Introduction

Breast cancer is influenced by female hormones such as estrogen, and conversely, prostate cancer is influenced by androgenic hormones because of the physiological dependence.

The prostate, about the size of a walnut, is part of the glandular system, like salivary glands or the breast, and secretes fluid which prolongs the lifespan of sperm. The prostate is situated right below the bladder in men and surrounds the urethra. Women also have remnants of a prostate.

Dysuria, which sometimes occurs in older men, is caused by an enlarged prostate and constricted urethra. This is known as prostate hypertrophy which is benign and occurs in many older men. Sometimes it is complicated by cancer, but dysuria that is caused by cancer indicates that the cancer has already progressed considerably. From this perspective it is important to determine whether dysuria is caused by prostate hypertrophy or prostate cancer.

In an examination to rule out prostate cancer, serum PSA and ultrasonography are very important tools. Serum PSA levels may be slightly higher when prostate hypertrophy is accompanied by inflammation. But in the primary stage of prostate cancer, PSA shows a slight abnormality, and it should be emphasized that if the PSA level is constantly higher over normal range, even if very slight, further examination should be done as a precaution.

Diagnosis may be made through prostatatic fine needle biopsy. Under local anesthesia, fine needle biopsy is given through the urethra or rectum. High tech imaging tests including ultrasonography and CT scans have made progress. By utilizing these technologies, it is also possible to partition the prostate into smaller sections, and identify the exact location of cancer in imaging in 3D.

Pathological tissue examination is conducted from core biopsies, and final microscopic diagnosis is made. As stated in the breast cancer article, requesting a copy of the pathological tissue examination report is recommended as the public document.

What is prostate cancer?

The prostate develops, functions, and is maintained under the influence of androgenic hormones. Some cancer cells in the epithelial tissue of the prostate have androgen receptors, but others don’t. Prostate cancer prevention may include antioxidants, similar to other cancer prevention methods, and treatments using anti-hormones like antiandrogens, which are specific to treating prostate cancer. Taking it a step further, the ultimate treatment method for progressive prostate cancer is removing the testes, which generate androgens and female hormones.

When I started studying pathology, prostate cancer was rarely seen in the prime of life, and the majority of cases were seen in elderly people by chance at autopsy. Under these circumstances, the small prostate cancer is called occult cancer or latent cancer. On the other hand, nowadays in Japan, prostate cancer in young patients was seen infrequently, but of those, most progressed very rapidly, then metastasized and were fatal.

There is a highly suggestive report that was released in the early 80s. This research was conducted on white and black males in the US, Colombians, and Japanese (living in Hawaii or Japan). These patients died from causes other than cancer, and were autopsied so that their potential prostate cancer could be examined carefully.

In each group, the number of cases with potential prostate cancer was almost same, but fatal cases were seen more significantly in black males in the US group, then white males in the US group, which was followed by the Columbian group, Japanese men in Hawaii, and Japanese men in Japan respectively.

These results indicate two facts. Prostate cancer can be divided into two groups; one is moderate cases which are common all over the world, and the other is more malignant cases that are influenced by external environments, including dietary habits and food selection.

Significant external influences that affect prostate cancer developments are the following: 1) the amount of vegetable and fruit consumption for antioxidant properties, 2) consumption of fat, specifically the amount and type 3) degree of consumption of soy products and 4) amount of fish and sea vegetables that are consumed.

The report by the National Cancer Institute of the US in 1998 shows that regarding prostate cancer morbidity, Japanese and Chinese males are among the lowest cohorts and American males are among the highest. In particular, the prostate cancer morbidity rate of black males in the US was about 13 times higher than that of Japanese males. As I mentioned, epidemiological research indicated that the prostate cancer morbidity of Japanese males rapidly increases after moving to North America. Considering these facts, we can theorize that eating habits may greatly affect the development of prostate cancer.

Research results show that the consumption of beef and meat, fatty foods, and too much calcium raise the risk of developing prostate cancer. A researcher in New Zealand studied the relationship between prostate cancer morbidity and methods of cooking beef, pork and chicken, and the amount of heterocyclic amines contained in the burnt portions of grilled foods. It turned out that men who eat grilled beef steaks that were burnt are at higher risk of prostate cancer than non-burnt meat. Chicken is least likely to cause prostate cancer. Meat with fat tissue is needed to be digested with larger amount of bile for suspension. Bile secreted in the gut might be altered to be carcinogenic by intestinal flora by chance so that such a substance must be dangerous to the colon mucosa and also must be absorbed into the blood to any excretory glands such as the prostate, breast or pancreas.

Additionally, dietary fiber is helpful to prevent not only breast cancer, but also prostate cancer. In the following I will discuss some other health promoting foods.

Lycopene

Lycopene, a carotenoid (red pigment), along with other materials found in tomatoes, have shown preventive effects against prostate cancer in animal experiments. Lycopene is an antioxidant and is effective for preventing other cancers as well.

BioBran, extracted from rice bran, is also antioxidant, and is expected to have immunomodulatory functions along with those of an antioxidant.

Dr. Pfeifer, a distinguished oncologist in Aeskulap Clinic in Switzerland，uses BioBran as one of the methods to treat progressing prostate cancer which is androgen receptor-negative. Those cancers are the most treatment-refractory ones in prostate cancer, and tend to be resistant to anticancer drugs. It has been gradually discovered that we can find nutrients that fight against cancer from natural sources, such as tomatoes and rice bran.

Soy Bean

Many epidemiological studies show that the low prostate cancer morbidity of Japanese males is mainly attributed to their large consumption of soy bean products. Soy bean contains lignans (dietary fiber), isoflavones (phytoestrogen), and other phytonutrients, such as saponins. Lignans are also present in whole- grain bread, sesame seeds and various other seeds, berries (strawberry, blueberry and others), vegetables, and green tea. As I mentioned previously, androgen promotes growth of prostate cancer cells and female hormones inhibit canceration of prostate epithelial cells. It is indicated that soy phytoestrogens may also inhibit canceration of prostate cells.

