Radiation and breast cancer: a review of current evidence

Breast Cancer Research

Table 1 A selection of epidemiological studies on populations of women exposed to radiation from the atomic bombings or for medical purposes

	No. of women		No. of breast cancers
Cohort	Exposed	Non-exposed	Exposed	Non- exposed	Breast dose (Sv)^b	Exposure age (years)^b	ERR at 1 Sv^g
Atomic bombings
Life Span Study, Japan [43]	70,165	c	1059	-	0.28	27	1.74
Diagnostic radiation
Tuberculosis fluoroscopy, Canada [27]^a	31,917	c	319	332	0.89	26	0.90
Tuberculosis fluoroscopy, USA [28]	2573	2367	147	87	0.79	26	0.40
Scoliosis, USA [29]^a	4929	644	70	7	0.11	10	5.4
Radiotherapy for benign disorders
Enlarged thymus, USA [30]	1201	2469	22	12	0.69	<1	2.39
Skin hemangioma, Sweden [31]	17,202	c	245	-	0.29	0.5	0.35
Tinea Capitis, Israel [32]	5400	8100	25	27	0.02	7	-
Benign breast disease, Sweden [33]	1216	1874	198	101	5.8	40	0.35
Post-partum mastitis, USA [34]	601	1239	56	59	3.8	28	0.43
	No. of cancer survivors		Observed	Expected			RR/OE
Cancer survivors
Pediatric HL (age < 16) LESG, USA [35]^d	480		29	0.7	f	11.7	55.5
Childhood cancer, CCSS, USA [36]^d	6304		60	3.7	f	7.8	24.7^h
Pediatric HL international [37]	2737		52	3.7	f	16	14.1
HL, UK [38]^d	2085		19	13.5	f	-	2.5^h
Breast cancer, Denmark [39]^e	56,540		529^e	-	2.5	51	1.04
Breast cancer, USA [40]^e	41,109		655^e	-	2.8	52	1.33

CCSS, Childhood Cancer Survivor Study; ERR, excess relative risk; expected, expected number of cases; HL, Hodgkin lymphoma; LESG, Late Effects Study Group; observed, observed number of cases; OE, observed/expected ratio; RR, relative risk. ^aOutcome breast cancer mortality. ^bAverage. ^cIncluded in the exposed group. ^dIn the total cohorts 70–90% of patients were treated with radiotherapy. ^eNested case-control studies among patients with a first breast cancer and matched controls. ^fSpecific dose estimates were not reported in these studies, but HL patients can be exposed to doses of 40 Gy or more [41]. ^gSource: UNSCEAR 2000 report [26], which also has more detailed descriptions of the individual studies. ^hFor the subgroup of patients treated with chest radiotherapy.

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