Change in seroma volume during whole-breast radiation therapy.
OBJECTIVE
After breast-conserving surgery, a seroma often forms in the surgical cavity. If not drained, it may affect the volume of tumor bed requiring a boost after whole-breast radiation therapy (WBRT). Our objective was to evaluate the change in seroma volume that occurs during WBRT, before boost planning.


METHODS
A retrospective review was performed of women receiving breast-conserving therapy with evidence of seroma at the time of WBRT planning. Computed tomography (CT) simulation was performed before WBRT and before the tumor bed boost. All patients received either a hypofractionated (42.4 Gy/16 fraction + 9.6 Gy/4 fraction boost) or standard fractionated (50.4 Gy/28 fraction + 10 Gy/5 fraction boost) regimen. Seroma volumes were contoured and compared on CT at the time of WBRT simulation and tumor bed boost planning.


RESULTS
Twenty-four patients with evidence of seroma were identified and all patients received WBRT without drainage of the seroma. Mean seroma volume before WBRT and at boost planning were significantly different at 65.7 cm(3) (SD, 50.5 cm(3)) and 35.6 cm(3) (SD, 24.8 cm(3)), respectively (p < 0.001). Mean and median reduction in seroma volume during radiation were 39.6% (SD, 23.8%) and 46.2% (range, 10.7-76.7%), respectively. Fractionation schedule was not correlated with change in seroma volume. Length of time from surgery to start of radiation therapy showed an inverse correlation with change in seroma volume (Pearson correlation r = -0.53, p < 0.01).


CONCLUSIONS
The volume of seroma changes significantly during WBRT. Consequently, the accuracy of breast boost planning is likely affected, as is the volume of normal breast tissue irradiated. CT-based boost planning before boost irradiation is suggested to ensure appropriate coverage.
Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA.
Rajiv
R
Sharma
Marnee
M
Spierer
Subhakar
S
Mutyala
Nitika
N
Thawani
Hillel W
HW
Cohen
Linda
L
Hong
Madhur K
MK
Garg
Shalom
S
Kalnicki
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000601:surgery; D002278:Carcinoma in Situ / Q000000981:diagnostic imaging / Q000532:radiotherapy / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000532:radiotherapy / Q000601:surgery; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental / Q000009:adverse effects; D008875:Middle Aged; D009929:Organ Size; D012189:Retrospective Studies; D049291:Seroma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D013997:Time Factors; D014057:Tomography, X-Ray Computed