Advancements in radiation therapy for early-stage breast cancer
Radiation has long been used with surgery for local control of early-stage breast cancer. Research has shown that, in most cases, women who have a lumpectomy with whole breast radiation have the same low risk of local recurrence as those who have a mastectomy. Now, radiation is also being recommended after mastectomy for some women with high-risk tumors.
A number of trials are exploring new ways to deliver radiation in a shorter time as well as ways to help radiation pack more of a punch. Here are some of the techniques being studied:
> Boost radiation: provides an additional, focused course of radiation, usually for one week, in the area where the tumor was removed after five weeks of whole-breast radiation is complete. The trade-off may be a little more fibrosis, or scarring and hardening, of the breast tissue in a small percentage of patients.
> Radiosensitization: occurs when a drug is used to make the tumor more vulnerable to radiation therapy. Preclinical research on the drug Herceptin (trastuzumab) appears to make tumor cells that overproduce the HER2 oncogene more sensitive to radiation. Other drugs such as the chemotherapy drug Xeloda (capecitabine) and biological drugs called PARP inhibitors are being investigated in this setting.
> Accelerated whole breast radiation: (also known as hypofractionated radiation therapy) shortens radiation from five or six weeks to three or four, with slightly higher doses of radiation. This option is attractive for those who must travel long distances for treatment.
> Partial breast radiation: focuses radiation in the specific area where a tumor was removed.
> Brachytherapy: involves implanting radioactive seeds directly into the breast in the area of the tumor either in a balloon (MammoSite) or through a series of catheters (interstitial). In both options, the radioactive seeds are removed at the end of treatment, but the balloon or catheters stay in place until 10 treatments over a period of five days are complete.
> Targeted intraoperative radiation therapy: (TARGIT) refers to radiation that occurs at the time of the lumpectomy, allowing a woman to awaken from surgery having finished radiation. A study presented at the 2010 American Society of Clinical Oncology annual meeting offered results of a 10-year clinical trial that found that this single-dose intraoperative radiation treatment was safe and effective and would save the patient time and money. Some experts are concerned, however, about the cost and availability of the specialized radiation equipment in the operating room, the reduced radiation received by the women, and the lack of long-term follow-up.
Women considering possible radiation delivery options should discuss with their surgeon and radiation oncologist the type of radiation being recommended. They should ask what kind of factors are used to select appropriate candidates and about the risk of long-term or late effects.