Objectives: Locally advanced breast cancer (
LABC) poses a difficult clinical challenge with an overall poor long-term prognosis. The strength of the association between tumour characteristics, treatment response, and outcome is not well defined. In the present study, we attempted to gain further insight into
LABC by reviewing tumour characteristics of patients treated with neoadjuvant chemotherapy and by studying the association of those characteristics with outcome. We calculated the residual cancer burden (
RCB) score obtained at surgery and attempted to study its correlation with event-free survival (
EFS) and overall survival (
OS).
Methods: We studied patients diagnosed primarily with
LABC (
n = 45). Pathologic and clinical responses were determined. Pathology slides were reviewed.
Results: Of the 45 study patients, 9% had stage iib disease; 29%, stage
IIIA; 51%, stage
IIIB; and 11%, stage
IIIC. Inflammatory breast cancer (
IBC) was found in 16%. Pathologic complete response (p
CR) was achieved in 22% of all patients. None of the patients with
IBC achieved p
CR. Patients with estrogen receptor–negative (
ER−)/progesterone receptor–negative (
PR−) tumours were more likely to achieve p
CR than were those with
ER+/
PR+ tumours. Among patients with tumours that overexpressed human epidermal growth factor receptor 2 (
HER2/
neu), 17% achieved p
CR as compared with 25% of patients with non-overexpressing tumours; only 1 patient had received trastuzumab. The
RCB scores were calculated in 32 patients and ranged between 0 and 4.6.
Conclusions: The present study examined practical issues related to the classification and management of
LABC and
IBC. The
RCB, defined from routine pathology materials, was easily quantifiable. It appears to be a better predictor than p
CR of outcome following neoadjuvant chemotherapy in
LABC. Higher
RCB scores were associated with lower
EFS and a lower rate of
OS. A continual quest for reliable predictive and correlative prognostic markers, and for better surrogate endpoints for outcome, is essential to advance our understanding of
LABC and to improve treatment outcomes.
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