Mammographic density: a hormonally responsive risk factor for breast cancer.
ABSTRACT Mammographic density refers to radiologically dense breast tissue, and reflects variations in the tissue composition of the breast. It is positively associated with collagen and epithelial and non-epithelial cells, and negatively associated with fat. There is extensive evidence that mammographic density is a risk factor for breast cancer, independent of other risk factors, and is associated with large relative and attributable risks for the disease. The epidemiology of mammographic density, notably the inverse association with age, is consistent with it being a marker of susceptibility to breast cancer. Cumulative exposure to mammographic density may be an important determinant of the age-specific incidence of breast cancer in the population. All risk factors for breast cancer must ultimately exert their influence by an effect on the breast, and these findings suggest that, for at least some risk factors, this influence includes an effect on the number of cells and the quantity of collagen in the breast, which is reflected in differences in mammographic density. Many of the genetic and environmental factors that influence the risk of breast cancer affect the proliferative activity and quantity of stromal and epithelial tissue in the breast, and these effects are reflected in differences in mammographic density among women of the same age. Some of these influences include endogenous and exogenous hormones, and the menopause. A better understanding of the factors that influence the response of breast tissue to these hormonal exposures may lead to an improved understanding of the aetiology of mammographic density and of breast cancer.
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ABSTRACT: Breast cancer risk factors have been studied for the past three decades, and the single most important risk factor is age. Hormonally linked adult reproductive and anthropometric risk factors contribute to the etiology of postmenopausal breast cancer. The risk of breast cancer increases among women older than 50 years of age who have benign breast disease, especially those with atypical ductal or lobular hyperplasia. Lobular carcinoma in situ increases risk significantly, as do a family history of breast cancer in first-degree relatives and the presence of BRCA1 or BRCA2 mutations. Diet, exercise, and environmental factors play a very small role in overall risk. Mammographic breast density increases relative risk fivefold among women with the highest density, and breast cancer risk is two to three times greater in women with elevated serum levels of estradiol or testosterone. Multivariate risk models allow determination of composite relative risks and cumulative lifetime risk, although improved models for African American women are required. For postmenopausal women, newer risk models are being developed and validated that include age, breast density, race, ethnicity, family history of breast cancer, a previous breast biopsy, body mass index, age at onset of natural menopause, hormone therapy, and previous false-positive mammography. A simpler model that includes only age, breast cancer in first-degree relatives, and previous breast biopsy performs well for estrogen receptor-positive breast cancer in postmenopausal women. As many as 10 million women in the United States are at increased risk, and clinicians are obligated to identify these women and manage their risk appropriately.Menopause (New York, N.Y.) 01/2008; 15(4 Suppl):782-9. DOI:10.1097/gme.0b013e3181788d88 · 2.81 Impact Factor
Article: Alcohol and Cancer: Biological Basis[Show abstract] [Hide abstract]
ABSTRACT: 1. For decades, it has been well documented that alcohol intake increases risk for cancers of the upper aerodigestive tract (oral cavity, pharynx, larynx, and esophagus), especially at high levels of intake, as well as for breast, colon, and liver cancers. 2. Many types of cancer associations were observed for all types of alcoholic beverages, suggesting that ethanol is the main carcinogenic constituent of alcohol drinks. 3. Alcohol has multiple actions in modifying carcinogenesis, not only directly, such as disordering cell membranes, but also indirectly, such as a consequence of ethanol oxidation to acetaldehyde and other reactive intermediates. 4. The magnitude, specificity, and variability of ethanol’s actions can depend on the dose and duration of exposure and on specific biochemical and molecular characteristics of the tissues to which ethanol comes in contact. 5. The possible mechanisms underlying alcohol’s carcinogenicity include the causation of DNA damage by alcohol’s metabolic product acetaldehyde, alcohol’s effect in increasing estrogen levels, alcohol being a solvent for carcinogens, alcohol-induced generation of reactive oxygen species, alcohol-associated alterations in nutritional status, and deleterious effects of alcohol on the host immune system.
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ABSTRACT: The degree and pattern of density in a mammogram is a reflection of the amount and distribution of fibroglandular tissues in the breast. Mammographic density has been known to make breast cancer harder to detect but, lately, in addition to that, mammographic density has been found to be a risk factor for breast cancer. The aim of this work was to study this fairly new concept about mammographic density, as a risk factor for breast cancer. This is a retrospective study of 210 mammograms that demonstrated breast cancer. They were classified according to their degree of density following the BI-RADS classification. This study showed that breast cancers were 4.4 times more in dense mammograms than in hypodense ones among women above 40 years of age. This study reached results similar to the world literature that highly dense mammograms are risk factors for breast cancer, and hence women above the age of forty with dense mammograms need to have a regular breast follow up.