Response to neoadjuvant chemotherapy based on pathologic complete response in very young patients with ER-positive breast cancer: a large, multicenter, observational study.

Abstract

BACKGROUND:

In estrogen receptor (ER)-positive breast cancer (BC), young age is associated with poor prognosis. While very young patients respond better to chemotherapy, chemotherapy is less effective in ER-positive tumors than in ER-negative tumors. The authors tried to evaluate chemotherapy response of very young patients with ER-positive BC by pathologic complete response (pCR) after neoadjuvant chemotherapy excluding the effect of endocrine treatment to the extent possible.

METHODS:

We collected individual patient data from 1992 to 2013 from the Korean Breast Cancer Society (KBCS). Total 1048 ER-positive and 797 ER-negative patients aged < 50 years who had been treated with neoadjuvant chemotherapy were included for analysis. We compared pCR rate between patients aged < 35 years with ER-positive tumors and the other groups.

RESULTS:

The proportion of patients aged < 35 years was 14.0% of patients with ER-positive BC in this cohort of under 50 years old, and 16.8% of patients with ER-negative BC in this cohort of under 50 years old. Although most characteristics of tumors according to age were comparable, tumors with high Ki-67 expression were more common in patients aged < 35 years than in patients aged 35-49 years in both ER-positive and -negative group (P = 0.001). Breast conservation rates were not significantly different according to age (44.2% vs. 46.8% in ER-positive group, 55.2% vs. 48.0% in ER-negative group). pCR rate was not different according to age in ER-positive group (P = 0.71) but significantly better in patients aged < 35 years in ER-negative group (P = 0.009). After adjusting for confounding variables, young patients maintained the higher probability of pCR than older patients in ER-negative tumors. However, pCR rate did not differ according to age in ER-positive tumors. In multivariate analysis, young age (< 35 years) was correlated with poor overall survival (P = 0.003, HR = 1.98) and there was only one event in a few patients achieved pCR in ER-positive group.

CONCLUSIONS:

Chemotherapy response based on pCR was not better in young patients (< 35 years) with ER-positive BC than in older premenopausal patients with non-metastatic ER-positive BC. Young age cannot be a predictive factor of response to neoadjuvant chemotherapy in ER-positive BC. Different biological characteristics such as high proliferative index should be considered.

TRIAL REGISTRATION:

Retrospectively registered.

• Authors: Joohyun Woo, Se Jeong Oh, Jeong-Yoon Song, Byung Joo Chae, Jung Eun Choi, Jeeyeon Lee, Heung Kyu Park, Korean Breast Cancer Society, Woosung Lim
• Journal: BMC cancer (BMC Cancer) Vol. 21 Issue 1 Pg. 647 (May 31 2021) ISSN: 1471-2407 [Electronic] England
• PMID: 34059020 (Publication Type: Journal Article, Multicenter Study, Observational Study)

Chemical References

• Biomarkers, Tumor
• Receptors, Estrogen

Topics

• Adult
• Age Factors
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Biomarkers, Tumor (analysis, metabolism)
• Breast (pathology, surgery)
• Breast Neoplasms (mortality, pathology, therapy)
• Female
• Humans
• Kaplan-Meier Estimate
• Mastectomy
• Middle Aged
• Neoadjuvant Therapy (methods, statistics & numerical data)
• Prognosis
• Receptors, Estrogen (analysis, metabolism)
• Treatment Outcome