Interfraction accumulation of seroma during accelerated partial breast irradiation: preliminary results of a...

To quantify and characterize the process of seroma accumulation during accelerated partial breast irradiation using multicatheter balloon brachytherapy.

Twenty-two patients were treated using the Contura Multilumen brachytherapy catheter to a dose of 34Gy in 10 fractions over 5 treatment days. Serial aspirations of the vacuum port of the catheter were performed at the time of CT simulation and before each treatment. Volume and characteristics of fluid drawn were recorded. Univariate analysis was performed to evaluate various factors predictive of seroma formation.

Median patient age was 59.5 years, body mass index was 31, and volume of surgical specimen was 62.4cm(3). Median time from breast conservation surgery to placement of Contura catheter was 18.5 days. Pericatheter seroma, typically scant with a median volume of 0.75mL, was noted in 91% of patients at CT simulation. A total of 203 aspirations were performed with a median-aspirated seroma volume of 4.05mL. There was no significant correlation between the volume of seroma and histology (invasive vs. in situ), quadrant of location, body mass index, reexcision or reoperation, days from breast conservation surgery to balloon placement, or the volume of specimen removed. Radiation treatment factors, including balloon volume, balloon to skin distance, and planning target volume evaluation, also did not correlate with aspirated seroma.

Interfraction seroma accumulation has a variable pattern of development with no discernible predictors of occurrence. Routine pretreatment aspirations via vacuum port may potentially improve dosimetric reproducibility for a minority of patients.