Abstract P4-07-48: Preliminary results of the FIRST (FreezIng bReaST cancer in Brazil) trial: a before-after study

Abstract

Abstract Background: Image-guided tumor ablation is a non-surgical minimally invasive therapy available for the local treatment of carcinomas as an alternative to surgical treatment. However, studies evaluating this therapy in early breast cancer present variable success rates, raising the question of whether omitting surgery is permissible. Ongoing studies such as the Frost and Ice3 Trial may change the context of cryoablation in the treatment of early breast cancer. Objective: The main objective of this study is to assess the effectiveness of cryoablation in the local treatment of early breast cancer. The secondary objectives are to analyze the negative predictive value of magnetic resonance imaging (MRI) in predicting response to therapy and to assess ice ball size in relation to the largest tumor size. Methods: Non-randomized, single-arm, multicenter clinical study conducted in Brazil. The inclusion criteria will be patients with unifocal invasive breast carcinoma, tumors smaller than or equal to 2.5 cm, lesion visualized on ultrasound, and surgery indicated as the first treatment option. The exclusion criteria will be in situ ductal carcinoma, multifocal or multicentric tumors, clinical axillary involvement, lesion-to-skin distance of less than 5 mm, presence of distant metastasis, and neoadjuvant treatment. All patients will undergo local cryoablation treatment, which will be followed by conventional surgical treatment after an interval of 14 to 28 days. Imaging tests (mammography, ultrasound, and breast MRI) will be performed before and after cryoablation. Cryoablation effectiveness will be assessed through its success rate, defined as the absence of invasive or in situ malignant neoplastic cells in the surgical specimen. If the expected cryoablation success rate corroborates the 92% rate presented in the ACOSOG Z1072 study for patients without multifocal disease, this study will need at least 32 patients to verify if the technique is satisfactory (success rate > 70%) considering power of 95% and an alpha of 5%. The study was approved by the local ethics committee and registered in the Clinical Trials. Recruiting has started in 2020 and is expected to end in 2024. Results: Until now, eight patients have been included, all of them with invasive breast carcinoma of no special type, RH positive and HER 2 negative, histological grade 1 or 2. The mean age of the patients is 57 years, and the mean tumor size is 1.1 cm (0.5–1.8 cm). All patients underwent two cycles of 6-minute freezing and 4-minute thawing with only one cryoprobe coupled to the Argon and Helium gas system. The complete ablation rate was 87.5% (7 of 8 cases) and the ablation rate considering only absence of invasive lesion was 100%. In our study, only one patient had in situ focal ductal carcinoma in one margin. The mean ice ball size on ultrasound was 3.8 x the size of the breast lesion. The negative predictive value of breast MRI was 100%. Conclusions Cryoablation is a promising therapy and may be an alternative to surgical treatment in patients with early breast cancer. This study confirms that this ablative technique is feasible. However, the results of other ongoing studies need to confirm the role of cryoablation in breast cancer treatment. ClinicalTrials.gov Identifier: NCT05398497 Citation Format: Vanessa M. Sanvido, Silvio E. Bromberg, Antonio R. Junior, Bruna Mayumi T. Tachibana, Afonso Nazário. Preliminary results of the FIRST (FreezIng bReaST cancer in Brazil) trial: a before-after study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-48.