Outcomes of an Opportunistic Screening Mammography Program Using the Mobile Mammography Unit in Sindh, Pakistan

This study evaluated opportunistic screening mammography outcomes in a mobile mammography unit (MMU), performed for breast cancer detection among populations with limited access to breast imaging in Pakistan.  Methods: This cross-sectional study was conducted among women undergoing screening at the MMU stationed at two secondary hospitals of Aga Khan University Hospital from March 2019 to March 2021. Women aged ≥40 years and those <40 years at high risk for breast cancer were screened. Performance indicators included the cancer detection rate (CDR), BI-RADS assessment, and recall rate.

1042 women were screened at the MMU. The median age was 49 years. 76.6% of women underwent screening for the first time. 64.7% of women had dense or heterogeneously dense breasts; however, heterogeneously dense breasts constituted the largest proportion (57.1%). The overall recall rate was 65.5%, out of which breast ultrasound was advised in 59.8% for dense breasts and additional mammographic views in 10.3% because of suspicious findings. Biopsy was advised for 20 women, of whom 13 (65%) completed the biopsy, yielding 11 cancers (CDR 10.6 per 1,000), Of all the diagnosed malignancies, 8 were invasive, 2 were ductal carcinoma in situ and histology of one cancer was unknown, with 72.7% of invasive cancers being node negative.

This cohort of a largely first-time screened population with dense breasts yielded a high CDR and predominantly early-stage, node-negative cancers. The elevated CDR highlights a substantial reservoir of undiagnosed disease in underserved populations. MMU-based screening is known to be effective at identifying early breast cancers; however, its deficiency in a low-middle-income country (LMIC), such as Pakistan, calls for the immediate establishment of screening programs, preferably in mobile units across the country. Integrating MMUs with targeted outreach, on-site diagnostic tools, and patient navigation may improve follow-up adherence and further enhance early detection efforts.