HOME > Doctor’s Health Advice > Strategies for Breast Cancer Prevention

  • Doctor’s Health Advice
  • Yuzo Endo, M.D., Ph.D.
  • Masahito Hitosugi, M.D., Ph.D.
  • John E. Lewis, Ph.D.

Doctor’s Health Advice

Doctor’s Health Advice

Pathologist’s advice on how to combat cancer


Strategies for Breast Cancer Prevention

The breast is one of the key organs of reproduction. After a woman conceives and delivers a baby, the breast provides nourishment for the child’s growth. Hormones control the production and excretion of breast milk, as well as other functions such as breast development and cell proliferation . Estrogen is one of the key hormones in breast activity, in other word growth and maturation, but it can also be responsible for the development of breast cancer and serve as an obstacle for breast cancer treatment. Progesterone is another key hormone for lactation, but it is also implicated in breast cancer development. The irony is that these hormones, when in balance, are indispensible for healthy breasts, yet can also be the key factor in triggering cancer.

Ovaries, because of their role in production of estrogen and progesterone, are also implicated in breast cancer development right up until menopause, because then production of both hormones declines coincidentally under the upper control of hypothalamus and pituitary gland. Yet even after menopause, especially the more adipose cells of the breast, the more they store and release estrogen. For this reason, maintaining a healthy weight with reasonably low fat stores (including in the breast) will lower the risk of developing breast cancer. A low-fat and moderate-calorie diet is recommended as part of a breast cancer prevention lifestyle.

A diet high in pork, beef and dairy, rather than a vegetarian diet, will increase breast cancer risk. Recent research has revealed that the burnt portion of meats and smoked foods contain chemicals that are implicated in breast cancer development. If a person does frequently consume these high risk foods, it would be wise to start breast cancer screenings at age 40.

Additionally, women who start menarche at younger age, who had a greater number of years than average from the menarche to menopause, or who were never pregnant or delivered a child, are at higher risk of breast cancer. Women who are predisposed to weight gain are also at higher risk. Body Mass Index (BMI) is a good measurement for healthy weight. A BMI of 20-24 is considered healthy, and if a woman is more than 120% of their ideal weight, as according to the BMI, breast cancer screening should be more frequent.

(*BMI is calculated by dividing body weight(kg) by square value of body height(m). 20-24 is regarded as a medium build. Ex. weight 70kg, height 1.6m; 70/1.6×1.6=27.3 = obesity)

A woman who consumes a diet high in vegetables, fruit and soy, with low consumption of beef, pork and dairy, and an ideal BMI, is generally going to have a lower risk of breast cancer. Even under ideal circumstances, a woman should start breast cancer screenings by age 50.

In North America, breast cancer rates continue to increase with no signs of slowing. Breast cancer has been labeled as so-to-speak an epidemic, and national campaigns have been enacted to reverse the trend. Even in Japan, there is concern about increased breast cancer rates, which has been attributed to the growing popularity of Western diets laden with fat. Only certain types of fats, such as animal fats like butter and lard, are implicated as increasing cancer risk, and traditionally vegetable based fat was recommended as a healthy substitution. It was thought that vegetable fats would also help prevent heart attacks and cerebral vascular accidents, however it has now been recognized that vegetable fats can also cause problems. Vegetable fats found in salad dressing, cooking oil, margarine, and vegetable shortening were once thought to be low in saturated fats and cholesterol. However, research reveals that consumption of small amounts of artificial trans-fats, as can be found in some processed vegetable oils, also correlates with increased mortality from heart disease and breast cancer.

In response to these health concerns, the FDA requires food labels to state the levels of trans fat in a single serving. In North America, some margarines are available without trans fats. Another reflection of fat awareness is the popularity of olive oil, due to its squalene and “good” fat content.

In fact, fatty acids can be divided into beneficial fat and bad fat, similar to cholesterol. We need to pay attention to how fats are processed. When we look at the quality of fats found in prepared salad dressing, margarine, white bread, cake, biscuits, snacks, and ice cream, we should consider eating less of them, just as with beef and pork.

The popularity of soybean consumption is considered one of the primary reasons why the morbidity of breast cancer is still lower in Japan than in North America. Soy beans contain various chemicals that are effective in preventing cancer. Among them, the most significant are isoflavones, specifically genistein. Genestein is a very strong phytoestrogen that counteracts estrogens cell proliferation activity and helps maintain healthy breast tissue.

