Clinical Differences between Invasive Lobular Breast Cancer and Invasive Carcinoma of No Special Type in the German Mammography-Screening-Program.

Invasive lobular carcinoma (ILC) of the breast is known to have typical molecular, clinical, and pathological characteristics that differ from invasive cancer of no special type (NST). In the German mammography screening program (MSP), we evaluated clinical differences between these tumor types at the time of their detection. Clinical features of NSTs (n = 785) and ILCs (n = 141) diagnosed in the MSP between 2009 and 2016 were compared. Compared to NST, ILC was significantly correlated with advanced age (59.1 years versus 60.6 years) and larger tumor size (1.5 cm versus 2.3 cm). ILC was significantly more frequently associated with moderate tumor differentiation (G2), whereas NST was associated with a higher rate of poorly differentiated tumors (p < .001). Furthermore, ILC presented more often as multifocal tumors (36% versus 11%, p < .001), and mastectomies were performed more often in the ILC group (27% versus 12%, p < .001). ILCs and NSTs had different clinical features at the time of detection. The pathological profile of ILC may explain some of these features. Specialists should be aware of the fact that ILC may escape detection by conventional imaging modalities for a long time, and may present later in life as more advanced multifocal disease.

Stratification of Breast Cancer Risk in Terms of the Influence of Age and Mammographic density. / Stratifizierung des Brustkrebsrisikos hinsichtlich der Einflüsse von Alter und mammografischer Dichte.

PURPOSE: Analysis of the influence of the singular risk factors age and breast density on the 2-year incidence of breast cancer among participants in the German mammography screening program. MATERIALS AND METHODS: The multicenter study includes 111 456 subsequent round digital mammographic screening examinations from four screening units with prospective visual categorization of breast density. Based on detection in screening and during the 2-year interval after negative screening participation (interval cancers), 2-year breast cancer incidences (2 YBCI) (‰) were calculated in the 5-year age groups (5 YAG) of the target group 50-69 years and in the BI-RADS density categories ACR 1-4. Multivariate statistical evaluations were carried out using logistic regression models. RESULTS: With an increase in the 5 YAG, the 2 YBCI increased by 5.0 ‰, 6.7 ‰, 8.5 ‰ to 9.7 ‰, and was significantly different among 55-59, 60-64 and 65-69-year-old women compared to the youngest reference group 50-54 years (odds ratio (OR): 1.34; 1.68; and 1.93; p-value < 0.0001). With an increase in density categories 1-4, the 2 YBCI increased from 2.6 ‰, to 5.8 ‰, 9.6 ‰, and 9.7 ‰. The 2 YBCI differed significantly in breast density categories 2, 3, 4 from reference group 1 (OR: 2.17; 3.65; and 3.76; p-value < 0.0001). Only within the two main breast density groups 2 (frequency 44.3 %) and 3 (44.7 %), a significant increase in the 2 YBCI was observed across the 5 YAG (category 2: 3.7-8.9 ‰; category 3: 5.8-11.7 ‰; p-value < 0.001 each). The 2 YBCI was above the median of 7.5 ‰ in women with breast density category 2 and aged 65-69 years, as well as in women with breast density categories 3 and 4 aged 55-69 years. A 2 YBCI below the median was seen in women between 50-54 years regardless of breast density, as well as women in category 1 in all age groups. CONCLUSION: Within the main breast density categories 2 and 3 (almost 90 % of participants), incidences increase with age to double. A consistently low incidence is found regardless of breast density at a young screening age and in women with the lowest breast density. KEY POINTS: · The risk of breast cancer is modified by age in density categories.. · Women aged 50-54 years have a low risk in all density categories.. · Women in category ACR 1 of any age group have a low risk.. CITATION FORMAT: · Weigel S, Heindel W, Dietz C et al. Stratifizierung des Brustkrebsrisikos hinsichtlich der Einflüsse von Alter und mammografischer Dichte. Fortschr Röntgenstr 2020; 192: 678 - 685.