Non-Invasive Three-Dimensional Breast Tumor Positioning Before Neoadjuvant Systemic Therapy as Promissing Alternative to the Invasive Tumor Marking – Technique Description and Feasibility

Abstract

Abstract Background: Surgical excision of the lodge of the tumor that has completely clinically regressed after neoadjuvant systemic therapy (NAST) is a necessary part of the treatment of early breast cancer. However, it is significantly hampered by the lack of a spatial landmark concerning the location of the pre-existing tumor in the breast. Standard surgical techniques of targeted excision of the pre-existing tumor bed generally rely on invasive insertion of various markers into or around the tumor before starting NAST. Invasive marking techniques are burdened by the disadvantages of technical complexity, invasiveness of procedures, and insufficient precision. Methods: In this paper authors present an original technique of non-invasive determining of the tumor position in the breast in three dimensions before starting NAST, with intention to overcome the disadvantages of invasive tumor marking. Tumor positioning is performed by ultrasound measurements – detailed description of the technique is given in the main text. The feasibility and precision of the technique was tested by the histological parameters of the adequacy and rationality of excision of the tumor bed, after complete clinical regression of the tumor after NAST, on a pilot series of patients. Results: A pilot series of 33 patients underwent a non-invasive breast tumor positioning technique before starting NAST. Twelve patients with complete clinical regression after NAST have been operated using a non-invasive tumor positioning technique, so far. In all cases, histological signs of tumor regression were verified in the specimen of the excised tumor bed. The ratio of the resected specimen volume to the volume of the tumor before NAST was on average 0,91, which is in favor of the rationality of excision and a good aesthetic effect. Conclusion: The initial results of a pilot series of treated patients imply that a non-invasive three-dimensional tumor positioning technique is feasible, with a satisfactory level of oncological safety and aesthetic effects of surgery. Performing a randomised clinical trial comparing this technique with standard techniques of invasive tumor marking is justified.