Accelerated Partial Radiation

Have you heard of accelerated partial radiation before?
Women who are diagnosed with early-stage breast cancer often choose to have the cancer removed by lumpectomy, and they usually have radiation therapy after surgery as well.   Radiation therapy after lumpectomy lowers the risk of the cancer recurring and it makes lumpectomy as effective as mastectomy.  Radiation can be delivered to the entire breast, whole-breast radiation, or to just the area of the breast where the cancer was located, partial-breast radiation.  Traditional whole-breast radiation typically lasts 5 days a week for 4 to 6 weeks; and the unintentional exposure of nearby healthy tissue (lungs or heart, for example) to is a factor to consider as well.
One of the newer ways to deliver radiation is accelerated partial-breast radiation.   This is a new technique that delivers a more focused and intense  therapy over a shorter period of time.
3-D conformal external beam radiation (3DCRT) is one type of accelerated partial-breast radiation.  3DCRT starts with a planning session.   A special MRI or CAT scan of the breast is done and is used to map out small treatment fields for the area at risk.  The type and distribution of radiation is designed to maximize the dose to the area that needs to be treated and avoid or minimize radiation to tissue near the area.  The radiation is delivered with a linear accelerator, the same machine used in traditional whole-breast radiation, twice a day for 1 week.
A study has found that women diagnosed with early-stage breast cancer and had 3DCRT after lumpectomy had worse cosmetic results than women who got traditional whole-breast radiation after lumpectomy.  The study was published online on July 8, 2013 by the Journal of Clinical Oncology.
In the RAPID trial, researchers randomly assigned 2,135 women diagnosed with either early-stage breast cancer or DCIS to get either 3DCRT (1,070 women) or whole-breast radiation (1,065 women) after lumpectomy.  Before they received any radiation therapy, all the women were assessed by a trained nurse using a cosmetic rating system for breast cancer.  After radiation therapy, the women were again assessed by a trained nurse at 2 weeks, 3 months, 6 months, 12 months, and then once a year.
The rating system compared the treated and untreated breast for:

• size and shape
• location of the nipple and areola
• how the surgical scar looked
• whether or not there was an enlargement of small blood vessels on the skin
• overall appearance of the breasts

The researchers then compared cosmetic results and side effects between the two types of radiation.
The researchers found that women who had 3DCRT had worse cosmetic results than women who had whole-breast radiation:

• Before radiation, 18.9% of women who would get 3DCRT had fair or poor cosmetic results compared to 17% of women who would get whole-breast radiation.
• Three years after radiation, 29% of women who had 3DCRT had fair or poor cosmetic results compared to 16.5% of women who got whole-breast radiation.
• Five years after radiation, 32.8% of women who had 3DCRT had fair or poor cosmetic results compared to 13.4% of women who got whole-breast radiation.

Looking at side effects, the researchers found that women who had 3DCRT were more likely to have telangiectasia and breast induration (hardening or thickening of the skin) than women who had whole-breast radiation.  About a quarter of the women in both groups had mild to moderate pain after radiation.  Very few women in either group had severe pain.
While other ongoing studies have suggested that accelerated partial-breast irradiation is safe, none of these other studies have reported on cosmetic results.  Since the cosmetic results and side effects were worse with 3DCRT than whole-breast radiation, the researchers recommended that 3DCRT not be routinely used unless it’s part of a clinical trial.  More research with long-term follow-up is needed so doctors know for sure that accelerated partial-breast irradiation is a good alternative to whole-breast radiation.
If you’ve been diagnosed with early-stage breast cancer and lumpectomy followed by radiation therapy will be part of your treatment, ask your doctor about the radiation therapy options that make the most sense for your unique situation, including:

• the characteristics of the cancer (size, location, lymph node involvement)
• your personal preferences
• the experience level and results of the doctors who will administer your radiation therapy