Open AccessPrognostic value of the Residual Cancer Burden index according to breast cancer subtype: Validation on a cohort of BC patients treated by neoadjuvant chemotherapy
Author(s) -
Anne-Sophie Hamy,
Lauren Darrigues,
Enora Laas,
Diane De Croze,
Lucian Topciu,
Giang-Thanh Lam,
Clémence Evrevin,
Sonia Rozette,
Lucie Laot,
Florence Lerebours,
JeanYves Pierga,
Marie Osdoit,
Matthieu Faron,
Jean-Guillaume Féron,
Marick Laé,
Fabien Reyal
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0234191
Subject(s) - medicine , cohort , oncology , breast cancer , chemotherapy , cancer , population , triple negative breast cancer , environmental health
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 <0.001; RCB-III versus RCB-0: 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 ( P interaction = 0.07). The prognosis of RCB-III 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 (RCB-III) with TNBC or HER2 -positive BC who must be offered second-line adjuvant therapies.