Is Step Down Assessment of screen‐detected lesions as safe as workup at a Metropolitan Assessment Centre?

Abstract

Objective: BreastScreen WA offers population mammographic screening via fixed clinics in the metropolitan area and mobile clinics that visit country areas every two years. If an abnormality is suspected following mobile clinic screening, women undergo Step Down Assessment; diagnostic further views are performed at the mobile clinic and if a possibly significant abnormality persists, country women are referred to a Perth Metropolitan Breast Assessment Centre. The purpose of this retrospective cohort study was to determine if Step Down Assessment in country Western Australia offered the same diagnostic effectiveness as screening and assessment in the metropolitan area. Methods:The study included all screening episodes at BreastScreen WA between 1999 and 2008. Screening episodes from metropolitan and mobile clinics were compared according to the primary outcomes of cancer detection rates, recall and further investigations, cancer size, return to screen rates and interval cancers.Results: Cancer detection rate per 1,000 screening episodes was lower for the country program than the metropolitan program (3.07 (2.84-3.31) versus 7.04 (6.82-7.27)). The false negative (interval cancer) rate was lower for Step Down Assessment than for the metropolitan program. The size of cancers detected was similar for both screening services. Return to screen rates were comparable between both groups. Conclusion:The results indicate that the current service model is providing appropriate diagnostic effectiveness, as well as comparable client satisfaction, for country and metropolitan women.

Mobile Screening Units for the Early Detection of Cancer: A Systematic Review

“…Regrettably, risks of screening may be worsened in settings where follow-up is limited, because individuals with abnormal tests may not return and the period between screening rounds may extend beyond the recommended intervals, thus permitting development of interval cancers. Few studies reported the potential for false negative test results which can be measured as the number of interval cancers occurring within 24 months of a negative test result or by reporting test specificity (13,21,72,76). Using a descriptive single-group study design measuring rates of cancer detection at baseline (cross-sectional), and without follow-up data, it is not possible to assess the rates of false-negative results.…”

“…The quantitative descriptive studies (n ¼ 22) measured various implementation, clinical and service-related outcomes, and generally explicitly or implicitly stated the objective of evaluating the performance of the MSU program. The nonrandomized observational studies (n ¼ 7) sought to answer more specific questions, often with respect to comparisons in screening modalities such as the effectiveness of MSU as compared with fixed clinic screening (13)(14)(15)(16); breast cancer studies comparing digital to film-screen mammography (17,18); cervical cancer studies comparing conventional Pap cytology with liquid-based Pap cytology (Pap-LBC) tests (19,20) or human papillomavirus (HPV) testing with Pap-LBC (21). Two RCTs for mammography screening sought to establish evidence of mortality reductions associated with screening (22,23).…”

Variations in outcomes by residential location for women with breast cancer: a systematic review

“…Results were inconsistent across the five included studies, with a dependence on the time period of data collection. One early (moderate quality) study showed that metropolitan women had higher rescreening rates through the national BreastScreen programme than non-metropolitan women, 66 whereas among four other studies from 1995 onwards, one (moderate quality) study showed no difference in rescreening rates 68 and three studies (two moderate and one high quality) showed that non-metropolitan women had higher rescreening rates. 60 69 …”

Mammograms on-the-go—predictors of repeat visits to mobile mammography vans in St Louis, Missouri, USA: a case–control study

“…This suggests that mobile mammography may be detecting many tumours that otherwise could have gone undiscovered. Even further, mobile mammography has been shown to be accurate and accessible, 9 10 thereby increasing participation rates and improving equity of care. 11 Interestingly, in a study conducted by Lee and Yao 12 , 21.3% of the women surveyed preferred mobile mammography for screening while 7.6% favoured a hospital setting.…”