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Correlation Between Receptor Status and Presence of Axillary Lymph Node Metastasis in Breast Cancer in Kenya
Marilynn Omondi Akinyi, Kiptoon Dan, Ojuka Kinyuru Daniel, Walong Edwin
School of Medicine, University of Nairobi
Correspondence to: Dr. Marilynn Akinyi Omondi, Department of Surgery, University of Nairobi, PO Box 19676–00202, Nairobi;
email: marokinyi@gmail.com

 Abstract

Background: Breast cancer survival is linked to early detection, and timely and appropriate treatment. Survival depends on the stage and biological behaviour of the tumour. It is unclear how different molecular subtypes impact on axillary node involvement. Objective: This study sought to determine the correlation between hormonal receptor status with axillary nodal status in breast carcinoma. Methodology: A cross sectional study was carried out at Kenyatta National Hospital surgical wards and histopathology laboratory. Patients with a histological diagnosis of breast cancer, scheduled to undergo a modified radical mastectomy, were recruited. Data collected included age at diagnosis, parity, menopausal status, clinical examination findings, stage of the disease clinically and pathologically, and hormonal receptor status. Data were analyzed using SPSS version 21.0. Results: We enrolled 79 women with invasive breast carcinoma. Mean age was 48 (SD=14.5) years. Most (48.1%) presented with stage III tumour. Most tumours (58.2%) were luminal A. Correlation between molecular type and nodal involvement was not significant. Luminal B was significantly present in those above 50 years (p=0.011). Conclusion: The most common molecular type of breast cancer was luminal A, but luminal B disease which was prevalent in women more than 50 years old was the only molecular subtype that had a positive correlation with axillary nodal status.

Key words: Breast cancer, Axillary lymph nodes, Molecular subtypes, Hormonal receptor status, HER-2 status

Ann Afr Surg. 2019; 16(2):51–54

DOI:http://dx.doi.org/10.4314/aas.v16i2.2

Conflicts of Interest: None

Funding: None

© 2019 Author. This work is licensed under the Creative Commons Attribution 4.0 International License.

Introduction

Breast cancer growth, spread and management are hormone dependent. Guidelines written jointly by the American Society of Clinical Oncology and the College of American Pathologists recommend the routine analysis of oestrogen and progesterone receptors (ER/PR) in all breast cancers (1). This is because the presence of these receptors determines prognosis and selection of appropriate treatment. The success of hormonal therapies such as selective oestrogen receptor modulators and aromatase inhibitors is limited to patients whose cancers express ER/PR. Low grade tumours are more likely to be ER/PR positive and tend to have a better prognosis unlike those with a negative ER/PR status that tend to be larger, higher stage tumours with poorly differentiated morphology and an increased number of axillary lymph node metastases (2, 3).

Multifocal disease, high grade disease, large tumours and lymphovascular invasion have been described as predictors of axillary node metastasis, but the impact of tumour molecular subtype on axillary node involvement has not been correlated yet (4, 5).

Lymph node metastasis is the most important prognostic factor in patients with operable breast cancer. The number of positive lymph nodes correlates directly with local and distant recurrence. The five-year overall survival (OS) is 82.8% in lymph node negative disease but drops to 73% in patients with 1–3 positive lymph nodes, reducing further to 45.7% in patients with 4–12 positive nodes and to 28.4% in those with more than 13 positive lymph nodes (6, 7). Rates of axillary node involvement in the different molecular breast cancer subtypes based on their combined immunohistochemistry expression of hormonal receptors and human epidermal growth factor receptor 2 (HER-2) status have not been systematically described in our population, and controversies about the role of lymph node involvement as an intrinsic characteristic of breast cancer genetics remains (8).

This study sought to determine the correlation between molecular types of breast cancer and the axillary lymph node status.

 

Patients and Methods

A cross sectional study was conducted over 9 months at the surgical wards and histopathology laboratory of Kenyatta National Hospital. The study was carried out among consenting female patients 18 years and above with a histological diagnosis of breast cancer stages I–III scheduled to undergo modified radical mastectomy. We excluded those with previous history of lymph node dissection or those with neoadjuvant therapy and those with recurrent disease.

​Data collected included age at diagnosis, parity, menopausal status, clinical examination findings and stage of the disease, histopathologic findings including nodal status, hormonal receptor status and HER-2.

Following gross examination and selection of tissues for evaluation, the specimens were preserved for at least 6 hours in 10% neutral buffered formal saline, then processed for up to 8 hours to dehydrate the tissues and impregnate the cells with molten paraffin wax to prevent tissue degradation. The tissue section was then processed and stained with haematoxylin and eosin stain. [9] Immunohistochemistry was performed using tissue microarrays for hormonal receptor status and HER-2. This information was then used to classify invasive breast cancer into the different molecular subtypes described, which are luminal A(ER/PR + HER-2 –ve), luminal B(ER/PR +ve HER-2 +ve or -ve), HER-2 enriched (ER/PR –ve HER-2 +ve), basal like and triple negative disease (ER/PR –ve HER-2 –ve) (10).

Data were analyzed using SPSS version 21.0. Patient characteristics were summarized using age, parity and menopausal status; continuous data were presented as means and categorical variables as proportions. Prevalence of hormone receptor expression was presented as a proportion of all breast cancer patients. Axillary lymph node involvement was presented as a percentage and associated with hormone receptor status using chi-square test of associations. Odds ratios were calculated and presented as estimates for relative risk of axillary involvement in patients with hormone receptor expressions. The sample size was calculated to ensure that all statistical tests were conducted at 5% level of significance with a power of 80%. This study was approved by the Institutional Review Board of the University of Nairobi.

Results

The cross sectional study comprised 79 women with invasive breast cancer who underwent a modified radical mastectomy. Their mean age was 48 years (SD=14.5); most (54.4%) were in the age group 30–49 years (Figure 1).

Click to view Figure 1