Breast Cancer Risk factors in Relation to Molecular Subtypes in Breast Cancer Patients from Kenya.

Abstract

BackgroundFew studies have investigated risk factor heterogeneity by molecular subtypes in indigenous African populations where prevalence of traditional breast cancer (BC) risk factors, genetic background, and environmental exposures show marked differences compared to European ancestry populations. MethodsWe conducted a case-only analysis of 838 pathologically confirmed BC cases recruited from 5 groups of public, faith-based and private institutions across Kenya between March 2012 to May 2015. Centralized pathology review and immunohistochemistry (IHC) for key markers (ER, PR, HER2, EGFR, CK5-6, and Ki67) was performed to define subtypes. Risk factor data was collected at time of diagnosis through a questionnaire. Multivariable polytomous logistic regression models were used to determine associations between BC risk factors and tumor molecular subtypes, adjusted for clinical characteristics and risk factors.ResultsThe median age at menarche and first pregnancy were 14 and 21 years, median number of children was 3 and breastfeeding duration was 62 months per child. Distribution of molecular subtypes for luminal A, luminal B, HER2-enriched, and Triple Negative (TN) breast cancers was 34.8%, 35.8%, 10.7%, and 18.6%, respectively. After adjusting for covariates, compared to patients with ER positive tumors, ER negative patients were more likely to have higher parity (OR=2.03, 95% CI= (1.11, 3.72), p=0.021, comparing ≥5 to <2 children) and younger age at first pregnancy (ORtrend=0.77, 95% CItrend=0.61, 0.98, Ptrend=0.032, comparing older to younger age). Compared to patients with luminal A tumors, luminal B patients were more likely to have lower parity (OR=0.45, 95% CI= 0.23, 0.87, p=0.018, comparing ≥5 to <2 children); HER2-enriched patients were less likely to be obese (OR=0.36, 95% CI=0.16, 0.81, p=0.013) or older age at menopause (OR=0.38, 95% CI=0.15, 0.997, p=0.049). Body mass index (BMI), either overall or by menopausal status, did not vary significantly by ER status. Overall, cumulative or average breastfeeding duration did not vary significantly across subtypes. Conclusions In Kenya, we found associations between parity-related risk factors and ER status consistent with observations in European ancestry populations, but differing associations with BMI and breastfeeding. Inclusion of diverse populations in cancer etiology studies are needed to develop population and subtype specific risk prediction/prevention strategies.

Factors Influencing the Uptake of Breast Cancer Screening Services among Women of Reproductive Age: A Case Study of Turbo Sub-county, Kenya

“…All WRA in Turbo sub-county were targeted because the increased risk of BC has been associated with changes in reproductive patterns including a shorter period of breastfeeding and low parity [14]. Additionally, Sayed et al, found out that among the diagnosed cases of BC in Kenya, almost 16 were aged below 25 years indicating the need for further research in this understudied age category [15].…”

“…In 2020, Kenya had a 5-year prevalence of BC of 57.28 per 100 000 (15,496) leading to 23% of all cancer cases [1]. In the same year, 6,799 (16.1%) new cases of BC were diagnosed and 3,107 (11.5%) deaths due to BC recorded [6].…”

To assess the knowledge regarding risk factors and preventive measures of carcinoma breast among Indian women: A comparative study

“…5,6 Acrosssectional study and the meta-analytical procedure were used to assess the risk factors and preventive measures regarding the carcinoma breast. [7][8][9] A case control study was conducted in Saudi Arabia on breast cancer survivors' perceptions of prevention versus control of future cancer recurrence. 10 Most of research on carcinoma breast were followed the cross-sectional study and use of structured questionnaire to assess the knowledge of risk factors and preventive measures of carcinoma breast.…”

Estrogen receptor negative breast cancer incidence rates are similar in Ghanaian and Non-Hispanic Black women in the USA

“…Given that both parity and breastfeeding are higher in Ghana compared to the US, it is unclear if these factors could contribute to differences in ERN rates across countries [17]. Whether biological, behavioural or social/environmental factors contribute to higher incidence rates of ERN tumours in women of SSA origins requires further investigation [1, 18], especially since data support different distributions of breast cancer subtypes in Kenya [19], South Africa [20] compared to Ghana [17]. In contrast, ERP breast cancer incidence remains low in Ghana compared to US NHB or NHWs.…”