Introduction: Neoadjuvant chemotherapy in breast cancer offers the possibility to facilitate breast and axillary surgery; it is a test of chemosensibility in vivo with significant prognostic value and may be used to tailor adjuvant treatment according to the response. Material and Methods: A retrospective single-institution cohort of 482 stage II and III breast cancer patients treated with neoadjuvant chemotherapy based on anthracycline and taxans, plus antiHEr2 in Her2-positive cases, was studied. Survival was calculated at 5 and 10 years. Kaplan–Meier curves with a log-rank test were calculated for differences according to age, BRCA status, menopausal status, TNM, pathological and molecular surrogate subtype, 20% TIL cut-off, surgical procedure, response to chemotherapy and the presence of vascular invasion. Results: The pCR rate was 25.3% and was greater in HER2 (51.3%) and TNBC (31.7%) and in BRCA carriers (41.9%). The factors independently related to patient survival were pathology and molecular surrogate subtype, type of surgery, response to NACT and vascular invasion. BRCA status was a protective prognostic factor without reaching statistical significance, with an HR 0.5 (95%CI 0.1–1.4). Mastectomy presented a double risk of distant recurrence compared to breast-conservative surgery (BCS), supporting BCS as a safe option after NACT. After a mean follow-up of 126 (SD 43) months, luminal tumors presented a substantial difference in survival rates calculated at 5 or 10 years (81.2% compared to 74.7%), whereas that for TNBC was 75.3 and 73.5, respectively. The greatest difference was seen according to the response in patients with pCR, who exhibited a 10 years DDFS of 95.5% vs. 72.4% for those patients without pCR, p < 0001. This difference was especially meaningful in TNBC: the 10 years DDFS according to an RCB of 0 to 3 was 100%, 80.6%, 69% and 49.2%, respectively, p < 0001. Patients with a particularly poor prognosis were those with lobular carcinomas, with a 10 years DDFS of 42.9% vs. 79.7% for ductal carcinomas, p = 0.001, and patients with vascular invasion at the surgical specimen, with a 10 years DDFS of 59.2% vs. 83.6% for those patients without vascular invasion, p < 0.001. Remarkably, BRCA carriers presented a longer survival, with an estimated 10 years DDFS of 89.6% vs. 77.2% for non-carriers, p = 0.054. Conclusions: Long-term outcomes after neoadjuvant chemotherapy can help patients and clinicians make well-informed decisions.

Introduction: Neoadjuvant chemotherapy in breast cancer offers the possibility to facilitate breast and axillary surgery, it is a test of chemosensibility in vivo with significant prognostic value and may tailor adjuvant treatment according to response. Material and Methods: a retrospective single institution of 482 stage II and III breast cancer patients treated with neoadjuvant chemotherapy based on anthracycline and taxans plus antiHEr2 in those Her2 positive cases. Survival was calculated at 5 and 10 years. Kaplan Meier with log rank test were calculated for difference according to TNM, pathological and molecular surrogated subtype, TILs cut-off 20%, response to chemotherapy and the presence of vascular invasion. Results: In the univariate those factors that influenced long-term patient outcome were TNM (p=0.000); pathologic subtype (p=0.003); Tils cut off 20%; achieving pCR (p=0.000), RCB (p=0.000) and vascular invasion (p=0.000). After a mean follow up of 126 months, Luminal tumors presented a substantial difference of survival rates calculated at 5 or 10 years (81.2% compared to 74.7%) whereas for TNBC was 75.3 and 73.5, respectively. The greatest difference was seen according to response those patients with pCR presented a 10yDDFS of 95.5 vs 72.4% for those patients without pCR. This difference was especially meaningful in TNBC were 10y DDFS according to the RCB 0 to 3 was 100%, 80.6%, 69% and 49.2% respectively. Patients with a special bad prognosis in our series were lobular carcinomas with 10y DDFS of 42.9% vs 79.7%, p= 0.001 for ductal carcinomas; and those patients with vascular invasion at the surgical specimen with a 10yDDFS of 59.2% vs 83.6, p=0.,000 for those patients without vascular invasion. Conclusion: long-term outcomes after neoadjuvant chemotherapy can help patient and clinician make well-informed decisions.

Background/Objectives: Tumor-infiltrating lymphocytes (TILs) are recognized predictors of response to neoadjuvant chemotherapy (NACT) and prognosis in breast cancer, particularly in triple-negative (TN) and HER2-positive subtypes. However, the additional predictive value of morphological features of the inflammatory infiltrate beyond TIL quantification is not fully established. We aimed to assess the predictive value of TILs for response to NACT in breast cancer and to determine whether morphological characteristics of the inflammatory infiltrate enhance predictive accuracy. Methods: We analyzed 477 patients with stage II–III breast cancer treated with NACT between 2009 and 2016. Diagnostic core needle biopsies were prospectively re-evaluated. TILs were quantified according to International TILs Working Group recommendations. Morphological features of the infiltrate, including cell composition (lymphocytic vs. plasma cell-rich), heterogeneity, and localization, were evaluated using standardized criteria. Pathologic complete response (pCR) was defined as absence of invasive tumor in the breast and in the axillary lymph nodes (ypT0/Tis ypN0). Univariate and multivariate logistic regression analyses were performed to assess the predictive value of TILs (quantitative and morphological assessment) to achieve pCR for the entire cohort and by surrogate molecular subtype. Results: A TIL cutoff of >20% was identified as optimal for predicting pCR. High TILs were significantly associated with high-grade tumors, elevatedKi67, HER2-positive and TN subtypes, presence of plasma cells, and intraepithelial and heterogeneous infiltrates. In the overall cohort, TILs > 20% significantly increased the likelihood of pCR (OR 3.9, 95%IC 2.5–6.0, p < 0.001) and was an independent predictor of pCR. A combined variable incorporating TIL level and homogeneity improved predictive performance, with homogeneously high TILs emerging as a strong predictor of pCR (OR 5.521, 95%CI 3.174–9.603, p < 0.01). Plasma cell-rich and intraepithelial infiltrates were also associated with higher pCR rates (respectively, OR 2.7, 95%CI 1.5–5.0, p = 0.001 and OR 2.8, 95%CI 1.6–5.0, p < 0.001). Subtype-specific analyses confirmed the predictive value of TILs in TN tumors, but not in HER2-positive ones. Notably, in luminal B-like tumors, high TILs were the only independent predictor of response (OR 17.982, 95%CI 3.115–103.815, p = 0.001). Conclusions: TIL assessment on routine H&E-stained biopsies is a robust predictor of response to NACT in breast cancer that is readily available, cost-neutral and does not require additional techniques. Integration of simple morphological features significantly enhances predictive accuracy and may refine treatment stratification, particularly in luminal B-like tumors.