Abstract: Invasive Ductal Carcinoma of the Breast and the Role of Neoadjuvant Chemotherapy Before Resection
Background
Breast cancer remains the most commonly diagnosed malignancy in women worldwide, with invasive ductal carcinoma (IDC) representing approximately 70-80% of all invasive breast cancers. The incidence of breast cancer varies globally, with approximately 2.3 million new cases diagnosed annually, and mortality rates have been declining due to improved screening and treatment strategies.
Case Presentation
This case report examines a patient with invasive ductal carcinoma of the breast who underwent neoadjuvant chemotherapy prior to surgical resection. Neoadjuvant chemotherapy serves multiple critical roles in the management of IDC, including tumor downstaging to enable breast-conserving surgery, assessment of tumor chemosensitivity, and achievement of pathological complete response, which correlates with improved survival outcomes 1.
The National Comprehensive Cancer Network guidelines establish that neoadjuvant chemotherapy increases breast conservation rates compared to upfront surgery, though it demonstrates no disease-specific survival advantage over postoperative adjuvant chemotherapy in stage II tumors 1. The NSABP B-18 trial documented higher breast conservation rates following preoperative chemotherapy, while the NSABP B-27 trial demonstrated that adding docetaxel to doxorubicin and cyclophosphamide increased pathological complete response rates 1.
For HER2-positive IDC, the incorporation of trastuzumab into neoadjuvant chemotherapy regimens is essential, increasing pathological complete response rates from 26% to 65.2% 1. The recommended regimens from the adjuvant setting are appropriate for neoadjuvant use, including dose-dense AC followed by paclitaxel, or TCH (docetaxel, carboplatin, trastuzumab) for HER2-positive disease 1.
Pathological complete response, defined as ypT0/isypN0 or ypT0ypN0, represents absence of residual invasive carcinoma in both breast and axillary lymph nodes and correlates with substantial improvements in survival 1. The FDA-supported pooled analysis of 12 neoadjuvant trials demonstrated similar event-free survival and overall survival in patients without residual invasive carcinoma regardless of residual DCIS presence 1.
Clinical Implications
Invasive ductal carcinoma demonstrates significantly superior response to neoadjuvant chemotherapy compared to invasive lobular carcinoma, with IDC achieving pathological complete response in 22.1% versus 7.4% for ILC 2. This differential response translates to higher breast-conserving surgery rates (45.7% vs. 33.3%) and lower positive margin rates (13.5% vs. 36%) in IDC patients 2.
Critical technical considerations include percutaneous clip placement under mammographic or ultrasound guidance before initiating chemotherapy to localize the prechemotherapy tumor volume, facilitating accurate postchemotherapy resection 1. Prechemotherapy sentinel lymph node excision provides additional information to guide local and systemic treatment decisions, as the false-negative rate remains low in both pre- and postchemotherapy settings 1.
Radiation therapy indications and treatment fields should be based on pretreatment tumor characteristics in patients receiving neoadjuvant chemotherapy 1. Following tumor response to preoperative chemotherapy, lumpectomy with appropriate axillary staging may be considered if breast-conserving therapy requirements are fulfilled 1.
Conclusion
This case demonstrates the multifaceted role of neoadjuvant chemotherapy in invasive ductal carcinoma management, enabling tumor downstaging, increasing breast conservation opportunities, and providing prognostic information through pathological response assessment, while maintaining equivalent survival outcomes to adjuvant chemotherapy approaches.