Mode of detection matters: Differences in screen-detected versus symptomatic breast cancers.

OBJECTIVE: Although extensive analyses evaluating screening mammography for breast cancer have been published, some utilized databases do not distinguish between modes of detection, which confounds the conclusions made about the impact of screening mammography. METHODS: A retrospective cohort study of women at our institution with pathologically-proven breast cancer from January 2015 to April 2018 was conducted. Subjects were categorized by their mode of diagnosis: screening or non-screening. Patient demographics, tumor characteristics, and treatments were compared between detection methods using Wilcoxon rank-sum test for continuous variables and chi-squared or Fisher's exact test. RESULTS: 1026 breast cancers were analyzed. 80.8% of screen-detected breast cancers were invasive. Compared to symptomatically detected cancers, screen-detected were smaller (median size 8 mm vs. 15 mm, p < 0.001), less invasive (80.8% vs. 94.3), had a lower pathologic grade (29% grade 3 vs. 45.7%, p < 0.001), a lower clinical stage, and less aggressive histology (51.9% low Ki67 vs. 30.5%, and 88.2% HER2 negative vs. 76.6%, p < 0.001). Screen-detected cancers were less likely to have extramammary disease (13.2% positive lymph nodes vs. 34.0% and 0.4% distant metastases vs. 6.9%, p < 0.001). Women with screen-detected cancers were more likely to undergo conservative treatment (74.8% underwent lumpectomy vs. 59.9%, and 80.0% received no chemotherapy vs. 51.3%, p < 0.001). CONCLUSION: In this study, while the vast majority of screen-detected cancers were invasive, they were more likely to be smaller, less aggressive, and a lower pathologic grade and clinical stage. Furthermore, women with screen-detected cancers were less likely to have extramammary disease and more likely to undergo conservative treatment.

Breast cancer in women under age 40: A decade of trend analysis at a single institution.

BACKGROUND: Women should be evaluated for breast cancer risk by age 30 to assess for screening need. Recent trends in breast cancer in this population may further inform recommendations. OBJECTIVE: The aim of this study was to analyze trends over time in the rate of breast cancer, tumor characteristics and treatment in women under age 40. METHODS: Retrospective cohort study of women under age 40 at our institution diagnosed with breast cancer from January 2007 to April 2018 was conducted. Patient demographics, tumor characteristics and treatment outcomes were collected. Descriptive statistics and the Mann-Kendell Trend test were calculated. Two-proportion z-tests were used to compare proportions of stage, pathology and treatment between 2007-2013 and 2014-2018. RESULTS: 197 women under age 40 were treated for a new diagnosis of breast cancer at our institution. A higher proportion of women were diagnosed with invasive carcinoma in 2013-2018 (91%) compared to 2007-2012 (78%), p = 0.008. A higher proportion of women were diagnosed with advanced stage disease (stage III-IV) in 2013-2018 (24%) compared to 2007-2012 (2%), p = 0.001. No statistically significant evidence for an increasing trend of overall rate of breast cancer over the last 11 years (p = 0.419) was observed. CONCLUSIONS: While no statistically significant increase in overall rate of breast cancer was noted, an increase in invasive and later staged breast cancers was observed. CLINICAL IMPACT: Rise in more aggressive cancers in a population that is largely not screened may have implications both on the individual young woman's morbidity as well as on a public health level.