Thermal ablation of the goat mammary gland as a model for post-lumpectomy treatment of breast cancer: preliminary observations.
BACKGROUND
Partial breast irradiation post-lumpectomy, with a balloon bearing a radioactive source in its center, is practiced as an alternative to whole breast irradiation in the treatment of breast cancer. The goal is to ablate residual malignant cells within 1 cm radius of the resected lumpectomy margin. We hypothesize that this goal may be achieved with a fluid-filled heated balloon.


METHODS
Nubian-cross goats were treated under general anesthesia. The two mammary glands were sequentially bisected and a non-inflated balloon with a heating element was placed in the center of the gland which was re-sutured. Two series of experiments were conducted. In the first 22 goats (44 glands), the balloon was inflated with 5% dextrose to a pressure of 150 mmHg and heated at 87 degrees C over selected time intervals of 1-24 minutes. In the second series (16 glands), the re-programmed device operated at 50-80 mmHg over selected time intervals of 5-20 minutes. The depth of necrosis was histologically determined after sacrificing the goats and excising the glands.


RESULTS
In the first series, glandular necrosis was noted to extend to a depth of 3.2-9.6 mm for the above heating cycles. Corresponding figures for the second series ranged from 4.7-8.6 mm for treatment times of one minute 'warm up' to 20 minutes of heating at 90 degrees C. The animals exhibited no systemic side effects post-treatment.


CONCLUSIONS
An experimental model describing a thermal technique causing necrosis of the goat mammary gland is described.
Alvarado
R
R
Department of Surgery, Rush University Medical Center, Chicago, Illinois, USA.
Mahon
B
B
Valadez
C
C
Caufield
M
M
Wadhwani
S
S
Hambleton
C
C
Siziopikou
K P
KP
Dickler
A T
AT
Gatta
J
J
Dowlatshahi
K
K
D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D002404:Catheterization / Q000379:methods; D005260:Female; D006041:Goats / Q000601:surgery*; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008321:Mammary Glands, Animal / Q000473:pathology / Q000601:surgery; D015412:Mastectomy, Segmental / Q000379:methods; D009336:Necrosis / Q000473:pathology