Background Previous studies have independently validated the prognostic relevance of residual cancer burden (RCB) after neoadjuvant chemotherapy. We used results from several independent cohorts in a pooled patient-level analysis to evaluate the relationship of RCB with long-term prognosis across different phenotypic subtypes of breast cancer, to assess generalisability in a broad range of practice settings. MethodsIn this pooled analysis, 12 institutes and trials in Europe and the USA were identified by personal communications with site investigators. We obtained participant-level RCB results, and data on clinical and pathological stage, tumour subtype and grade, and treatment and follow-up in November, 2019, from patients (aged ≥18 years) with primary stage I-III breast cancer treated with neoadjuvant chemotherapy followed by surgery. We assessed the association between the continuous RCB score and the primary study outcome, event-free survival, using mixed-effects Cox models with the incorporation of random RCB and cohort effects to account for betweenstudy heterogeneity, and stratification to account for differences in baseline hazard across cancer subtypes defined by hormone receptor status and HER2 status. The association was further evaluated within each breast cancer subtype in multivariable analyses incorporating random RCB and cohort effects and adjustments for age and pretreatment clinical T category, nodal status, and tumour grade. Kaplan-Meier estimates of event-free survival at 3, 5, and 10 years were computed for each RCB class within each subtype. FindingsWe analysed participant-level data from 5161 patients treated with neoadjuvant chemotherapy between Sept 12, 1994, and Feb 11, 2019. Median age was 49 years (IQR 20-80). 1164 event-free survival events occurred during follow-up (median follow-up 56 months [IQR 0-186]). RCB score was prognostic within each breast cancer subtype, with higher RCB score significantly associated with worse event-free survival. The univariable hazard ratio (HR) associated with one unit increase in RCB ranged from 1•55 (95% CI 1•41-1•71) for hormone receptor-positive, HER2-negative patients to 2•16 (1•79-2•61) for the hormone receptor-negative, HER2-positive group (with or without HER2-targeted therapy; p<0•0001 for all subtypes). RCB score remained prognostic for eventfree survival in multivariable models adjusted for age, grade, T category, and nodal status at baseline: the adjusted HR ranged from 1•52 (1•36-1•69) in the hormone receptor-positive, HER2-negative group to 2•09 (1•73-2•53) in the hormone receptor-negative, HER2-positive group (p<0•0001 for all subtypes).Interpretation RCB score and class were independently prognostic in all subtypes of breast cancer, and generalisable to multiple practice settings. Although variability in hormone receptor subtype definitions and treatment across patients are likely to affect prognostic performance, the association we observed between RCB and a patient's residual risk suggests that prospective evaluation of RCB could be c...

Purpose: High levels of tumor-infiltrating lymphocytes (TIL) before neoadjuvant chemotherapy (NAC) are associated with higher pathologic complete response (pCR) rates and better survival in triple-negative breast cancer (TNBC) and HER2-positive breast cancer. We investigated the value of TIL levels by evaluating lymphocyte infiltration before and after NAC.Experimental Design: We assessed stromal TIL levels in 716 pre-and posttreatment matched paired specimens, according to the guidelines of the International TIL Working Group.Results: Pre-NAC TIL levels were higher in tumors for which pCR was achieved than in cases with residual disease (33.9% vs. 20.3%, P ¼ 0.001). This was observed in luminal tumors and TNBCs, but not in HER2-positive breast cancers (P Interaction ¼ 0.001). The association between pre-NAC TIL levels and pCR was nonlinear in TNBCs (P ¼ 0.005). Mean TIL levels decreased after chemotherapy completion (pre-NAC TILs: 24.1% vs. post-NAC TILs: 13.0%, P < 0.001). This decrease was strongly associated with high pCR rates, and the variation of TIL levels was strongly inversely correlated with pre-NAC TIL levels (r ¼ À0.80, P < 0.001). Pre-NAC TILs and disease-free survival (DFS) were associated in a nonlinear manner (P < 0.001). High post-NAC TIL levels were associated with aggressive tumor characteristics and with impaired DFS in HER2-positive breast cancers (HR, 1.04; confidence interval, 1.02-1.06; P ¼ 0.001), but not in luminal tumors or TNBCs (P Interaction ¼ 0.04).Conclusions: The associations of pre-and post-NAC TIL levels with response to treatment and DFS differ between breast cancer subtypes. The characterization of immune subpopulations may improve our understanding of the complex interactions between pre-or post-NAC setting, breast cancer subtype, response to treatment, and prognosis.