Traditional Japanese soy products, including tofu (soy bean cake), natto (fermented soy bean), miso soup (soup seasoned with fermented soy bean paste), atsuage (fried soy bean cake), and kinako (soy bean powder), contain phytoestrogens and other various chemicals which are effective in controlling cancer. Hopefully those foods are fully utilized in a diet focused on cancer prevention.

One of the most important factors in fatty food with regards to cancer formation is bile secreted from the liver. Bile is composed of cholic acids and cholesterol made from cell membranes of our reformed cells, especially from red blood cells destructed daily in the spleen. In the body, bile is so-called detergent or soap. Bile might be changed in the gut by bacterial flora to be carcinogenic, for instance, methylcholanthrane and others. Therefore, the more food may be oily, the more bile may be secreted and the more gut juice may be changed to be carcinogenic.

Breast cancer examination

Breast cancer examination in the physician’s office may include palpation of the mammary glands, imaging, such as mammogram and the more sensitive digital mammography, ultrasound and MRI, which does not use radiation. Each of these methods has pros and cons. Self-examination can be done monthly by lying down and palpating the breasts gently not with the fingers, but with palm of the hand, by massaging the breasts in a circular motion. If a lump is palpated, even if it is small, it should be examined by a physician.

The National Cancer Institute (NCI) in the US recently released a report about research that was conducted on Chinese women in Shanghai, which concluded that palpation did not aid in early detection of breast cancer. However, it should be noted that the difference in breast size between Asian women and Caucasian women in North America is quite significant, and tumors in smaller breasts can be detected more easily with palpation. So despite the report’s conclusion that palpation is not effective for early detection, women should not be discouraged from regular self-examination. This research also appropriately emphasizes the importance of routine breast examination with mammography or ultrasonography. MRI is strongly recommended because mammography can be painful.

When a woman feels a lump in her breast, or discovers secretion in her bra, she should visit a gynecologist/oncologist, or a surgeon. Fortunately for women, the number of clinics with female gynecologists is increasing. If a lump is discovered, a biopsy may be taken from the mammary gland. Stereotactic biopsy enables more exact localization of tumor. Then histopathological examination on the tumor sample can be done after a fine needle biopsy or resection. There may also be cytodiagnosis on mammary gland secretions. Most breast cancers are hormone-dependent, specifically estrogen- or progesterone-dependent. Breast cancer has receptors for female hormones, and may be hormone-dependent , although some breast cancers are not dependent on any kind of hormones. In pathological analysis, those hormone receptor can be detected, which helps doctors decide what specific medicine should be administrated.

Genetic testing has become more commonly utilized in clinical medicine to help predict prognosis. The test results are reflective of health status and copies of the results should be maintained by the patient.

Breast cancer and hormone receptor

As stated previously, breast cancer can be estrogen and/or progesterone dependant. In the case of breast cancer surgery, it is essential to determine whether or not cancer cells have receptors to these hormones. This can be diagnosed through pathology tests as part of the immunohistochemical examination. The lab evaluation should be kept at the hospital where the surgical procedure occurred, as the results help determine the course of treatment. Cell growth receptor, Her-2, is also one of the most important item to evaluate the outcome of the patients.

There is a study that compared the effects of the combination of an anticancer drug and tamoxifen versus tamoxifen alone. The purpose of tamoxifen is to reduce estrogen levels. This study was conducted on patients with breast cancer without lymph node metastasis, who had surgical intervention and determination of estrogen receptor status. In cases of estrogen receptor-positive breast cancer, chemotherapy showed no effects, and no difference in outcome was seen between patients receiving the drug combination versus patients receiving tamoxifen alone. As for both groups, the seven-year survival rate was slightly less than 90%, and 80 of the group overall maintained good health. On the other hand, in the cases of estrogen receptor-negative breast cancer in patients without lymph node metastasis, the combination of anti-cancer drugs and tamoxifen was more effective. The seven year survival rates of this group were 85-90%, and those patients maintained good health. But with tamoxifen alone, 70% of patients had a seven year survival rate and maintained good health.

The interpretation of the results of this study and the different treatments should be explained to breast cancer patients to help them make truly informed choices. Doctors need to explain these results because the effect of chemotherapy on cancer is not nearly as straightforward as the effects of antibiotics on a bacterial infection. In order to cure a bacterial infection, there are no choices other than antibiotics, but with cancer, chemotherapy is not the only option and patients need to understand the alternatives and the expected outcome of each. It is important for physicians to take adequate time to consult with their patients.
Another method to attack breast cancer cells involves blocking estrogen receptors. This acts to starve cancer cells by blocking the supply of estrogen, and this method can be used with postmenopausal women who naturally have lower estrogen production from the ovaries. One should take into consideration that subcutaneous fat throughout the body continuously supplies estrogen, therefore, reducing fat through exercise will help prevent breast cancer.

