Retrospective Cohort Analysis of Outcomes Among Young Onset Breast Cancer Patients in Kijabe, Kenya

Breast cancer remains one of the leading causes of morbidity and mortality worldwide, especially for regions of sub-Saharan Africa where little is known about how age of diagnosis relates to breast cancer outcomes. Our study evaluated differences in characteristics and outcomes between those diagnosed with young onset versus average onset breast cancer at a tertiary referral hospital in rural Kenya. We performed a retrospective study evaluating breast cancer patients at Kijabe Hospital, dividing cohorts into young (</ = 45 y at diagnosis) and average onset (>45 y). We analyzed tumor characteristics and social factors. Univariate analysis was performed and Cox regression models were fit to analyze the primary outcome of overall survival and secondary outcome of disease-free survival. There was no difference when evaluating tumor type (P = 0.06), grade (P = 0.06), hormone receptor positivity (P = 0.29), or metastatic presence (P = 0.27). Patients with early-onset disease were more likely to present with larger tumor size (P < 0.01) and more likely to present with larger nodal burden (P < 0.01). There was no significant difference in overall or disease-free survival between the two groups (P = 0.35 and P = 0.5, respectively). Patients with young onset breast cancer presented with larger tumors and more nodal disease. This suggests delays in presentation, which may be due to gaps in screening, poor education about breast cancer signs, or familial and cultural barriers. Despite this, overall and disease-free survival were not different, suggesting that once diagnosed, younger patients may be treated more aggressively or respond better to treatment. Additional studies are needed to explore these intricacies.