By Jimmy Downs

Sunday Feb 17, 2013 (foodconsumer.org) -- Gul Kitapcioglu from Ege University in Bomova, Turkey recently published a report titled Epidemiology and Etiology of Breast Cancer suggesting that many things women can do or not do to reduce their risk for breast cancer.

According to the report, which is published in the book titled Principles and Practice of Modern Radiotherapy Techniques in Breast Cancer,  breast cancer risk factors include reproductive factors, obesity or body mass index, diet, oral contraceptive use, use of hormone replacement therapy, smoking, alcohol consumption, and heredity. (of course the list is incomplete, editor's note)

The author cites the World Health organization as declaring in an August 2005 report that estrogen is a carcinogen in women and exposure to estrogen increases risk of breast cancer.   Anything that can increase a woman's exposure to estrogen can be a risk factor.  That is why women who produce high concentrations of endogenous estrogen or exposure to exogenous estrogen from oral contraceptives and hormone therapy are at higher risk for breast cancer.  Younger age at menarche, older age at menopause, late age at first full term pregnancy or never giving birth place a woman at higher risk for breast cancer because all these lead to high exposure of the woman to estrogen.

On the other hand, multiple full term pregnancies and early age  of pregnancy, early menopause and late menarche reduce the risk of breast cancer.  Full term pregnancy can mature the breast making the tissue more resistant to carcinogenesis. Additionally, breastfeeding also render some protection against breast cancer.

Obesity - Obesity has been associated with a twofold increased risk for breast cancer in postmenopausal women even though the association has not been observed among premenopausal women.  A study observed that a net gain of 55 pounds of body weight after the age of 18 years was associated with 55 percent increased risk for breast cancer, compared with those who did not gain body weight.  A gain of 22 pounds or more postmenopause was correlated with an 82 percent increased risk.  The increase in the risk of breast cancer induced by obesity has something to do with estrogenic hormones.

Diet - High fat diet has been associated with increased risk for breast cancer probably because dietary fat promotes the production of estrogen.

Oral contraceptive use - Oral contraceptives are  made of estrogen, which is why the birth control method can increase risk of breast cancer.  The author cites a study as finding that using oral contraceptive therapy made of estrogen and progesterone were more riskier than a therapy made of estrogen alone.  Women using the estrogen plus progestin contraceptive for less than 5 years increased the risk of breast cancer by 15 percent and for longer than 5 years, the risk was increased by 53 percent.

Hormone replacement therapy - Hormone replacement therapy is intended to ease menopausal symptoms such as hot flashes.   Because hormone replacement therapy is made of at least estrogen,  it is not surprise that this treatment was found in trials to increase breast cancer risk and heart disease risk.  The increased risk persists even years after the treatment.

Smoking - Tobacco smoke carries a variety of carcinogens and it can increase risk of not only lung cancer, but also breast cancer among other things.   A longer period of smoking and smoking at a younger age are found more harmful.

Alcohol - Many women fail to recognize that alcohol is a potent carcinogen that increases risk of breast cancer among other things.   A study recently found, which is not mentioned in the author's report, that alcohol consumption is responsible for 65% of all deaths from breast cancer, which means that in the United States, each year, more than 20000 American women die from breast cancer because of their drinking alcohol.  Be aware that alcoholic beverages have been recognized officially by the U.S. National Toxicology Program as a human carcinogen, and they are particularly potent for breast cancer carcinogenesis.

Heredity - Faulty genetics can lead to the development of breast cancer.   Luckily that faulty genetic factors such as BRCA1 and BRCA2 is responsible for only 5 to 10 percent of all breast cancers. 

In summary, reproductive factors that affect the risk of breast cancer include older age at menopause, post menopause breast density, increased bone density, older age at first full term pregnancy, younger age at menarche, older age of menopause, not breastfeeding, induced abortion or voluntary termination of pregnancy, oral contraceptive use, hormone replacement therapy use, and obesity. 

Of course, many other important risk factors are not mentioned in the report.  Remember that the report is published in a book on radiotherapy.  So the risk of medical radiation used in diagnostics, cancer screening, and cancer treatment, which can cause breast cancer, is ignored by the author.  According to Dr. John Golman, a late nuclear physician who was an authority in nuclear medicine, 75 percent of all breast cancers are associated with exposure to medical radiation.  Recently, an authoritative organization has recognized two major breast cancer risk factors, one is radiation and the other is hormone replacement therapy. Other risk factors include but not limited to, overnight shift work, physical inactivity and stress.