Evaluation of the Accuracy of Percutaneous Biopsy by Vacuum-assisted Biopsy (VAB) to Assess Pathological Complete Response in Patients With Clinical and Radiological Complete Response After Neoadjuvant Chemotherapy (NeoVAB)
Evaluation of the Accuracy of Percutaneous Biopsy by Vacuum-assisted Biopsy (VAB) to Assess Pathological Complete Response in Patients With Clinical and Radiological Complete Response After Neoadjuvant Chemotherapy (NeoVAB)
Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death in
 females in the world. Neoadjuvant chemotherapy (NAC) is increasingly used in patients with
 operable breast cancer to enhance the likelihood of breast conservation. New generation of
 treatments or combinations lead to a high rate of pathological complete responses (pCR) in
 patients with human epidermal growth factor receptor 2 positive (HER2) and triple negative
 tumours. Safe omission of surgery in patients who receive NAC and achieve radiologic complete
 response depends on the ability to accurately estimate pCR preoperatively.

 If pathological complete response after NAC could be accurately assessed by VAB, surgery
 could be avoided. In the context of new treatments or combinations with an increased pCR
 rate, this new strategy could induce major changes in clinical practice, leading to breast
 surgery de-escalation.
A total of 66 patients will be submitted to percutaneous vacuum-assisted biopsy (VAB),
 followed by breast surgery. The primary endpoint of the study is the false negative rate of
 VAB procedure. This rate will be calculated by comparing the detection of invasive or in situ
 carcinoma on surgical specimen versus VAB samples. The secondary endpoints of the study are
 feasibility, VAB procedure technical complications and safety.
Inclusion Criteria:

 1. Patient aged 18 years or older.

 2. Written informed consent provided.

 3. Triple negative or HER2-positive / ER-negative or HER2-positive / ER-positive breast
 tumours.

 4. Patients eligible for breast conservation after NAC.

 5. Patients with T2-T3 N0 invasive breast cancer initially treated by NAC to allow breast
 conservation, who have received a minimum of 6 cycles of adequate NAC +/- anti-HER2.

 6. Clinical complete response after NAC.

 7. Radiological (mammography, breast US, breast MRI) complete response after NAC.

 8. Patients predicted to be node-negative at treatment initiation.

 Exclusion Criteria:

 1. Patient younger than 18 years old.

 2. Pregnant or breastfeeding women.

 3. Proven metastatic axillary or internal mammary chain lymph node involvement before NAC
 proven by biopsy or cytology.

 4. Bilateral breast cancer.

 5. Contraindication to MRI.

 6. Contraindication to breast conservation

 7. Patients with a BRCA mutation or other autosomal dominant high-penetrance genetic
 predisposition to breast cancer.

 8. Patients with limitation of freedom or under guardianship

 9. Inability for psychological reasons

 10. Hypersensitivity to local anaesthesia

 11. Initial imaging showing ACR6 micro calcifications and/or ACR6 non-mass enhancement
 associated to the index lesion