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.

Introduction: Five to 10% of breast cancers (BCs) occur in a genetic predisposition context (mainly BRCA pathogenic variant). Nevertheless, little is known about immune tumor infiltration, response to neoadjuvant chemotherapy (NAC), pathologic complete response (pCR) and adverse events according to BRCA status. Material and Methods: Out of 1199 invasive BC patients treated with NAC between 2002 and 2012, we identified 267 patients tested for a germline BRCA pathogenic variant. We evaluated pre-NAC and post-NAC immune infiltration (TILs). Response to chemotherapy was assessed by pCR rates. Association of clinical and pathological factors with TILs, pCR and survival was assessed by univariate and multivariate analyses. Results: Among 1199 BC patients: 46 were BRCA-deficient and 221 BRCA-proficient or wild type (WT). At NAC completion, pCR was observed in 84/266 (31%) patients and pCR rates were significantly higher in BRCA-deficient BC (p = 0.001), and this association remained statistically significant only in the luminal BC subtype (p = 0.006). The interaction test between BC subtype and BRCA status was nearly significant (Pinteraction = 0.056). Pre and post-NAC TILs were not significantly different between BRCA-deficient and BRCA-proficient carriers; however, in the luminal BC group, post-NAC TILs were significantly higher in BRCA-deficient BC. Survival analysis were not different between BRCA-carriers and non-carriers. Conclusions: BRCA mutation status is associated with higher pCR rates and post-NAC TILs in patients with luminal BC. BRCA-carriers with luminal BCs may represent a subset of patients deriving higher benefit from NAC. Second line therapies, including immunotherapy after NAC, could be of interest in non-responders to NAC.

Introduction: Five to 10% of breast cancers (BCs) occur in a genetic predisposition context (mainly BRCA pathogenic variant). Nevertheless, little is known about immune tumor infiltration, response to neoadjuvant chemotherapy (NAC), pathologic complete response (pCR) and adverse events according to BRCA status. Material and methods: Out of 1199 invasive BC patients treated with NAC between 2002 and 2012, we identified 267 patients tested for a germline BRCA pathogenic variant. We evaluated pre-NAC and post-NAC immune infiltration (TILs). Response to chemotherapy was assessed by pCR rates. Association of clinical and pathological factors with TILs, pCR and survival was assessed by univariate and multivariate analyses. Results: Among 1199 BC patients: 46 were BRCA-deficient and 221 BRCA-proficient or wild type (WT). At NAC completion, pCR was observed in 84/266 (31%) patients and pCR rates were significantly higher in BRCA-deficient BC (p= 0.001), and this association remained statistically significant only in the luminal BC subtype (p= 0.006). The interaction test between BC subtype and BRCA status was nearly significant (Pinteraction=0.056). Pre and post-NAC TILs were not significantly different between BRCA-deficient and BRCA-proficient carriers; however, in the luminal BC group, post-NAC TILs were significantly higher in BRCA-deficient BC. Survival analysis were not different between BRCA-carriers and non-carriers. Conclusion: BRCA mutation status is associated with higher pCR rates and post-NAC TILs in patients with luminal BC. BRCA-carriers with luminal BCs may represent a subset of patients deriving higher benefit from NAC. Second line therapies, including immunotherapy after NAC, could be of interest in non-responders to NAC.

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 T1T3NxM0 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 RCB0 patients displayed similar prognosis when compared to the RCBI group, while patients from the RCBII and RCBIII classes were at increased risk of relapse (RCBII versus RCB0: HR=3.25 CI [2.1;5.1] p < 0.001; RCBIII versus RCB0: HR=5.6 CI [3.5;8.9] p < 0.001). The prognostic impact of RCB index was significant for TNBC and HER2 positive cancers; but not for luminal cancers (Pinteraction = 0.07). The prognosis of RCBIII patients was poor (8 years RFS: 52.7%, 95% CI [44.8 ; 62.0]) particularly in the TNBC subgroup, where the median RFS was 12.7 months. Conclusion: RCB index is a reliable prognostic score. RCB accurately identifies patients at a high risk of recurrence (RCBIII) with TNBC or HER2 positive BC who must be offered second-line adjuvant therapies.

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