Abstract P3-13-03: Multicenter clinical trial of percutaneous laser ablation for early stage primary breast cancer. Results of 49 cases with radiographic and pathological correlation
Authors: Schwartzberg BS , Abdelatif OMA , Lewin JM , Bernard JM , Brehm JL , Bu-Ali HM , Cawthorn SJ , Chen-Seeto M , Feldman SM , Govindarajulu S , Jones LI , Juette A , Kavia S , Maganini RO , Pain SJ , Shere MH , Shriver CD , Smith SG , Valencia A , Whitacre EB , Whitney R 
Published: May 2016

Abstract
Introduction: Percutaneous laser ablation of early stage primary breast cancer remains investigational. A multicenter, international clinical trial (NCT01478438) was completed to determine feasibility of this technique.
Methods: Patients with a single focus of biopsy proven infiltrating ductal carcinoma measuring 20 mm or less by pre-ablation MRI were treated by image-guided percutaneous laser ablation. A laser diode source (805 nominal nanometer wavelength) was used to perform the thermal ablation. Thermal sensors placed at the periphery of the tumor measured achievement of predefined temperature levels, indicating successful ablation. The patients were evaluated by post-ablation mammogram, ultrasound and MRI at 4 weeks post-ablation, after which they underwent surgical excision. Pathology specimens were evaluated by hematoxylin & eosin, CK 8/18, Ki-67 and estrogen receptor staining.
Results: Forty-nine of the 61 enrolled patients (ages 42-77, mean age 64 years) undergoing percutaneous laser ablation have finished protocol analysis and are reported in this series. Ablation was considered complete by the treating physician in all cases. The mean tumor size was 11.3 mm. The mean laser time was 15.7 minutes. There were no serious adverse events. Seven patients (14%) reported mild adverse events (pain, blisters, lump). Post-ablation cell viability was determined by MRI and by changes in CK 8/18, Ki67 and estrogen receptor staining. A post-ablation discordance between MRI and pathology was found in evaluation of 4 patients (8%). Three patients (6%) were considered "false negative" with a post-ablation residual tumor burden of less than 2mm which was not detected by MRI. One patient (2%) had a complete pathologic ablation but positive MRI ("false positive"). One patient (2%) had adjacent residual DCIS, visible in retrospect on the pre-ablation MRI and was considered a screening failure. Eight patients (16%) were found to have residual invasive cancer by both post-ablation MRI and pathologic analysis. Complete ablation was confirmed in 36 patients (73%) when evaluated by both post-ablation MRI and pathologic analysis.
Conclusion: Percutaneous laser ablation holds promise as an alternative to lumpectomy in the treatment of early stage breast cancer. There is a strong correlation (92%) between findings on post-ablation MRI and changes in CK 8/18, Ki67 and estrogen receptor staining in this series. Additional trials are necessary to determine the long-term curative potential of this technique.
Citation Format: Schwartzberg BS, Abdelatif OMA, Lewin JM, Bernard JM, Brehm JL, Bu-Ali HM, Cawthorn SJ, Chen-Seeto M, Feldman SM, Govindarajulu S, Jones LI, Juette A, Kavia S, Maganini RO, Pain SJ, Shere MH, Shriver CD, Smith SG, Valencia A, Whitacre EB, Whitney R. Multicenter clinical trial of percutaneous laser ablation for early stage primary breast cancer. Results of 49 cases with radiographic and pathological correlation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-13-03.