believe that giving intraoperative radiation therapy at the same time as lumpectomy is a good option for certain women diagnosed with early-stage breast cancer. Still, more research needs to be done to figure out which women can safely receive intraoperative radiation therapy. Also, this study only had 5 years of follow-up data. Longer follow-up information also will help doctors decide who can safely get intraoperative radiation therapy.
In the ELIOT study, which was smaller than the TARGIT-A study, 1,305 women ages 48 to 75 diagnosed with early-stage breast cancer that was no larger than 2.5 cm were randomly assigned to get whole-breast external beam radiation therapy or intraoperative radiation therapy during lumpectomy:
  • 654 women got whole-breast external beam radiation
  • 651 women got intraoperative radiation therapy
After about 6 years of follow-up, the researchers found results that were similar to TARGIT-A results. Both groups had about the same breast cancer survival rates:
  • 96.8% in the intraoperative radiation therapy group
  • 96.9% in the whole-breast external bream radiation therapy group
Women who got intraoperative radiation therapy had fewer skin side effects compared to women who got whole-breast external beam radiation.
The ELIOT study also found that women who got intraoperative radiation therapy had higher rates of recurrence in the same breast. The researchers in the ELIOT study didn’t explain why this rate was higher in one group than the other.
While these two studies suggest that overall survival is similar in the short-term for intraoperative and whole-breast external beam radiation therapy, there are some concerns. The studies raise serious questions about how effective intraoperative radiation therapy is at reducing the risk of cancer coming back in the same breast.
More research needs to be done so doctors know exactly who can safely get intraoperative radiation therapy before they can confidently recommend it.
Doctors are studying 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:
  • two types of internal radiation therapy (brachytherapy)
    • multi-catheter internal radiation
    • balloon internal radiation (brand name: MammoSite)
  • 3-D conformal external beam radiation
You can learn more about radiation therapy options in the Breastcancer.org Radiation Therapy section.

— Last updated on July 31, 2022, 10:40 PM

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