Linked Life Data

9768859

Source:http://linkedlifedata.com/resource/pubmed/id/9768859

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-10-20
pubmed:abstractText
The effect of age at exposure on induction of mammary tumors was studied in female rats of the inbred WAG/Rij strain. Groups of 40 animals were exposed to a single total-body dose of 1 or 2 Gy of 137Cs gamma radiation at ages of 8, 12, 16, 22, 36 or 64 weeks and were observed for life. Mammary tumors, identified as nodules persisting and growing for 6 weeks, were resected and classified histologically as carcinoma or fibroadenoma. The age-specific incidence of mammary carcinoma was compared with that in a group of 120 unirradiated control rats, using lifetime statistical analysis with both parametric and nonparametric methods. The excess normalized risk of carcinoma was 0.9 for 1 Gy and 2.2 for 2 Gy in age groups 8-36 weeks, with no significant differences between the age groups. However, irradiation at 64 weeks yielded fewer carcinomas than in the controls, the excess normalized risk being -0.7 and -0.3 for 1 and 2 Gy, respectively. The occurrence of one or more fibroadenomas did not influence the incidence of carcinoma. The present data agree closely with the results reported previously for rats irradiated at age 8 or 17 weeks with a dose of 1.2 Gy. The reduced risk of radiation exposure at midlife is consistent with the available epidemiological data for exposed women. Although our findings have been obtained with a single total-body dose that is several orders of magnitude higher than the multiple doses delivered to the mammary gland during mammography, it is suggested that radiological screening for mammary cancer after the age of menopause will not increase the normal incidence of breast cancer.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0033-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
150
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
442-50
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Induction of mammary tumors in rats by single-dose gamma irradiation at different ages.
pubmed:affiliation
TNO Centre for Radiological Protection and Dosimetry, Rijswijk, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't