Prone accelerated partial breast irradiation after breast-conserving surgery: preliminary clinical results and dose-volume histogram analysis.
OBJECTIVE
To report the clinical and dose-volume histogram results of the first 47 patients accrued to a protocol of accelerated partial breast irradiation. Patients were treated in the prone position with three-dimensional conformal radiotherapy after breast-conserving surgery.


METHODS
Postmenopausal women with Stage T1N0 breast cancer were eligible only after they had first refused to undergo 6 weeks of standard radiotherapy. Planning CT in the prone position was performed on a dedicated table. The postoperative cavity was defined as the clinical target volume, with a 1.5-cm margin added to determine the planning target volume. A total dose of 30 Gy at 6 Gy/fraction was delivered in five fractions within 10 days.


RESULTS
The median age of the patients was 67.5 years (range, 51-88 years). The median tumor diameter was 9 mm (range, 1.3-19 mm). In all patients, the prescribed dose encompassed the planning target volume. The mean volume of the ipsilateral breast receiving 100% of the prescription dose was 26% (range, 10-45%), and the mean volume contained within the 50% isodose surface was 47% (range, 23-75%). The lung and heart were spared by treating in the prone position. Acute toxicity was modest, limited mainly to Grade 1-2 erythema. With a median follow-up of 18 months, only Grade 1 late toxicity occurred, and no patient developed local recurrence.


CONCLUSIONS
These data suggest that this approach is well tolerated, with only mild acute side effects and sparing of the heart and lung.
Formenti
Silvia C
SC
Department of Radiation Oncology, New York University School of Medicine, New York, New York, USA. silvia.formenti@med.nyu.edu
Truong
Minh Tam
MT
Goldberg
Judith D
JD
Mukhi
Vandana
V
Rosenstein
Barry
B
Roses
Daniel
D
Shapiro
Richard
R
Guth
Amber
A
Dewyngaert
J Keith
JK
D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008875:Middle Aged; D016684:Prone Position; D011832:Radiation Injuries / Q000473:pathology; D011859:Radiography; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000379:methods*