Date of Award
3-2023
Document Type
Dissertation
Degree Name
Master of Medicine (MMed)
First Supervisor/Advisor
Athar Ali
Second Supervisor/Advisor
Caroline Ngimba
Third Supervisor/Advisor
Philip Adebayo
Department
General Surgery (East Africa)
Abstract
Background:
Breast cancer immunohistochemistry is a biological characteristic of the tumour which has a role to diagnose molecular subtype, prognosticate and guide treatment and categorised into 4 subtypes, Luminal A, Luminal B, Human Epidermal Growth Factor Receptor 2 (HER2) enriched and Triple Negative Breast Cancer (TNBC).
Objectives:
To determine the prevalence of each molecular subtype of breast cancer and determine their association with pathological and demographic characteristics.
Methods:
A retrospective cross-sectional study was carried out at two tertiary referral hospitals on participants who were recruited from the cancer registries from 2015-2022 and had a breast tissue biopsy confirming primary breast cancer and undergone further immunohistochemistry analysis. Prevalence of each subtype was determined and association between molecular subtype to demographic and pathological characteristics were evaluated. Predictors of molecular subtypes was then determined using logistic regression. A level of statistical significance was determined at p-value of <0.05 Results: Total number of participants were 1214, median age was 50 (IQR: 41-61), median tumour size was 5cm (IQR: 4-7) with lymph node positivity in 73.7%. Immunohistochemistry studies showed estrogen, progesterone and HER2 receptor positivity in 54.4%, 34.4% and 27.8% of cases respectively. Molecular subtype classification prevalence for Luminal A was 21.17% (95% CI: 18.87-23.47), for Luminal B 35.75% (95% CI: 33.05-38.45), for HER2 enriched 11.86% (95% CI: 10.04-13.68) and for TNBC 31.22% (95% CI: 28.61-33.83). Significant association was seen between molecular subtype with age, tumour size, tumour grade and lymph node involvement. Predictors of Luminal tumours were larger tumour size (aOR 1.217, 95% CI: 1.149-1.291) no lymph node involvement (aOR 0.429, 95% CI: 0.313-0.589) while an advanced tumour grade reduced likelihood (aOR 0.041, 95% CI: 0.011-0.019).
Conclusion: In Tanzania Luminal B was most predominant subtype presenting at an earlier age and associated with more favourable pathological characteristics.
Recommendations:
We encourage the routine use of IHC on all patients with breast cancer as it has a role in diagnosis, prognosis and treatment.
Recommended Citation
ISMAIL, A. (2023). Breast cancer molecular subtype classification according to immunohistochemistry markers and its association with pathological characteristics among women attending tertiary hospitals in Tanzania. (Unpublished master's dissertation). Aga Khan University, East Africa.