A multi-institutional study of feasibility, implementation, and early clinical results with noninvasive breast brachytherapy for tumor bed boost.
OBJECTIVE
To evaluate the feasibility, implementation, and early results of noninvasive breast brachytherapy (NIBB) for tumor bed boost with whole breast radiation therapy (WBRT).


METHODS
NIBB is a commercially available (AccuBoost, Billerica, MA) mammography-based, brachytherapy system in which the treatment applicators are centered on the planning target volume (PTV) to direct (192)Ir emissions along orthogonal axes. A privacy-encrypted online data registry collected information from 8 independent academic and community-based institutions. Data were from 146 consecutive women with early-stage breast cancer after lumpectomy and WBRT receiving boost with NIBB between July 2007 and March 2010. Toxicity and cosmesis were graded according to the Common Toxicity Criteria (v. 3.0) and the Harvard scale. Median follow-up was 6 months (1-39 months).


RESULTS
Grade 1-2 skin toxicity was observed in 64%, 48%, and 21% during the acute (1-3 weeks), intermediate (4-26 weeks), and late-intermediate (>26 weeks) periods. There was no Grade 4 toxicity. At 6 months, for the entire cohort, cosmesis was excellent/good in 62%/38%. The subset receiving NIBB before WBRT had cosmetic scores of 32% and 63%, whereas during WBRT, 58% and 37% were rated as excellent and good, respectively. Breast compression was scored as "uncomfortable" in 12%, 29%, and 59% when NIBB was delivered before, during, or after WBRT. For each patient, the fraction-to-fraction variability in PTV was low. Skin flash was associated with a higher proportion of excellent cosmesis (58% vs. 42%) relative to having the applicator all within breast tissue.


CONCLUSIONS
These data indicate that NIBB is feasible and can be consistently implemented in a broad array of practice settings. Preliminary evaluation suggests that NIBB is associated with acceptably mild normal tissue toxicity and favorable early cosmesis. The application of NIBB before WBRT may be associated with better patient tolerance at the expense of less favorable cosmetic outcome.
Department of Radiation Oncology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA. shamid@tuftsmedicalcenter.org
Subarna
S
Hamid
Kathy
K
Rocchio
Douglas
D
Arthur
Robyn
R
Vera
Sandra
S
Sha
Michele
M
Jolly
Sean
S
Cavanaugh
Eric
E
Wooten
Rashmi
R
Benda
Brad
B
Greenfield
Bradley
B
Prestidge
Scot
S
Ackerman
Robert
R
Kuske
Coral
C
Quiet
Margaret
M
Snyder
David E
DE
Wazer
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D001940:Breast / Q000528:radiation effects; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002278:Carcinoma in Situ / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009367:Neoplasm Staging; D011832:Radiation Injuries / Q000473:pathology; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects / Q000379:methods; D012867:Skin / Q000528:radiation effects; D016896:Treatment Outcome
D007496:Iridium Radioisotopes