. 2019 Nov 14;6(1):68–74. doi: 10.1001/jamaoncol.2019.3876

Table 2. Difference Between Starting Age of Breast Cancer Screening Recommended by Guidelines and Risk-Adapted Starting Age of Screening.

Family History	Youngest Age at Diagnosis in FDRs, y	Example Age, y^a	Patients, No.	Recommended Starting Age, y
				40			45			50
				ACR^b	Evidence^c	Diff^d	ACS^b	Evidence	Diff^d	USPSTF, IARC^b	Evidence	Diff^d
Whole population	NA	NA	118 953	40	40	0	45	45	0	50	50	0
No family history	NA	NA	102 751	40	41	−1	45	46	−1	50	52	−2
0 FDR + 1 SDR	NA	NA	2512	40	37	3	45	42	3	50	45	5
0 FDR + ≥2 SDRs	NA	NA	276	40	36	4	45	39	6	50	41	9
1 FDR + 0 SDR	All ages	50	12 075	30	35	−5	45	38	7	50	40	10
	<40	35	691	30	30	0	45	34	11	50	36	14
	40-44	43	916	30	32	−2	45	36	9	50	38	12
	45-49	47	1426	30	34	−4	45	37	8	50	39	11
	≥50	55	9042	30	36	−6	45	39	6	50	41	9
1 FDR + ≥1 SDRs	All ages	50	544	30	32	−2	45	36	9	50	38	12
	<40	35	55	25	23	2	45	25	20	50	26	24
	40-49	45	123	30	32	−2	45	35	10	50	37	13
	≥50	55	366	30	34	−4	45	37	8	50	38	12
≥2 FDRs + ≥0 SDRs	All ages	50	795	30	28	2	45	32	13	50	35	15
	<50	45	449	30	23	7	45	26	19	50	27	23
	≥50	55	346	30	33	−3	45	35	10	50	36	14

Abbreviations: ACR, American College of Radiology; ACS, American Cancer Society; Diff, difference; FDR, first-degree relative; IARC, International Agency for Research on Cancer; NA, not applicable; SDR, second-degree relative; USPSTF, US Preventive Services Task Force.

^{^a}

Example of a possible youngest age at diagnosis of affected FDR.

^{^b}

Starting age of screening per screening guideline.

^{^c}

Evidence-based risk-adapted starting age of screening per the present study.

^{^d}

Diff: Age recommended by guidelines minus risk-adapted starting age per the present study. The difference indicates how many years earlier (denoted without minus sign) or later (denoted with minus sign) the screening should be done compared with the general recommended starting age of screening.