The Relevance of Breast Cancer Subtypes in the Outcome of Neoadjuvant Chemotherapy

• Published in: Annals of surgical oncology Vol. 17; no. 9; pp. 2411 - 2418
• Main Authors: Straver, M. E., Rutgers, E. J. Th, Rodenhuis, S., Linn, S. C., Loo, C. E., Wesseling, J., Russell, N. S., Oldenburg, H. S. A., Antonini, N., Vrancken Peeters, M. T. F. D.
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01-09-2010; Springer Nature B.V
• Subjects: Adenocarcinoma - drug therapy; Adenocarcinoma - metabolism; Adenocarcinoma - surgery; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - metabolism; Breast Neoplasms - surgery; Breast Oncology; Carcinoma, Ductal, Breast - drug therapy; Carcinoma, Ductal, Breast - metabolism; Carcinoma, Ductal, Breast - surgery; Carcinoma, Lobular - drug therapy; Carcinoma, Lobular - metabolism; Carcinoma, Lobular - surgery; Cyclophosphamide - administration & dosage; Docetaxel; Doxorubicin - administration & dosage; Female; Humans; Medicine; Medicine & Public Health; Middle Aged; Neoadjuvant Therapy; Neoplasm Invasiveness; Neoplasm Staging; Neoplasms, Hormone-Dependent - drug therapy; Neoplasms, Hormone-Dependent - metabolism; Oncology; Receptor, ErbB-2 - metabolism; Receptors, Estrogen - metabolism; Receptors, Progesterone - metabolism; Retrospective Studies; Surgery; Surgical Oncology; Taxoids - administration & dosage; Treatment Outcome; Young Adult; Invasive Lobular Carcinoma; Breast Cancer Subtype; Pathological Complete Response; Trastuzumab; Lobular Carcinoma
• ISSN: 1068-9265; 1534-4681
• DOI: 10.1245/s10434-010-1008-1

Background
Breast cancer is increasingly considered a heterogeneous disease. The aim of this study was to assess the differences between histological and receptor-based subtypes in breast-conserving surgery and pathological complete response (pCR) after neoadjuvant chemotherapy.
Method
A consecutive series of 254 patients with operable breast cancer treated with neoadjuvant chemotherapy was analyzed. Tumors were classified according to their receptor status in estrogen receptor (ER)-positive tumors (HER2-negative), triple-negative tumors, and HER2-positive tumors. The type of surgery feasible prior to neoadjuvant chemotherapy was compared with the actual surgery performed.
Results
The overall increase in breast-conserving surgery was 37% (73 of 198). In patients with ductal and lobular carcinomas this increase was 41% (63 of 152, 95% confidence interval [95% CI] 0.34–0.49) and 20% (7 of 35, 95% CI 0.10–0.36), respectively (
P
 = 0.02). Half of the patients with lobular carcinoma had to undergo a secondary mastectomy because of incomplete resection margins. In ER-positive, triple-negative and HER2-positive tumors, the increase in breast-conserving surgery was 39% (42 of 109, 95% CI 0.30–0.48), 24% (11 of 45, 95% CI 0.14–0.38), and 45% (20 of 44, 95% CI 0.32–0.60) (
P
 = 0.11). The pCR rate in ductal and lobular carcinomas was 12% (23 of 195) and 2% (1 of 42), respectively (
P
 = 0.09). In ER-positive, triple-negative and HER2-positive tumors the pCR rates were 2% (3 of 138), 28% (16 of 57), and 18% (10 of 56), respectively. Multivariate analysis showed that the receptor-based subtype was the only significant predictor of pCR (
P
 = 0.004).
Conclusion
In lobular tumors the benefit with regard to breast-conserving surgery of neoadjuvant chemotherapy is questionable. Although in ER-positive tumors the pCR rate is low, the increase in breast-conserving surgery was remarkable in ductal ER-positive tumors.