Can a Pathological Complete Response in the Breast be Diagnosed by Vacuum-assisted, Ultrasound Guided Minimal Invasive Biopsy After Neoadjuvant Chemotherapy in Breast Cancer Patients? A Proof of Concept From a Prospective Cohort Study

Neoadjuvant chemotherapy (NACT) is an increasingly used approach for patients with locally advanced and primarily inoperable breast cancer or for patients with potentially chemosensitive tumors. In clinical routine surgical treatment follows the pre-operative chemotherapy. However, recent studies have demonstrated that shrinking tumors need less surgical treatment indicating that patients with pCR could potentially be spared of surgery in the future.

Up to now, prediction of pCR after NACT, i.e. diagnosing a pCR without surgery, is based on tumor biology at diagnosis, the applied NACT regimen and breast imaging results; all with mediocre accuracy. This prospective, monocenter diagnostic trial aims to explore if minimal invasive biopsies (MIB) might overcome this diagnostic challenge.

From September 1st, 2014 to February 15th, 2015 the investigators performed ultrasound guided vacuum-assisted minimal invasive biopsy (VAB) on 50 breast cancer patients after NACT and directly prior to surgery. To analyse VAB pathologically results were categorized as follows: residual vital tumor cells (invasive, in situ, both, lymphangiosis carcinomatosous) present, (significant parts of) the tumor bed present, neither vital tumor cells nor (significant parts of) the tumor bed (indicating a non representative VAB). The results were compared to those of the pathological examination of surgical specimen.