Detection Rates and Biopsies. Both groups demonstrated comparable breast cancer detection rates: 1.33% for Group A and 1.13% for Group B. Biopsy rates were higher in Group A (25% of recalls) than in Group B (17.9%). Positive predictive values (PPVs) for biopsies were also higher in Group A (87.5%) compared to Group B (60%).

Table 1: Population and results. Group A: women who performed mammography at fixed unit. Group B: women who performed mammography on mobile units (MMUs). † Mean value and standard deviation. DR: detection rate. PPV: positive predictive value: ^PPV of recalls defined as the percentage of screen-detected breast cancer cases detected among recalls; °PPV of needle biopsies defined as the percentage of screen-detected breast cancer detected among needle biopsies performed at recall assessments.

Histopathological Findings. Group A identified 7 cases of breast cancer and 1 case of atypical ductal hyperplasia (ADH), while Group B identified 3 BC and 1 ADH. Tumor characteristics such as histologic grade, receptor status, and lymph node involvement were consistent with the findings reported in similar screening populations.

Table 2: Histopathological findings. Characteristics of findings in both groups after surgery with prognostic factors. ADH: atypical ductal hyperplasia; DCIS: ductal carcinoma in situ; ER: estrogen receptor; HER2: human epidermal growth factor receptor 2; IDC: invasive ductal carcinoma; LCSI: lobular carcinoma in situ; NST: non-special type; PgR: progesterone receptor.

Recall and Refusal Rates. Group A exhibited a lower recall rate of 6.1% compared to 10.6% in Group B. Dense breast tissue was a common factor in recalls for both groups. Refusal rates for follow-up assessments were significantly higher in Group B (42.9%) than in Group A (9%), indicating a potential barrier to effective care in mobile units.

Table 3: Recalls and refusals. Type of recalls and findings. CNB: core-needle biopsy; FNAC: fine-needle aspiration cytology; MRI: magnetic resonance imaging; US: ultrasound; VABB: vacuum-assisted breast biopsy

Breast Density and Demographics. An inverse correlation between age and breast density was observed, with younger women having denser breasts. In both groups, dense breast tissue accounted for a substantial proportion of recalls (68.8% in Group A and 64.3% in Group B).

Fig 2: Boxplot showing the age distribution by density. The fixed unit group is displayed on the left, and the mobile mammography units (MMUs) group on the right. Age is expressed in years and density is categorized according to BIRADS (5th Edition).

Fig 3: KDE (Kernel density estimates): density distribution of ages for each group.