Socioeconomic and Urban–Rural Disparities in Mammographic Tumor Burden at Breast Cancer Diagnosis: A Regional Screening Study from Eastern Romania

Background/Objectives: Breast cancer mortality remains disproportionately high in Eastern Europe, partly due to delayed diagnosis and limited access to organized screening programs. Socioeconomic deprivation and rural residence may contribute to inequalities in breast cancer detection and disease burden at presentation. This study aimed to evaluate the association between sociodemographic disparities and mammographic tumor burden at breast cancer diagnosis within a large regional screening cohort from Eastern Romania. Methods: This retrospective study was conducted within the ONCOFEM regional breast cancer screening initiative between August 2020 and December 2023. A total of 23,886 asymptomatic women aged 50–69 years underwent screening mammography using fixed and mobile digital mammography units. Sociodemographic variables included residential environment (urban/rural) and vulnerability status. Histopathologically confirmed malignant lesions were analyzed regarding maximum mammographic tumor dimension and focality status (unifocal, multifocal, multicentric). Statistical analysis included Mann–Whitney U tests and Chi-square/Fisher exact tests, with p < 0.05 considered statistically significant. Results: The screened population included 12,652 rural women (53.0%) and 11,234 urban women (47.0%). Urban participants demonstrated significantly higher recall rates compared with rural women (7.75% vs. 4.85%, respectively; p < 0.001). Similarly, the Cancer Detection Rate (CDR) was significantly higher in the urban subgroup, reaching 7.21 cancers per 1000 screened women, compared with 4.19 cancers per 1000 screened women in the rural population (p = 0.002). The final analytic cohort included 134 patients with histopathologically confirmed breast cancer, corresponding to 138 malignant lesions. Median tumor size was 25 mm overall. Rural and vulnerable women demonstrated numerically higher proportions of tumors exceeding 20 mm; however, no statistically significant differences were observed regarding maximum tumor dimensions according to residential environment (p = 0.799) or vulnerability (p = 0.934). Multifocal and multicentric disease represented a minority of cases, without significant associations with the sociodemographic subgroup. Conclusions: Although significant urban–rural differences were identified in screening performance metrics, mammographic indicators of tumor burden demonstrated relatively similar distributions across sociodemographic subgroups. The persistently high proportion of tumors exceeding 20 mm across all groups suggests a substantial burden of relatively advanced disease at diagnosis within the Romanian population. No statistically significant disparities in mammographic tumor burden were identified across the analyzed sociodemographic subgroups; however, the present study cannot determine whether the use of mobile mammography units contributed to this observation.