Neoadjuvant chemotherapy is widely used in the treatment of locally advanced breast cancer or in early stages of triple-negative or HER2 overexpressing tumors. Pathological complete response (pCR) to neoadjuvant chemotherapy is associated with better clinical outcomes. However, confirmation of pCR still depends on surgery, which may represent overtreatment for some patients. In this context, image-guided vacuum-assisted percutaneous biopsy (VAB) has been investigated as an alternative to assess tumor response and potentially avoid breast surgery in the future. However, there are no studies evaluating this strategy in brazilian patients, the majority of whom present with locally advanced tumors at diagnosis.
Neoadjuvant chemotherapy is widely used in the treatment of locally advanced breast cancer or in early stages of triple-negative or HER2 overexpressing tumors. Pathological complete response (pCR) to neoadjuvant chemotherapy is associated with better clinical outcomes. However, confirmation of pCR still depends on surgery, which may represent overtreatment for some patients. In this context, image-guided vacuum-assisted percutaneous biopsy (VAB) has been investigated as an alternative to assess tumor response and potentially avoid breast surgery in the future. However, there are no studies evaluating this strategy in brazilian patients, the majority of whom present with locally advanced tumors at diagnosis. To evaluate the accuracy of VAB in predicting mammary anatomopathological response in breast cancer patients undergoing neoadjuvant chemotherapy. This is a cross-sectional study conducted at the Cancer Institute of the State of São Paulo (ICESP). It will include patients with invasive mammary carcinoma cT1-T3, N0-N1, M0, of any immunohistochemical profile, with complete clinical and imaging response or residual lesion ≤ 2 cm after neoadjuvant chemotherapy. VAB will be guided by ultrasound or stereotaxy, with at least six fragments obtained and shaving of the remaining area. The concordance between VAB findings and surgical specimen will be analyzed by sensitivity, specificity, and accuracy.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
100
Patients with an indication for neoadjuvant chemotherapy will be referred for clipping the lesion diagnosed with breast cancer in order to allow subsequent localization of its topography in cases of good response or complete response to treatment. This procedure will be guided by ultrasound, and a specific material consisting of a cannula containing a clip inside is used. Through ultrasound, the cannula is inserted into the center of the target lesion and the clip is positioned at this topography. To allow the clip to be located by ultrasound, it must have a shape that minimizes migration after being positioned, as well as characteristics and dimensions that make it visible on ultrasound, as this method will be preferred for performing the biopsy of the lesion region after neoadjuvant chemotherapy.
Patients with no residual lesion or residual lesion ≤2 cm on MRI and mammography will undergo vacuum-assisted biopsy (VAB) targeting the primary lesion, using the pre-placed clip as a reference under ultrasound or stereotactic guidance. Initially, 6-12 tissue samples will be obtained (7-10G needle) from the clip region, with specimen radiography performed to confirm clip retrieval; additional sampling will continue if the clip is not identified. This initial sample (AM1) will be formalin-fixed. A second set of 6-12 samples will then be collected from the margins of the biopsy cavity ("shaving") and fixed separately (AM2). Following sampling, a new clip will be placed at the biopsy site, and mammographic imaging will confirm its position. The final clip will guide subsequent surgical resection.
Instituto do Câncer do Estado de São Paulo - ICESP
São Paulo, São Paulo, Brazil
Sensitivity, Specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of Vacuum-Assisted Biopsy (VAB) in Detecting Pathological Complete Response (pCR) Compared to Surgical Specimen Histopathology
To evaluate the accuracy of vacuum-assisted percutaneous biopsy in predicting mammary anatomopathological response in breastcancer patients undergoing neoadjuvant chemotherapy. The diagnostic accuracy of VAB will be assessed by calculating sensitivity, specificity, PPV, NPV, and overall accuracy using the surgical specimen histopathological analysis as the reference standard (gold standard).
Time frame: From completion of neoadjuvant chemotherapy to definitive breast surgery
Rate of Complete Residual Lesion Removal by Vacuum-Assisted Biopsy (VAB) Confirmed by Surgical Specimen Histopathology
To evaluate the ability to completely remove residual lesions after chemotherapy in breast cancer using vacuum-assisted percutaneous biopsy. Complete residual lesion removal will be defined as the absence of residual invasive carcinoma or DCIS in the VAB specimens, confirmed by the absence of residual tumor in the surgical specimen. Results will be expressed as a proportion (%) of participants achieving complete lesion removal.
Time frame: From VAB procedure to surgical resection
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