Fat necrosis after partial-breast irradiation with brachytherapy or electron irradiation versus standard whole-breast radiotherapy--4-year results of a randomized trial.
OBJECTIVE
To examine the incidence and clinical relevance of fat necrosis after accelerated partial-breast irradiation (PBI) using interstitial high-dose-rate brachytherapy (HDR-BT) in comparison with partial-breast electron irradiation (ELE) and whole-breast irradiation (WBI).


METHODS
Between 1998 and 2004, 258 early-stage breast cancer patients were randomized to receive 50 Gy WBI (n = 130) or PBI (n = 128). The latter consisted of either 7 x 5.2 Gy HDR-BT (n = 88) or 50 Gy ELE (n = 40). The incidence of fat necrosis, its impact on cosmetic outcome, accompanying radiologic features, and clinical symptoms were evaluated.


RESULTS
The 4-year actuarial rate of fat necrosis was 31.1% for all patients, and 31.9%, 36.5%, and 17.7% after WBI, HDR-BT and ELE, respectively (p(WBI/HDR-BT) = 0.26; p(WBI/ELE) = 0.11; p(ELE/HDR-BT) = 0.025). The respective rate of asymptomatic fat necrosis was 20.2%, 25.3%, and 10% of patients. The incidence of symptomatic fat necrosis was not significantly different after WBI (8.5%), HDR-BT (11.4%), and ELE (7.5%). Symptomatic fat necrosis was significantly associated with a worse cosmetic outcome, whereas asymptomatic fat necrosis was not. Fat necrosis was detectable with mammography and/or ultrasound in each case. Additional imaging examinations were required in 21% of cases and aspiration cytology in 42%.


CONCLUSIONS
Asymptomatic fat necrosis is a common adverse event of breast-conserving therapy, having no significant clinical relevance in the majority of the cases. The incidence of both symptomatic and asymptomatic fat necrosis is similar after conventional WBI and accelerated partial-breast HDR-BT.
Lövey
Katalin
K
Department of Radiotherapy, National Institute of Oncology, Budapest, Hungary. klovey@oncol.hu
Fodor
János
J
Major
Tibor
T
Szabó
Eva
E
Orosz
Zsolt
Z
Sulyok
Zoltán
Z
Jánváry
Levente
L
Fröhlich
Georgina
G
Kásler
Miklós
M
Polgár
Csaba
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods; D001940:Breast / Q000473:pathology* / Q000528:radiation effects; D001943:Breast Neoplasms / Q000532:radiotherapy*; D004583:Electrons / Q000009:adverse effects / Q000627:therapeutic use; D005218:Fat Necrosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011859:Radiography; D011879:Radiotherapy Dosage