Influence of breast compression pressure on the performance of population-based mammography screening

Breast Cancer Research

Table 1 Number of screening examinations and mean measures

	Total	Group 1 ≤ 7.7 kPa	Group 2 7.7–9.3 kPa	Group 3 9.3–10.8 kPa	Group 4 10.8–13.0 kPa	Group 5 > 13.0 kPa
Number of examinations	132,776	26,490	26,617	26,539	26,549	26,581
Mean breast volume (cm³)	974	1511	1135	928	755	540
Mean percent dense volume (%)	7.8	5.7	6.6	7.5	8.4	10.7
Mean force (N)	125.9	112.6	121.5	125.9	130.7	138.9
Mean pressure (kPa)	10.5	6.6	8.5	10.0	11.8	15.6

Thresholds to form the groups were applied at 7.7 kPa, 9.3 kPa, 10.8 kPa, and 13 kPa
An examination with a pressure measurement equal to the threshold was assigned to the lower group

ISSN: 1465-542X