Stage at diagnosis and tumor characteristics among young women and men with breast cancer, in Ethiopia and Sweden, a descriptive cross-sectional study.

Abstract

Background: Breast cancer patients diagnosed in sub-Saharan Africa (SSA) are generally younger, and present with more advanced stage of disease, than those in high-income countries. In addition, male breast cancer appears to be more prevalent in SSA. Young women and men are typically not included in national mammography screening programs. Therefore, the aim of the present study was to compare clinical and pathological data from a breast-cancer-patient cohort not covered by mammography screening, in a low-income country in SSA (Ethiopia), to a similar patient cohort from a high-income country in Europe (Sweden).

Methods: Women (< 40 years) and men (all ages) with breast cancer were recruited in Ethiopia and Sweden. Patient- and tumor data was collected. In Ethiopia, 100 study participants were recruited prospectively from the Departments of Surgery and Oncology at Tikur Anbessa Specialized Hospital. In Sweden, 100 study participants were enrolled retrospectively from the Department of Oncology at Södersjukhuset, Stockholm.

Results: Ethiopian and Swedish study participants were diagnosed in tumor stage I (3.3% vs 27.0%), stage II (33.7% vs 45.0%), stage III (44.6% vs 23%), and stage IV (18.5% vs 5.0%). This represents a significant difference in stage distribution between groups (p < 0.001). A majority of the cases were ER-positive (79.5% in Ethiopia and 69.0% in Sweden, p = 0.08). The ER- and/or PgR-positive/HER2-negative subtype was the most common in both groups: (68.0% in Ethiopian patients and 47.5% in Swedish patients). The HER2-positive (any ER) subtype accounted for 20.5% in Ethiopia and 26.7% in Sweden, while triple-negative breast cancer accounted for 11.5% (Ethiopia) and 25.7% (Sweden).

Conclusions: There were large disparities in stage at diagnosis between Ethiopian and Swedish young women and men with breast cancer, with a higher proportion of late-stage disease seen in Ethiopians although, due to young age/male sex, none of the Swedish cases were diagnosed in the national mammography screening program. There was a high rate of ER-positive breast cancer at both sites, and the triple-negative subtype was more than twice as common in Swedish patients.