Introduction The Residual Cancer Burden (RCB) quantifies residual disease after neoadjuvant chemotherapy (NAC). Its predictive value has not been validated on large cohorts with long-term follow up. The objective of this work is to independently evaluate the prognostic value of the RCB index depending on BC subtypes (Luminal, HER2-positive and triple negative (TNBCs)). Methods We retrospectively evaluated the RCB index on surgical specimens from a cohort of T1-T3NxM0 BC patients treated with NAC between 2002 and 2012. We analyzed the association between RCB index and relapse-free survival (RFS), overall survival (OS) among the global population, after stratification by BC subtypes. Results 717 patients were included (luminal BC (n = 222, 31%), TNBC (n = 319, 44.5%), HER2-positive (n = 176, 24.5%)). After a median follow-up of 99.9 months, RCB index was significantly associated with RFS. The RCB-0 patients displayed similar prognosis when compared to the RCB-I group, while patients from the RCB-II and RCB-III classes were at increased risk of relapse (RCB-II versus RCB-0: HR = 3.25 CI [2.1-5.1] p<0.

Abstract Background High levels of stromal tumor infiltrating lymphocytes (sTIL) are associated with increased pathological complete response (pCR) rate and longer survival after neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) patients. Here, we evaluated the value of sTIL in predicting pCR and explored prognosis in TNBC patients treated with neoadjuvant chemotherapy according to body mass index (BMI). Methods sTIL were scored centrally on pre-treatment biopsies from two retrospective series of non-underweight TNBC patients (n = 445). sTIL and BMI were considered as binary (sTIL: &lt;30.0% versus ≥30.0%, BMI: lean versus overweight and obese) and continuous variables. Associations with pCR (ypT0/isN0) were assessed using logistic regression, and associations with event-free (EFS) and overall survival (OS) using Cox regressions. Results 236 (53.0%) patients were lean and 209 (47.0%) overweight and obese. pCR was achieved in 181/445 (41.7%) patients. Median sTIL was 11.0% and 99/445 (22.2%) tumors had high sTIL. A statistically significant interaction between sTIL and BMI, considered as categorical or continuous variables, for predicting pCR was observed in the multivariable analysis (p=.03 and .04, respectively). High sTIL were statistically significantly associated with pCR in lean (odds ratio, OR = 4.24, 95%CI = 2.10-8.56, p&lt;.001), but not in heavier patients (OR = 1.48, 95%CI = 0.75-2.91, p=.26) in the multivariable analysis. High sTIL were further associated with increased EFS in lean (hazard ratio, HR = 0.22, 95%CI = 0.08-0.62, p=.004), but not in heavier patients (HR = 0.53, 95%CI = 0.26-1.08, p=.08). Similar results were obtained for OS. Conclusion BMI is modifying the effect of sTIL on pCR and prognosis in TNBC patients treated with neoadjuvant chemotherapy.

Background To compare RCB (Residual Cancer Burden) and Neo-Bioscore in terms of prognostic performance and see if adding pathological variables improve these scores. Methods We analysed 750 female patients with invasive breast cancer (BC) treated with neoadjuvant chemotherapy (NAC) at Institut Curie between 2002 and 2012. Scores were compared in global population and by BC subtype using Akaike information criterion (AIC), C-Index (concordance index), calibration curves and after adding lymphovascular invasion (LVI) and pre-/post-NAC TILs levels. Results RCB and Neo-Bioscore were significantly associated to disease-free and overall survival in global population and for triple-negative BC. RCB had the lowest AICs in every BC subtype, corresponding to a better prognostic performance. In global population, C-Index values were poor for RCB (0.66; CI [0.61–0.71]) and fair for Neo-Bioscore (0.70; CI [0.65–0.75]). Scores were well calibrated in global population, but RCB yielded better prognostic performances in each BC subtype. Concordance between the two scores was poor. Adding LVI and TILs improved the performance of both scores. Conclusions Although RCB and Neo-Bioscore had similar prognostic performances, RCB showed better performance in BC subtypes, especially in luminal and TNBC. By generating fewer prognostic categories, RCB enables an easier use in everyday clinical practice.