TITLE:
Correlation between Cancer Breast Subtypes and Age at Presentation in Egyptian Patients; Single Institution Experience
AUTHORS:
Azza M. Adel, Dalia Abdelghani
KEYWORDS:
Breast Cancer, Molecular Subtypes, Egyptian, Age
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.11 No.1,
January
16,
2020
ABSTRACT: Background: Breast cancer is defined according to molecular subtypes. Each molecular
subtype defines different disease behavior and requires different treatment. The different molecular subtypes have
different risk factors and different distribution across age classes. Aim of the study: To detect the incidence of cancer breast subtypes by age among Egyptian
patients treated at the Clinical Oncology Department, Faculty of Medicine, Ain
Shams University, in the period between
April 2016 and December 2018. Patients and Methods: Inclusion criteria: Cases with proven
pathological diagnosis and underwent IHC studies for the molecular
subtype while exclusion criteria were: Bilateral cases, cases with unknown
molecular subtype or age at presentation, cases with multiple primaries, cases
with in situ cancer, male breast cancer cases, and cases diagnosed during pregnancy. Age classes were computed in four
groups: from 20 - 35, >35 - 50, >50 - 65 and those older than 65 years of age. Immunohistochemical studies were
done; ER, PR and HER2 were recorded for
each case, Molecular subtypes were defined as follows: HR+/HER2-, HR+/HER2+, HER2 overexpressed (HER2
positive, HR-) and Triple
Negative Breast Cancer; TNBC
(HER2 negative, ER negative and PR negative). Results: one thousand and two cases were included in the study. The median age was
51 years and the mean age was 51.64 ± 11.74, with range from 24 to 85 years.
The total number of ER positive patients was 706 patients (70.5%), the total
number of PR positive patients was 667 (66.6%), and the total number of Her2
positive patients was 286 patients (28.5%). While there were no statistically
significant differences in the incidence of ER and PR positivity among all
age classes, Her2 over expression decreased with age and the
difference was statistically significant (P-value: 0.012). Her2 overexpression
subtype incidence decreased by age and it was highest in the younger age group
17.6% compared to 8.2% in the older age group and the difference was
statistically significant. Similarly, HR+/HER2-tumors incidence were higher in patients older than
65 (57.4%) and lower in the younger age group (40.5%) (P-value: 0.031). Triple
negative tumors incidence ranged from 14.9%
for those younger than 35 to 17.2% for those older than 65 years. Conclusion: This study shows that there are significant differences in the age distribution by molecular subtype and the
incidence of Her2 overexpression subtype decreases by age. The study also shows that
the nature of the breast cancer in the group of Egyptian patients studied is
more of the favorable hormonal positive subtype.