Subtypes of Breast Cancer in Lao P.D.R.: A Study in a Limited-Resource Setting

Document Type: Research Articles

Authors

1 Department of Comprehensive Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.

2 Cancer Center, Mittaphab Hospital, Vientiane, Laos.

3 Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University (TMDU, Tokyo, Japan.

4 Department of Clinical Laboratory Sciences, Sanyo Women's College, Hiroshima, Japan.

5 Department of Pathology, University of Health Sciences, Vientiane, Laos.

6 Department of Gynecology-Obstetrics, Setthathirath Hospital, Vientiane, Laos. 

7 Center for Information, Jichi Medical University, Shimotsuke, Japan.

8 Department of Pathology, School of Medicine, Toho University,Tokyo, Japan.

9 Department of Molecular Pathology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.

Abstract

Aim: The purpose of this study is to evaluate the prevalence of the immunohistochemical subtypes of breast cancer
among Lao women by using immunohistochemistry (according to the St. Gallen 2017 guidelines) and to study their
correlation to clinicopathological features in order to help guide better treatment plans for patients. Materials and
methods: Formalin-fixed and paraffin embedded tissue blocks of 76 cases of primary invasive breast cancer were
retrieved from the University of Health Sciences, Vientiane, Lao PDR, from 2013 to 2016. Patients’ information and
previous histological reports were reviewed. Immunohistochemistry was done using antibodies against estrogen receptor
(ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2/neu) and Ki-67 (MIB-1). Results:
The mean age of the patients was 49 years, and the major histologic type was invasive ductal carcinoma, NOS (90.7%).
The proportion of each subtype was hormone receptor-positive and HER2-negative, 44.7%; hormone receptor-positive
and HER2-positive, 3.9%; hormone receptor-negative and HER2-positive, 13.2%; and triple-negative, 38.2%. ER was
positive in 40.8% of the cases, while PR was positive in 47.4%. More than half of the cases were poorly differentiated
cancer (65.8%), followed by moderately differentiated (34.2%). Tumors presented with pT2 (60.5%), followed by pT3
(25.0%) and pT4 (7.9%). Conclusion: Breast cancer among Lao women is characterized by a large percentage of the
triple-negative subtype that is less susceptible to hormonal treatments. The empirical treatment with tamoxifen should
be reconsidered since it would be less effective to these patients. More importantly, basic pathology services should
be the first requirement in Lao PDR in order to provide adequate care.

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