Circulating Tumor DNA After Neoadjuvant Chemotherapy

Inclusion criteria

• Age ≥ 18 years (no age limit).
• Women or men.
• Invasive breast cancer proven histologically at diagnosis (before neoadjuvant chemotherapy):
• Locally advanced tumor known to be inoperable from the start:
• cT4a, b, c, d whatever the cN
• or cN2 or cN3 whatever the cT.
• Operable tumors:
• cT2cN1 or cT3cN0 or cT3N1,
• or cT2cN0 for which ganglionic invasion has been proven by cytology or histology.
• Lack of clinically or radiologically detectable metastases in the initial diagnosis before the neoadjuvant chemotherapy (M0).
• Unilateral or bilateral breast cancer. Multifocality is accepted.
• Patients who received 6 to 8 cycles of neoadjuvant chemotherapy.
• Preoperative radiation therapy allowed.
• Breast surgery performed and pathology report of a non-complete histological response (i.e. all the different results of ypT0 /is ypN0).
• Signed informed consent.
• Patients affiliated to a French social security scheme in accordance with Article 1121-11 of the French Code of Public Health.
• Possible inclusion in another interventional research (surgical, radiotherapy or drug study).

Exclusion criteria

• cT2cN0 tumor without cytological or histological lymph node involvement.
• Progression during neoadjuvant chemotherapy.
• Exclusive neoadjuvant hormone therapy.
• Complete blood transfusion within 120 days prior to 1st sampling.
• History of invasive cancer regardless of the time elapsed since the diagnosis of this cancer, including a history of contralateral invasive breast cancer. However, patients who have been treated for in situ breast cancer, basocellular skin cancer or cervical cancer treated in situ are eligible.
• Patient unable to follow and comply with research procedures for geographical, social or psychological reasons.
• Patient deprived of liberty or subject to a legal protection measure.