Aromatase, an enzyme found in subcutaneous fat, can elevate estrogen levels by converting androgens to estrogen. An aromatase inhibitor cuts off the supply of estrogen by inhibiting this enzyme, and suppresses the growth of estrogen receptor-positive breast cancer cells. One aromatase inhibitor is called Letrozole, and results from a Phase Ⅲ clinical trial examined the effects of this medicine. The report found that letrozole showed better results than tamoxifen regarding the five year survival rates after breast cancer resections.

Choices for cancer treatment methods

It is important to educate a patient on their cancer treatment options. In the initial consultation when a person is told they have cancer, they may experience shock and have difficulty processing and absorbing the information they are given. In the long run, a cancer patient has many issues to deal with, such as scheduling appointments, choosing doctors, learning about their illness and simply dealing with their own personal affairs.

Most cancer patients do not have a background in medicine or oncology, so it is very important that the they take the necessary time to learn about the variety of options for their type of cancer, evaluate the possible outcomes, such as success rates and risks, and work with their doctor to come up with a plan that makes them comfortable. Too often a patient feels they have no choice other than to blindly follow their doctor’s instructions. However in most cases, it is not necessary to rush into treatment or make rash decisions. Instead it is much more important to go through the process of learning about their illness in order to make an educated decision.

There are many choices regarding cancer treatments, and unfortunately there is not on clearly reliable choice. Surgery is more than 80% effective as treatment for solid tumor, but other possible treatments do not necessarily have significantly different rates of success.

Be sure to have a good support system during the process of developing a treatment plan; this includes not only a trustworthy doctor, but also a nurse, a person who specializes in the medical system, and a good technical resource. This is a process that focuses on information gathering and analyzing statistics. From the perspective of the patient, analyzing medical data such as survival rates is the equivalent of gambling on his life. For example, if a patient was told there was a five year survival rate of 50%, they may be shocked at the concept that only half of the patients survive five years. What this doesn’t take into consideration is that survival rates only determine whether a person will live or die over a period of time, and do not reflect other important pieces of information such as the possible adverse effects of a treatment such as chemotherapy. Chemotherapy may be effective by preventing the spread of solid tumors, but in many cases, it does not effectively extend the person’s lifespan. Sometimes it only adds a few months or a year.

The average two year survival rate for rapidly progressing breast cancer has not improved in the past 50 years, despite advances in chemotherapeutic drugs. But still, it is important to use the statistics that are available to choose an appropriate chemotherapy drug for this disease. The progression of the cancer can be tracked with pathology tests to determine whether it is spreading rapidly, moderately, slowly, or if it is dormant. The long term effects of the drug on the body cannot be predicted however.

Survival rates tend to be general statistics, but more precise predictions can be made by eliminating specific characteristics of patients. An important question to ask is “what if a patient doesn’t do any treatment?”. Modern medicine doesn’t conduct research which compares a treatment versus no treatment (or placebo), therefore survival rates for absence of treatment have not been developed. The lack of scientific research on absence of treatment is one of the significant limitations of modern medicine.

When given the diagnosis of cancer, it is important to take into consideration the survival rate statistics and adverse effects of chemotherapy drugs, and use that information to make a decision. It is appropriate to have concerns about side effects of chemotherapy, but to not decline those drugs based solely on that concern. New treatments continue to be developed, so be sure to be open to the new information offered by the support team.

After leaving the hospital, many patients require support not only from their medical team, but also people involved in medical services and their family. Immediate support is essential for a patient who needs long term cancer treatment. The current medical system is lacking in these peripheral services and the current health insurance system cannot afford to establish new programs for assistance.

The concept of “informed consent” has been promoted in order to preserve the dignity and rights of the patients. This philosophy has progressed into patients demand for medical information disclosure and establishing patient’s rights for them to be actively involved in their treatment. Informed consent does not adequately protect the patient, as contemporary medicine is complex and the patient must go far beyond simply having faith in their doctor. Patients need to thoroughly evaluate all the treatments options that are offered and make their decision based on impartial information.




Yuzo Endo, M.D., Ph.D.

Yuzo Endo, M.D., Ph.D.
Hamamatsu University School of Medicine

1969.9: Graduated from Medical School, University of Tokyo Consultant pathologist in Hamamatsu University, Medical School, and Fujimoto General Hospital. Medical Consultant in conventional and integrative medicine.

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