Aims To correlate the ‘Residual Cancer Burden’ (RCB) index with overall survival (OS) and disease-free survival (DFS) in women undergoing neoadjuvant chemotherapy at the Cancer Institute of the State of São Paulo.
Methods We analysed the medical records of patients with breast cancer who underwent neoadjuvant chemotherapy and breast surgery, from 2011 to December 2017. Variables analysed were age, clinical and pathological staging, molecular subtype, number of recurrences or metastases, number of deaths, value and class of the RCB index. We used the Kaplan-Meier and the log-rank statistics to evaluate the possible association between RCB and OS and DFS. A regression model was used to determine the independent association of the RCB with the outcomes controlling for confounding factors.
Results 347 patients were included in the analysis with a mean age of 49.39 years. Initial clinical staging was T3 in 57.9% of patients and 43.8% of patients had N1 axillary status. Survival analysis showed a statistically significant better prognosis for the RCB 0 (pCR) subgroup compared with RCB 1, 2 and 3 (log rank p=0.01). In a multivariate analysis, only the RCB classification showed a statistically significant correlation with DFS (RCB 1, HR 6.9, CI 1.9 to 25.4, p=0.004; RCB 2, HR 4.2, CI 1.6 to 10.8, p=0.03; and RCB 3, HR 7.6, CI 2.76 to 20.8, p=0.00).
Conclusion We demonstrated a positive and significant relationship between the RCB index and the risk of relapse and death.
Data availability statement
Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as online supplemental information.
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Handling editor Cheok Soon Lee.
Contributors JPGdC and RG participated in the conception and design of the work. JPGdC, RG, FNA and BBC participated in the data collection. JPGdC, RG, FS, FNA, BSM, BBC, JMS, ECB and JRF participated in the data analysis and interpretation. JPGdC and RG drafted the article. JPGdC, RG, FS, FNA, BSM, BBC, JMS, ECB and JRF critically reviewed the article. JPGdC, RG, FS, FNA, BSM, BBC, JMS, ECB and JRF approved the final version to be published.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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