De-Escalation Surgery in cT3-4 Breast Cancer Patients after Neoadjuvant Therapy: Predictors of Breast Conservation and Comparison of Long-Term Oncological Outcomes with Mastectomy

Abstract

Background: Neoadjuvant therapy (NAT) has become increasingly employed for the treatment of cT3-4 breast cancer (BC), enabling breast-conserving surgery (BCS) in cases traditionally considered for mastectomy. This study aims to identify predictors for breast conservation post-NAT and to evaluate whether BCS influences long-term oncological outcomes. Methods: We retrospectively analyzed data from patients with cT3-4 BC who received NAT at the Breast Unit of IRCCS Humanitas Research Hospital, Milan, Italy, from October 2009 to April 2020. Surgical outcomes and long-term oncological results, such as disease-free survival (DFS), distant DFS (DDFS), overall survival (OS), and BC-specific survival (BCSS), were compared between the BCS and mastectomy groups. Results: Among 114 patients analyzed, 37 (32.5%) underwent BCS, and 77 (67.5%) had a mastectomy. The key predictors for opting for BCS included absence of vascular invasion, reduced tumor size post-NAT, and achieving ypT0 status. No significant differences in DFS, DDFS, OS, and BCSS were observed between the two surgical groups (log-ranks, p = 0.520, p = 0.789, p = 0.216, p = 0.559, respectively). Conclusions: BCS after NAT is a feasible and safe option for patients with cT3-4 BC, without adversely affecting long-term oncological outcomes. Identifying predictors of breast conservation can guide surgical decision-making, ensuring that patients receive optimal treatment.

The Role of MRI in Breast Cancer and Breast Conservation Therapy

“…Invasion into the nipple-areolar complex [66] Presence of a MRI incompatible implantable device Multicentric/multifocal disease [68] Mammographically occult disease in contralateral breast [17,[69][70][71][72][73][74] Metastatic involvement of axillary or IMN nodes [36,52,[77][78][79]91,96,97] Tumor response to NAT [57][58][59]70,[120][121][122][123][127][128][129][130] Post treatment changes in the breast Non-ionizing radiation The normal appearance of the breast following partial mastectomy often includes a seroma at the surgical site (Figure 11). Seromas and surgical cavities containing fluid will demonstrate increased T2/STIR signal and be most conspicuous on a fluid-sensitive sequence (Figure 11A).…”

“…High sensitivity [5][6][7][8][9][10] Cost Tumor size estimation [55][56][57][58][59] Accessibility Defining extent of disease Claustophobia Pectoralis major/minor invasion [64,65] IV gadolinium contrast allergy (rare) Invasion into the nipple-areolar complex [66] Presence of a MRI incompatible implantable device Multicentric/multifocal disease [68] Mammographically occult disease in contralateral breast [17,[69][70][71][72][73][74]] Metastatic involvement of axillary or IMN nodes [36,52,[77][78][79]91,96,97] Tumor response to NAT [57][58][59]70,[120][121][122][123][127][128][129][130] Post treatment changes in the breast Non-ionizing radiation…”

“…Neoadjuvant therapy (NAT) can allow more patients to undergo breast conservation by reducing the primary tumor size in patients that otherwise would have been ineligible [ 120 , 121 ], and MRI has a significant role in assessing the response to therapy. Several factors have been shown to affect the predictive value and diagnostic accuracy of MR imaging in the assessment of treatment response to NAT, including tumor molecular subtype, tumor imaging phenotype, the chemotherapeutic regimen, and the pathology response criteria utilized for assessment.…”