Table 4. The recommend age to start screening and inter-screening interval for two types of screening at different percentiles of risk score 1.

Percentile	Start screening agea	Inter-screening interval (year)b	Alternative imaging technique (threshold/study)c
90–100	29	0.4 (4.8 months)	Mammography+MRI (94th/Kuhl et al (2010))
80–90	34	1	Mammography+Ultrasound (85th/Berg et al, 2008)
70–80	39	1.5	Mammography+Ultrasound (76th/Kuhl et al (2010))
60–70	44	2
50–60	50d	3d
40–50	57	4
30–40	69	8
20–30	NA	NA
10–20	NA	NA
0–10	NA	NA

Abbreviations: NA=not applicable; MRI=magnetic resonance imaging.

^aThe optimal age was determined by the age at which the 10-year risk equivalent to 1% of the 10-year risk for the 50th percentile group at age 50 years.

^bThe optimal inter-screening interval for each percentile was determined by the rate of interval cases equal to the threshold at the 3-year inter-screening interval for the 50th percentile group.

^cThe optimal percentile cutoff using the combined alternative imaging technique was determined by the improvement of sensitivity derived by reducing the incidence rate of interval cases until the percentile was equal to the threshold of that at the median value of population with triennial mammography only.

^dRepresenting average-risk group.