Partial-breast irradiation can provide good cosmetic results.(Gynecology)

ATLANTA -- When partial-breast irradiation was delivered with the MammoSite balloon catheter system after lumpectomy, the majority of patients showed good to excellent cosmetic results and had no local recurrences of cancer at 2 years, according to the first analysis of MammoSite Registry Trial data, presented at a symposium that was sponsored by the Society of Surgical Oncology.

Partial-breast irradiation (PBI) offers women the convenience of shortening their course of radiation treatment from 6 weeks for standard whole-breast radiation to a week. It also has the potential to substantially improve the documented underutilization of breast-conserving therapy in the United States, Peter D. Beitsch, M.D., told this newspaper.

The trial enrolled 1,419 women to receive PBI instead of a mastectomy.

The best cosmetic results were seen in women with larger breasts or with at least 7 mm of breast tissue between the skin and the balloon catheter, which is inflated inside the lumpectomy cavity. The average skin spacing was 10 mm.

Less than 10% of the women who enrolled (139) could not be treated because of a lack of skin spacing, balloon failure, lack of cavity conformity, or positive nodes. PBI is contraindicated in patients who are very young or who are node positive.

Of the 1,280 women treated, only 1% had positive margins and 91% had tumor margins greater than 2 mm. About 80% of the women had T1 tumors, 6.3% had T2 tumors, and 13.3% had ductal carcinoma in situ.

Only 3% of the patients had positive lymph nodes. Two percent of patients had breast size A, compared with 20% B, 33% C, 23% D, and 22% not reported.