Patterns of failure after MammoSite brachytherapy partial breast irradiation: a detailed analysis.
OBJECTIVE
To report the results of a detailed analysis of treatment failures after MammoSite breast brachytherapy for partial breast irradiation from our single-institution experience.


METHODS
Between October 14, 2002 and October 23, 2006, 78 patients with early-stage breast cancer were treated with breast-conserving surgery and accelerated partial breast irradiation using the MammoSite brachytherapy applicator. We identified five treatment failures in the 70 patients with >6 months' follow-up. Pathologic data, breast imaging, and radiation treatment plans were reviewed. For in-breast failures more than 2 cm away from the original surgical bed, the doses delivered to the areas of recurrence by partial breast irradiation were calculated.


RESULTS
At a median follow-up time of 26.1 months, five treatment failures were identified. There were three in-breast failures more than 2 cm away from the original surgical bed, one failure directly adjacent to the original surgical bed, and one failure in the axilla with synchronous distant metastases. The crude failure rate was 7.1% (5 of 70), and the crude local failure rate was 5.7% (4 of 70). Estimated progression-free survival at 48 months was 89.8% (standard error = 4.5%).


CONCLUSIONS
Our case series of 70 patients with >6 months' follow-up and a median follow-up of 26 months is the largest single-institution report to date with detailed failure analysis associated with MammoSite brachytherapy. Our failure data emphasize the importance of patient selection when offering partial breast irradiation.
Chen
Sea
S
Department of Radiation Oncology, Rush University Medical Center, Chicago, IL 60612, USA. sea_chen@rush.edu
Dickler
Adam
A
Kirk
Michael
M
Shah
Anand
A
Jokich
Peter
P
Solmos
Gene
G
Strauss
Jonathan
J
Dowlatshahi
Kambiz
K
Nguyen
Cam
C
Griem
Katherine
K
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002278:Carcinoma in Situ / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D018275:Carcinoma, Lobular / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D011859:Radiography; D011879:Radiotherapy Dosage; D017211:Treatment Failure