Breast Cancer (Triple Negative Breast Cancer (TNBC))

The goal of this observational, retrospective, non interventional study is to learn about the efficacy of an Anthracycline-Free Neoadjuvant Chemoimmunotherapy in Early Triple-Negative Breast Cancer (TNBC). The main question it aims to answer is : \- What is the efficacy of this kind of treatment, by evaluating the pathological complete response (PCR), that is to say, the percentage of patients where no tumor cells remained when they underwent surgery after neoadjuvant treatment. The other points that will be evaluated are: * The treatment regimen * The epidemiological characteristics of the treated population * The efficacy by relapse-free survival ; overall survival * The tolerability and adverse effects The standard treatment for localized TNBC (larger than 2 cm or with lymph node involvement) is neoadjuvant chemoimmunotherapy, which includes anthracyclines. However, in real-world practice, some patients have a contrindication to this treatment because they have received it previously, are too old, or have comorbidities, particularly cardiovascular disease. Currently, there is limited data on the modalities and efficacy of such treatment.

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and work by blocking protein interactions that normally prevent the immune system from recognizing and destroying cancer cells. However, these agents, now approved for over 15 types of cancers and for both early-stage and metastatic disease, are capable of causing inflammation in any organ system of the body that can lead to organ damage, dysfunction, and even death in rare cases. Some patients may suffer acute and treatable complications like joint pain, but some may have irreversible complications like hypothyroidism that requires daily, life-long medication. It is therefore important to fully understand the different types of damage ICIs can cause to better monitor patients receiving ICI therapy. A rising concern from recent reports in the literature is that ICIs may weaken bone and increase the risk of fractures. In this study, the investigators aim to characterize how ICIs impact the bone by examining several factors in patients undergoing curative-intent ICI treatment either alone or in combination with chemotherapy: bone mineral density, bone volume, and markers of bone turnover in the blood. The study will use two imaging techniques to assess bone mineral density and volume. DXA (dual X-ray absorptiometry) imaging uses low-dose X-rays to measure how dense (or strong) bones are and is often used to diagnose or assess the risk of osteoporosis. High-resolution peripheral quantitative computed tomography (HRpQCT) is a 3D imaging technology that can quantify bone structure and volume and offers high resolution that can be used to assess bone in smaller bones of the peripheral skeleton. The investigators hypothesize that ICI treatment will weaken bones and increase the risk of fractures. As ICI therapy is relatively new, a rising number of patients may be at risk of fractures or have low bone density that is not being monitored because there are no guidelines in place notifying physicians of this potential risk to patients. This is study will provide important preliminary data that will be the basis for larger studies in the future aiming to better monitor and potentially treat bone weakening in patients treated with ICIs to reduce the pain, inconvenience, and complications from fragility fractures.

The study is being conducted to explore the reasonable dosage and evaluate the efficacy, safety and tolerability of HLX43 (Anti-PD-L1 ADC) as a monotherapy or in combination with immune checkpoint inhibitors in Subjects with locally advanced, recurrent or metastatic triple-negative breast cancer (TNBC).