Radiological review of prior screening mammograms of screen-detected breast cancer

Abstract

Objective To perform a radiological review of mammograms from prior screening and diagnosis of screen-detected breast cancer in BreastScreen Norway, a population-based screening program. Methods We performed a consensus-based informed review of mammograms from prior screening and diagnosis for screen-detected breast cancers. Mammographic density and findings on screening and diagnostic mammograms were classified according to the Breast Imaging-Reporting and Data System®. Cases were classified based on visible findings on prior screening mammograms as true (no findings), missed (obvious findings), minimal signs (minor/non-specific findings), or occult (no findings at diagnosis). Histopathologic tumor characteristics were extracted from the Cancer Registry of Norway. The Bonferroni correction was used to adjust for multiple testing; p < 0.001 was considered statistically significant. Results The study included mammograms for 1225 women with screen-detected breast cancer. Mean age was 62 years ± 5 (SD); 46% (567/1225) were classified as true, 22% (266/1225) as missed, and 32% (392/1225) as minimal signs. No difference in mammographic density was observed between the classification categories. At diagnosis, 59% (336/567) of true and 70% (185/266) of missed cancers were classified as masses (p = 0.004). The percentage of histological grade 3 cancers was higher for true (30% (138/469)) than for missed (14% (33/234)) cancers (p < 0.001). Estrogen receptor positivity was observed in 86% (387/469) of true and 95% (215/234) of missed (p < 0.001) cancers. Conclusions We classified 22% of the screen-detected cancers as missed based on a review of prior screening mammograms with diagnostic images available. One main goal of the study was quality improvement of radiologists’ performance and the program. Visible findings on prior screening mammograms were not necessarily indicative of screening failure. Key Points • After a consensus-based informed review, 46% of screen-detected breast cancers were classified as true, 22% as missed, and 32% as minimal signs. • Less favorable prognostic and predictive tumor characteristics were observed in true screen-detected breast cancer compared with missed. • The most frequent mammographic finding for all classification categories at the time of diagnosis was mass, while the most frequent mammographic finding on prior screening mammograms was a mass for missed cancers and asymmetry for minimal signs.

True and Missed Interval Cancer in Organized Mammographic Screening: A Retrospective Review Study of Diagnostic and Prior Screening Mammograms

“…The results from the review study are presented in two separate papers; paper 3 is presenting results from the review of the screen-detected cancers (204) and paper 4 results from the review of interval cancers (205). In this section, results from the review are discussed as a whole, independently from the papers, to visualize a broader perspective.…”

“…No statistically significant differences were observed regarding the classification into the main categories mass, calcification, asymmetry or distortion between missed and minimal signs cancers at prior screening. With regard to further subclassification of the findings (Figure 1.11), differences applied between missed and minimal signs (204). However, this was an obvious consequence of the design, as allocation into the categories missed or minimal signs was merely based on the suspiciousness of the findings, and the different subclasses mammographic findings have different levels of suspiciousness (86).…”

Survival among women diagnosed with screen-detected or interval breast cancer classified as true, minimal signs, or missed through an informed radiological review

“…Recently diagnosed cancer cases were preferred over older cases to facilitate retrieval from the picture archiving and communication systems (PACS). The review is described elsewhere [26].…”

Retrospective Review of Missed Cancer Detection and Its Mammography Findings with Artificial-Intelligence-Based, Computer-Aided Diagnosis

“…The common mammography findings in missed cancer included calcification, asymmetry, and focal asymmetry. However, mass was the most common finding in previous studies [ 18 , 19 ]. Of the included patients, 83.2% of true negative, 78.8% of minimal signs and 61.8% of missed cancer had dense breast.…”

“…Among the IHC types, luminal A was the most common in 16 patients (59.3%). Hovda et al reported that the estrogen receptor positivity was 95% (215/234) in missed cases [ 19 ]. Kim et al reported that the most common presentation in both screening and symptomatic groups was luminal A (63.6% and 54.3%, respectively) [ 22 ].…”