Comprasion of methods of margin delineation for vaccum-assisted excision in Breast cancer patients with radilogical complete response post neoadjuvant chemotherapy

Breast cancer is currently the most common cancer among women in India, with most cases being diagnosed at advanced stages. There is a growing role of NACT for management of breast cancer with some chemotherapy resulting in complete disappearance of the mass on preoperative imaging. However, a radiological complete response may not corroborate with pathological complete response in about 60% of patients, necessitating the need for surgical resection of the tumour bed.

Ultrasound or Mammography guided Vacuum Assisted tumour bed Excision (VAE) is an attractive minimally invasive option for tumor resection in certain scenarios like in patients with complete radiological response which is under investigation worldover to prove or disprove complete pathological response. Several studies indicate that adequate Vacuum Assisted Excision can accurately determine whether pathological complete response has been achieved, thus introducing the possibility of surgical deescalation. However since vacuum involves suction of tissue, margin determination is impossible.

However,  accurate excision of the entire tumor bed with adequate margin determination is important to prevent local recurrence which however is quite challenging at present. We propose and compare two methods of margin determination for VAE along with protocol for performing VAE. The 1st method is using two wires for bracketing the tumor bed t. The 2nd approach utilizes multidirectional VAE in the epicenter of tumor bed and a fixed predetermined distance around it for adequate excision. Additionally, we also propose to collect the data of the patient for development of machine learning techniques to identify the margins of the tumor bed in real time and thus guide VAE. .