In vivo intraoperative radiotherapy: a novel approach to radiotherapy for early stage breast cancer.
BACKGROUND
Intraoperative radiotherapy (IORT) has the potential to eliminate the access problems associated with standard 6-week post-operative external beam radiotherapy for patients with breast cancer. However, accurate delivery of the IORT dose for breast cancer has been problematic due to difficulty estimating the tumor bed after tumor removal and tissue re-approximation. We are investigating the feasibility of partial breast irradiation using a single fraction of IORT delivered to the tumor in vivo prior to surgical resection.


METHODS
In a trial, approved by the University of North Carolina School of Medicine Institutional Review Board, patients > or =55 years old with infiltrating ductal carcinoma without an extensive intraductal component with an overall tumor size < or =3.0 cm receive a single dose of IORT in place of standard post-operative radiotherapy.


RESULTS
All patients undergo preoperative ultrasonography to define the target volume. In a standard operating room, the tumor is exposed through a standard partial mastectomy incision. IORT is then delivered using a mobile, self-shielded, magnetron-driven X-band linear accelerator (Intraop Corp, Santa Clara, CA, USA). 15 Gy is delivered to the 90% isodose line covering the tumor with a 1 cm margin anterior-posterior and 2 cm margins laterally. After IORT, partial mastectomy is performed in the usual manner.


CONCLUSIONS
IORT for breast cancer, delivered to the exposed tumor in vivo, is feasible and allows accurate estimation of the tumor bed. Further follow-up is ongoing to determine the efficacy of this approach.
Stitzenberg
Karyn B
KB
Department of Surgery, University of North Carolina, Chapel Hill, NC, USA. stitz@email.unc.edu
Klauber-Demore
Nancy
N
Chang
Xiao Sha
XS
Calvo
Benjamin F
BF
Ollila
David W
DW
Goyal
Lav K
LK
Meyers
Michael O
MO
Kim
Hong Jin
HJ
Tepper
Joel E
JE
Sartor
Carolyn I
CI
D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008197:Lymph Node Excision; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D016896:Treatment Outcome