Abstract P3-01-02: Trends in positive predictive values following transition from screen film to digital mammography

Abstract

Abstract Purpose Our health region converted from screen-film mammography (SFM) to digital mammography (DM) in 2005. DM has several advantages over SFM, including superior contrast resolution, less noise, and opportunities for image optimization through post-acquisition processing; although, the spatial resolution of DM is inferior to SFM. We sought to determine what effect this transition may have had on positive predictive values (PPVs) for malignant and premalignant lesions. Methods From our institution's breast biopsy database, we retrospectively reviewed core biopsy results for mammographic calcifications performed in the years 2001-2004 (SFM years) and 2009-2012 (DM years). We subsequently determined the PPV3 (detection of malignancy after biopsy) for each group of years (SFM and DM). We then performed subgroup analysis to calculate PPVs for each of ductal carcinoma in-situ (DCIS) without invasion, DCIS with invasion, and premalignant lesions. Premalignant lesions included atypical ductal hyperplasia, atypical lobular hyperplasia, and lobular carcinoma in-situ. Results A total of 4787 biopsies in 4633 patients were reviewed. The comparative detection of cancer after biopsy performed for mammographic calcification between SFM and DM was not statistically significant (PPV3 = 23.5% and 24.0%, respectively; P=.71). Upon further analysis, however, PPV for premalignant lesions increased (SFM=6.6% and DM=8.9%; P<.01) and PPV for DCIS without invasion increased (SFM=15.5% and DM=18.2%; P=.015), while PPV for DCIS with invasion decreased (SFM=8.0% and DM=5.8%; P<.01). Conclusion We observed no significant impact on PPV3 for calcifications following the transition from SFM to DM; however, our subgroup analysis suggests that with digital mammography we are now detecting a statistically significantly lower proportion of DCIS with invasion but greater proportions of DCIS without invasion and premalignant lesions. As the natural history of these lower-grade lesions, particularly in the premalignant category, is still not entirely understood, the significance of potentially detecting more of these earlier cancers/precancers is uncertain. Citation Format: Motiuk DA, Dahl P, Roy E, Docktor B-J, Burrowes P. Trends in positive predictive values following transition from screen film to digital mammography [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-01-02.