Environment and Breast Cancer: Science Review
AboutCancer studies: Experimental details
National Toxicology Program Technical Report 92, 1978
Notes
Increased malignant mammary tumors in female rats. Rat, female: 0, 0.004%, 0.01% of feed for 78 wks. 1/98, 3/50, 6/50 T+ adenocarcinoma
Increased malignant mammary tumors in female rats. Rat, female: 0, 0.004%, 0.01% of feed for 78 wks. 1/98, 3/50, 6/50 T+ adenocarcinoma
Route
Route of chemical administration: dermal, inhalation, gavage (delivery directly into the
stomach), in feed, subcutaneous injection (under the skin), or intraperitoneal injection (into the
cavity that contains the abdominal organs).
in feed
Doses
Dosage, frequency, and duration of treatment; the sizes of the groups of animals
involved and what age the animals were at the beginning of the study.
Rat, female: 0, 0.004%, 0.01% of feed
Rat, male: 0, 0.008%, 0.03%
Mouse, female: 0, 004%, 0.04%
Mouse, male: 0, 0.008%, 0.04%
In daily feed for 78 wks. Animals were 6 wks old at start. High dose was begun 41 wks after low dose with its own control.
50 males and 47-50 females of each species were in each dose and control group.
Time after cessation of dosing
How long the animals were observed after the chemical was no
longer being administered and before death of the animals.
Rats: 28-30 wks , mice 17 wks
Mammary tumors, malignant
Development of malignant mammary gland tumors follows the
same format as for benign, as described above.
female rats: 1/98, 3/50, 6/50 adenocarcinoma
Comments
This field contains information on the survival rates of the animals and the body
weight trends in order to evaluate whether these factors were likely to have affected the
generation of mammary gland tumors. Mammary gland tumors tend to develop later in an
animal’s life, so studies with lowered survival could mean that animals died before mammary
gland tumors could develop. Decreased weight (perhaps due to toxicity of the chemical) can
decrease the development of tumors. This field may also contain other comments about the
design or outcome of the study.
Survival- 'adequate numbers survived sufficiently long to be at risk for late-appearing tumors'. Mortality was increased for the female high dose rat group and for high dose groups of mice of both sexes. High dose male rats and mice and both doses of female rats had slightly decreased weight.
High rates of testicular tumors in all male animals.
Other tumors
A list of other tumors that developed in the study that were treatment related.
liver, Zymbal's gland, ear, skin, adrenal
CPDB TD50 (mg/kg-d)
Data excerpted from the CPDB database that is defined as the "dose-rate in
mg/kg body wt/day which, if administered chronically for the standard lifespan of the species,
will halve the probability of remaining tumorless throughout that period". The CPDB
calculated values for all tumor endpoints listed as well as for total tumors. The range of
mammary gland tumors TD50s is provided, as well as an overall range.
Mammary: 11.4, overall: 3.55-8760