Prone whole-breast irradiation using three-dimensional conformal radiotherapy in women undergoing breast conservation for early disease yields high rates of excellent to good cosmetic outcomes in patients with large and/or pendulous breasts.
OBJECTIVE
To report our institution's experience using prone positioning for three-dimensional conformal radiotherapy (3D-CRT) to deliver post-lumpectomy whole breast irradiation (WBI) in a cohort of women with large and/or pendulous breasts, to determine the rate of acute and late toxicities and, more specifically, cosmetic outcomes. We hypothesized that using 3D-CRT for WBI in the prone position would reduce or eliminate patient and breast size as negative prognostic indicators for toxicities associated with WBI.


METHODS
From 1998 to 2006, 110 cases were treated with prone WBI using 3D-CRT. The lumpectomy, breast target volumes, heart, and lung were contoured on all computed tomography scans. A dose of 45-50 Gy was prescribed to the breast volume using standard fractionation schemes. The planning goals were ≥95% of prescription to 95% of the breast volume, and 100% of boost dose to 95% of lumpectomy planning target volume. Toxicities and cosmesis were prospectively scored using the Common Terminology Criteria for Adverse Effects Version 3.0 and the Harvard Scale. The median follow-up was 40 months.


RESULTS
The median body mass index (BMI) was 33.6 kg/m(2), and median breast volume was 1396 cm(3). The worst toxicity encountered during radiation was Grade 3 dermatitis in 5% of our patient population. Moist desquamation occurred in 16% of patients, with only 2% of patients with moist desquamation outside the inframammary/axillary folds. Eleven percent of patients had Grade ≥2 late toxicities, including Grade 3 induration/fibrosis in 2%. Excellent to good cosmesis was achieved in 89%. Higher BMI was associated with moist desquamation and breast pain, but BMI and breast volume did not impact fibrosis or excellent to good cosmesis.


CONCLUSIONS
In patients with higher BMI and/or large-pendulous breasts, delivering prone WBI using 3D-CRT results in favorable toxicity profiles and high excellent to good cosmesis rates. Higher BMI was associated with moist desquamation, but prone positioning removed BMI and breast size as factors for poorer cosmetic outcomes. This series adds to the growing literature demonstrating that prone WBI may be advantageous in select patients.
Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Carmen
C
Bergom
Tracy
T
Kelly
Natalya
N
Morrow
J Frank
JF
Wilson
Alonzo
A
Walker
Qun
Q
Xiang
Kwang Woo
KW
Ahn
Julia
J
White
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy / Q000379:methods; D004954:Esthetics; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D009929:Organ Size; D058958:Organs at Risk / Q000000981:diagnostic imaging; D056888:Patient Positioning / Q000379:methods*; D016684:Prone Position; D011832:Radiation Injuries / Q000473:pathology; D011859:Radiography; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D047368:Tumor Burden