Long-term clinical outcomes of whole-breast irradiation delivered in the prone position.
OBJECTIVE
The aim of this study was to evaluate retrospectively the effectiveness and toxicity of post-lumpectomy whole-breast radiation therapy delivered with prone positioning.


METHODS
Between September 1992 and August 2004, 245 women with 248 early-stage invasive or in situ breast cancers were treated using a prone breast board. Photon fields treated the whole breast to 46 to 50.4 Gy with standard fractionation. The target volume was clinically palpable breast tissue; no attempt was made to irradiate chest wall lymphatics. Tumor bed boosts were delivered in 85% of cases. Adjuvant chemotherapy and hormonal therapy were administered to 42% and 62% of patients, respectively.


RESULTS
After a median follow-up of 4.9 years, the 5 year actuarial true local and elsewhere ipsilateral breast tumor recurrence rates were 4.8% and 1.3%, respectively. The 5-year actuarial rates of regional nodal recurrence and distant metastases were 1.6% and 7.4%. Actuarial disease-free, disease-specific, and overall survival rates at 5 years were 89.4%, 97.3%, and 93%, respectively. Treatment breaks were required by 2.4% of patients. Grade 3 acute dermatitis and edema were each limited to 2% of patients. Only 4.9% of patients complained of acute chest wall discomfort. Chronic Grade 2 to 3 skin and subcutaneous tissue toxicities were reported in 4.4% and 13.7% of patients, respectively.


CONCLUSIONS
Prone position breast radiation results in similar long-term disease control with a favorable toxicity profile compared with standard supine tangents. The anatomic advantages of prone positioning may contribute to improving the therapeutic ratio of post-lumpectomy radiation by improving dose homogeneity and minimizing incidental cardiac and lung dose.
Stegman
Lauren D
LD
Department of Radiation Oncology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Beal
Katherine P
KP
Hunt
Margie A
MA
Fornier
Monica N
MN
McCormick
Beryl
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016684:Prone Position; D012189:Retrospective Studies; D016896:Treatment Outcome