Refusal of Breast Surgery in Patients With Breast Cancer With a Clinical Complete Response (cCR) After Neoadjuvant Systemic Therapy and a Confirmed Pathological Complete Response (pCR) Using Vacuum-assisted Biopsy (VAB) and Sentinel Lymph Node Biopsy (SLNB)

Vacuum-assisted removal and biopsy of the tumor bed after neoadjuvant systemic therapy (NST) in patients with clinical complete clinical response with a biopsy of sientinel lymph nodes is in the future a modern alternative to the standard, often crippling and traumatic surgical procedures and does not require additional financial costs for the reconstruction of the breast.

There are only two trial visits that are specific to the trial. All other visits will be routine visits.

The first trial visit before NST will take place in order to provide the patient with detailed information on the study, its' aims, the VAB procedure, and its risks. The patient will be asked to sign a form of informed consent.

In the second visit after the NST, VAB planning will be carried out. This visit may vary depending on the patient, the tumor, and the characteristics of the study site. We will provide each test participant with the opportunity to choose the appropriate conditions for the procedure.

The VAB procedure with a sentinel lymph node biopsy will be performed in the operating room Research objectives

• To evaluate the frequency of coincidence of the clinical complete or partial response (cCR and PR) with pathological complete response (pCR).
• To study the frequency of detecting a residual tumor in the mammary gland using a Vacuum-assisted biopsy or another type of core biopsy and / or detection of metastases in regional lymph nodes (sentinel lymph node biopsy) in comparison with a standard pathological study of the surgical material and regional (including sentinel ) lymph nodes.
• To analyze the frequency of false-positive conclusions of a vacuum aspiration biopsy of the tumor bed about the achievement of pathological complete response (pCR) in comparison with a standard pathological study of a surgical material.
• To study the long-term results (local-regional relapse, survival) of surgical treatment of patients with clinical complete response (cCR) after neoadjuvant systemic therapy, including residual disease compared with patients who achieved pathological complete response (pCR).
• To develop an algorithm for treating patients with clinical complete response, with a confirmed pathological complete response using a tumor bed biopsy and targeted biopsy of sentinel lymph nodes (taking into account the initial characteristics: age, stage with TNM, disease subtypes, the presence of a genetic mutation BRCA1 / 2).

Ultrasound guided VAB will be performed on breast cancer patients with clinical complete response (cCR) after NST.

The pathological results of the VAB specimen will be generally categorized as follows:

• Residual tumor cells in VAB specimen (=non-pCR)
• No residual tumor cells in the VAB specimen and VAB representative of former tumor region (="pCR in VAB")
• No residual tumor cells in the VAB specimen but VAB unclear or not representative of former tumor region (=possible sampling error). These VABs are categorized as uninformative for the primary endpoint of the clinical trial.

The results will be compared with the results of a pathological examination of a surgical material.

Inclusion criteria

Triple negative breast cancer / HER2-positive breast cancer (ER / PR +/-)

• age> 18 years.
• morphologically confirmed diagnosis of breast cancer, IIA-IIIA stage
• ECOG score 0-1.
• life expectancy of more than 3 months.
• the consent of patients to use reliable methods of contraception throughout the study
• adequate liver and bone marrow function
• the absence of contraindications to surgical intervention (including anesthetic risk is taken into account).

Exclusion criteria

• Inconsistency with inclusion criteria.
• Conducting earlier any systemic therapy for breast cancer.
• stage 4 cancer
• carrier mutations of the BRCA1 / 2 gene
• severe uncontrolled concomitant chronic diseases or acute diseases
• the presence of a second malignant tumor
• pregnancy or lactation
• acute conditions and complications, which, according to the doctor, interfere with treatment