Biomarker Dynamics and Long-Term Treatment Outcomes in Breast Cancer Patients with Residual Cancer Burden after Neoadjuvant Therapy.

A residual cancer burden after neoadjuvant therapy (NAT) for breast cancer (BC) is associated with worse treatment outcomes compared to patients who achieved pathologic complete remission. This single-institutional retrospective study of 767 consecutive patients, including 468 patients with assessable residual cancer burden (aRCB) after NAT, with a median follow-up of 36 months, evaluated the biomarkers assessed before NAT from a biopsy and after NAT from a surgical specimen, their dynamics, and effect on long-term outcomes in specific breast cancer subtypes. The leading focus was on proliferation index Ki-67, which was significantly altered by NAT in all BC subtypes (p < 0.001 for HER2 positive and luminal A/B HER2 negative and p = 0.001 for TNBC). Multivariable analysis showed pre-NAT and post-NAT Ki-67 as independent predictors of survival outcomes for luminal A/B HER2 negative subtype. For TNBC, post-NAT Ki-67 was significant alone, and, for HER2 positive, the only borderline association of pre-NAT Ki-67 was observed in relation to the overall survival. Steroid and HER2 receptors were re-assessed just in a portion of the patients with aRCB. The concordance of both assessments was 92.9% for ER status, 80.1% for PR, and 92.2% for HER2. In conclusion, these real-world data of a consecutive cohort confirmed the importance of biomarkers assessment in patients with aRCB, and the need to consider specific BC subtypes when interpreting their influence on prognosis.

Neoadjuvant Chemotherapy of Triple-Negative Breast Cancer: Evaluation of Early Clinical Response, Pathological Complete Response Rates, and Addition of Platinum Salts Benefit Based on Real-World Evidence.

Pathological complete response (pCR) achievement is undoubtedly the essential goal of neoadjuvant therapy for breast cancer, directly affecting survival endpoints. This retrospective study of 237 triple-negative breast cancer (TNBC) patients with a median follow-up of 36 months evaluated the role of adding platinum salts into standard neoadjuvant chemotherapy (NACT). After the initial four standard NACT cycles, early clinical response (ECR) was assessed and used to identify tumors and patients generally sensitive to NACT. BRCA1/2 mutation, smaller unifocal tumors, and Ki-67 ≥ 65% were independent predictors of ECR. The total pCR rate was 41%, the achievement of pCR was strongly associated with ECR (OR = 15.1, p < 0.001). According to multivariable analysis, the significant benefit of platinum NACT was observed in early responders ≥45 years, Ki-67 ≥ 65% and persisted lymph node involvement regardless of BRCA1/2 status. Early responders with pCR had a longer time to death (HR = 0.28, p < 0.001) and relapse (HR = 0.26, p < 0.001). The pCR was achieved in only 7% of non-responders. However, platinum salts favored non-responders' survival outcomes without statistical significance. Toxicity was significantly often observed in patients with platinum NACT (p = 0.003) but not for grade 3/4 (p = 0.155). These results based on real-world evidence point to the usability of ECR in NACT management, especially focusing on the benefit of platinum salts.

Effectiveness of Neoadjuvant Therapy with Platinum-Based Agents for Patients with BRCA1 and BRCA2 Germline Mutations - A Retrospective Analysis of Breast Cancer Patients Treated at MMCI Brno.

BACKGROUND: Mutations in the BRCA1 and BRCA2 genes are associated with a high risk of developing breast cancer. Tumors arising from this mutation are expected to be more sensitive to platinum-based drugs. The role of platinum-based drugs in systemic neoadjuvant BRCA1/2 breast cancer therapy, and its efficacy in increasing the probability of pathological complete remission (pCR) are discussed repeatedly; however, there are no clear recommendations. PATIENTS AND METHODS: We retrospectively evaluated the contribution of a platinum-based antineoplastic drug to the achievement of pCR in a set of patients with BRCA1/2 mutant breast cancer treated with neoadjuvant chemotherapy from 2010 to 2017. The response to neoadjuvant chemotherapy was evaluated by a pathologist using definitive surgical specimens. A pCR was defined as a condition in which complete invasive breast cancer, and (eventually) positive lymph nodes, had disappeared. RESULTS: Of 76 patients (median age, 39 years; 62% with triple negative breast cancer (TNBC); 70% with BRCA1 positivity), 37 were treated with platinum-based drugs. More patients treated with platinum derivatives achieved pCR (57% vs. 23%, p = 0.005). Patients treated in a neoadjuvant setting with platinum-based antineoplastic drugs had a 4.4× greater chance of achieving pCR than those not treated with platinum, assuming the same tumor phenotype (TNBC or SR+/HER2). CONCLUSION: Neoadjuvant platinum-based chemotherapy for patients with a BRCA1/2 mutation is associated with a higher probability of achieving pCR, which is important for subsequent prognosis. This treatment should be considered particularly for patients with BRCA1 mutation and a TNBC phenotype. This work was supported by grant of the Ministry of Health of the Czech Republic - Conceptual. Development of a Reaserch Organization (MMCI 00209805). This work was supported by grant of the Ministry of Education, Youth and Sport of the Czech Republic (NPU I - LO1413). The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 21. 3. 2019 Accepted: 14. 5. 2019.