A phase II trial of image-guided radiofrequency ablation of small invasive breast carcinomas: use of saline-cooled tip electrode.
BACKGROUND
Local ablative therapy of breast cancer represents the next frontier in the evolution of minimally-invasive breast conservation therapy. We performed this Phase II trial to determine the efficacy and safety of Radiofrequency (RF) ablation of small invasive breast carcinomas.


METHODS
Seventeen patients with biopsy-proven invasive breast cancer, < or = 1.5 cm in diameter were enrolled in this trial. Under ultrasound guidance, the tumor and a 5 mm margin of surrounding breast tissue were ablated with saline-cooled RF electrode followed by surgical resection. Pathologic and immunohistochemical stains were performed to assess tumor viability. We examined whether loss of ER, PR receptor and pancytokeratin expression following RF ablation would correlate with non-viability.


RESULTS
Fifteen patients completed the treatment. The mean tumor size was 1.28 cm. The mean ablation time was 21 minutes using a mean power of 35.5 watts. During ablation, the tumors became progressively echogenic that corresponded with the region of severe electrocautery injury at pathological examination. Of the 15 treated patients, NADPH viability staining was available for 14 patients and in 13 (92.8%), there was no evidence of viable malignant cells. ER, PR expression and pancytokeratin immunohistochemistry analysis were unreliable surrogates for determining non-viability. Following RF ablation, 2 patients developed skin puckering.


CONCLUSIONS
RF ablation is a promising minimally invasive treatment of small breast carcinomas, as it can achieve effective cell killing with a low complication rate. Further research is necessary to optimize this image-guided technique and evaluate its future role as the sole local therapy.
Khatri
Vijay P
VP
Division of Surgical Oncology, University of California, Davis, Sacramento, USA. vijay.khatri@ucdmc.ucdavis.edu
McGahan
John P
JP
Ramsamooj
Rajendra
R
Griffey
Stephen
S
Brock
John
J
Cronan
Michael
M
Wilkendorf
Stephen
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000601:surgery*; D017115:Catheter Ablation; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008408:Mastectomy; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D009361:Neoplasm Invasiveness / Q000473:pathology; D021701:Sentinel Lymph Node Biopsy; D016217:Ultrasonography, Mammary