Shorter, and potentially cheaper, courses of radiation may soon be a real option for some women, according to new research presented at the annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO).

MammoSite: Promising Results from Large Trial

The MammoSite system, approved by the US Food and Drug Administration for the treatment of early stage breast cancer in 2002, delivers radiation from inside the space left after surgeons remove the breast tumor. Radiation is delivered through seed implants, which are planted inside a balloon that is placed inside the woman's breast. The radiation takes about 5-6 days to administer.

The technique is a type of intracavitary brachytherapy, and is one of several methods of accelerated partial breast irradiation, or ABPI.

In the study presented at ASTRO, researchers mined registry data to analyze breast cancer recurrence rates among 1440 women with early stage breast cancer who had been treated with MammoSite from May 2002 until September 2004. The researchers also looked at whether other factors, such as tumor location, type, size, and whether the cancer had spread to lymph nodes, affected results. Of the women who received treatment, the median age was 65.

After nearly 4 years, researchers saw low rates of breast cancer recurrence and rates of survival comparable with standard treatment.

"Not only does it make radiation treatment much more convenient, it may actually increase the rate of breast conservation, since some women choose mastectomy because they live too far from the radiation center and cannot afford the expense of 6 to 7 weeks of living or traveling to the center," said Peter Beitsch, MD, lead author of the study and a surgical oncologist at Medical City Dallas Hospital in Dallas.

"Also, there are many women who for a host of reasons don't receive the necessary postoperative radiation and the shortened course should hopefully allow more women to receive the therapy that they need."

While the results are encouraging, the research is still preliminary and has yet to be published in a major medical journal. Longer-term studies are also needed to be certain the MammoSite technique is equally effective as traditional radiation methods at preventing breast cancer recurrence. A 10-year clinical trial to investigate that was launched in 2005. (See "Study to Test Partial Breast Radiation.")

And since the device involves inserting a balloon into the breast, research is needed to further investigate the cosmetic impact of the procedure.

Shorter Radiation Cycles

The second study looked at whether an accelerated 3-week schedule of whole-breast radiation therapy (known as hypofractioned whole breast irradiation) was just as effective as the conventional 5-week schedule. Between 1993 and 1996, 1234 women were randomly assigned to receive whole breast radiation over 22 days (622 women) or 35 days (612 women). The women were followed for 12 years.

The researchers found the risk for recurrence at 10 years was just about the same for both groups: the risk was 6.2% for the group with the accelerated pace and 6.7% for the 35 day-group. At 10 years, 70% of the women in the accelerated radiation group had good cosmetic results, compared to 71% in the other group.

"There has been renewed interest in hypofractioned whole breast irradiation, due to potential radiation advantages, patient convenience, quality of life, and lower costs. However, long-term effects were a potential concern," said Timothy Whelan, MD, lead author of the study and a radiation oncologist at the Juravinski Cancer Centre at McMaster University in Hamilton, Ontario, Canada, where the research took place. "We were surprised that the risk of local recurrence and side effects was so low even at 12 years. Our study shows that this treatment should be offered to select women treated with early-stage breast cancer."

While these studies are promising, many doctors still consider both treatments experimental. Women who are interested in these options should talk to their doctors and consider participating in clinical trials. To find a clinical trial, see the American Cancer Society's online Clinical Trial Matching Service.

"Long-term Results of a Randomized Trial of Accelerated Hypofractionated Whole Breast Irradiation Following Breast Conserving Surgery in Women with Node-Negative Breast Cancer." First Author: T.G. Whelan. International Journal of Radiation Oncology, Biology, Physics. Abstract No. 60. Volume 72, Number 1, Supplement, 2008.

"Recurrence and Survival in the American Society of Breast Surgeons (ASBS) MammoSite^® RTS Registry Trial." First Author: P.D. Beitsch. International Journal of Radiation Oncology, Biology, Physics. Abstract No. 5. Volume 72, Number 1, Supplement, 2008.