Genistein, one kind of isoflavone, not only has antioxidant effects, but also sets the function of Epidermal Growth Factor Receptor (EGFR) to “OFF”. It has been reported to reduce arterializations and be involved in growth factor (TGFβ). Refer to previous descriptions about soybeans and breast cancer for more detailed information.

A research study conducted on 8,000 Japanese Americans living in Hawaii reported that prostate cancer morbidity was the lowest in the group of men who consumed a lot of tofu (soy bean cake). In the comparison to the isoflavone volume in the blood between Japanese males and Finnish males, who show higher prostate cancer morbidity, Japanese males showed 7-110 times higher levels.

It has been shown that soy isoflavones may reduce prostate cancer. Soy isoflavones help us maintain good health, because they are effective not only for prevention of prostate, breast, and large bowel cancer, but also reduce brain, heart and blood vessel diseases by reducing cholesterol levels in blood. But soy also contains unhealthy components. A study shows that animals that consumed a lot of raw soybeans developed pancreas cancer, caused by trypsin, a digestive enzyme inhibiter. Soybeans should always be well-cooked.

Omega-3 unsaturated fatty acid

A research study was conducted in Sweden involving twins who were born between 1886 to 1925, and questionnaires were given to them between 1961 and 1967. In follow-up research, the relationship between prostate cancer morbidity and age, degree of obesity, eating habits (consumption of beef, pork, smoked meat and ham, fruits, and vegetables), smoking history, drinking history, sedentary work, lifestyle, exercise, and others parameters were evaluated.

This follow-up research was conducted on 6272 persons with an average age of 50, for up to 30 years after (average research period was 21.4 years). During this research period 466 men developed prostate cancer, and 340 of them died because of it. In the group of people who ate fish more frequently, exercised, abstained from smoking, and ate a lot of vegetables and fruits, they showed a lower morbidity rate of prostate cancer. The specific kinds of fish were mainly cold-water fish, such as herring, salmon, and mackerel, which contain abundant omega-3 fatty acids.

But the group of people who rarely ate fish showed two- to- three times higher morbidity than the previous group. The consumption of fish caused a significant difference in prostate cancer morbidity. This fact didn’t change after being modified for genetic factors in twins or lifestyle habits.

Similar results have been reported recently, one after another. Omega-3 fatty acids found in fish oil are recognized for reducing growth of androgen-receptor positive prostate cancer cells, dose dependently. This function seems to have no relation to whether a patient has androgen receptors or not, and effects DNA directly.

Based on these results, a study was conducted on patients with untreated prostate cancer. Patients were given low-fat meals supplemented with fatty acids, with a high proportion of omega-3 and omega-6 for three months. Patients were followed with genetic testing, erythrocyte membrane fatty acid analysis, adipose tissue biopsy from the lumber region, histopathological analysis of prostatic biopsy, and cyclooxygenase (COX-2) levels. Regarding the fatty acid analysis of fat and red blood cell membranes, omega-3 levels were shown to increase rapidly. Histopathological pictures improved, and COX-2 decreased. These results indicate that reducing COX-2 levels helps to reduce prostate cancer, as with colon cancer, which may be due to omega 3 fatty acids.

Alpha-linolenic acid

An epidemiological study comparing health status and dietary patterns specific to a country or region shows that the morbidity of prostate cancer is correlated with the total amount of fat contained in meals and the consumption of saturated fat. This research is helpful to find indirect carcinogenic factors. It has also been shown that increased consumption of omega-6 derived from animal fat is also related to a higher risk of prostate cancer.

I mentioned in the previous section that omega-3 fatty acids found in fish oil may reduce the risk of developing prostate cancer. Those researchers have been influenced by the fact that morbidity of prostate cancer is low among Japanese and Inuit. A large-scaled study of 50,000 people who took a questionnaire, were followed over a four year period. People were segregated into two groups, one that developed prostate cancer and a group that didn’t, and their eating habits were studied. The results indicated that alpha-linolenic acid, an essential fatty acid found in plants rather than fish, was shown to be correlated with an increased risk of prostate cancer, which is admittedly contrary to conventional wisdom. Further research should be done, although a second study reported similar findings.

In Uruguay, South America, morbidity of prostate cancer is high, followed by that of lung cancer, and 35.2 people per 100,000 in the population will develop this disease (1990-1992). The reasons implicated are high beef consumption and alpha-linolenic acid consumption. Five of six studies, which have been reported recently, conducted additional tests and reconfirmed the relationship between alpha-linolenic acid and the rising morbidity of progressing prostate cancer. We do need to acknowledge these results.
In conclusion, it is recommended to consume less meat that is “burnt”, less beef and pork, and increase intake of fish and olive oil. But omega-6 and alpha-linolenic acids that are found in vegetable oil should be consumed in moderation.

Compared to North America where the main sources of oil are extracted from soybean or rapeseed, the olive oil-consuming region around the Mediterranean Sea shows relatively lower morbidity rates of prostate cancer. It has been reconfirmed that olive oil is one of the healthiest oils out of the many available varieties. Alpha-linolenic acid is contained in mayonnaise, store-bought salad dressing, margarine, butter, beef and pork. Habitual intake of those foods may enhance the risk of developing prostate cancer. It is important not to consume excess amounts of vegetable oil sourced from salad dressing.

Soy products, garlic, and fish are recommended as part of a healthy diet. Tomato sauce and tomato puree are better than fresh tomatoes. Tomato ketchup may be a good second choice. It is good to take garlic, vitamin D, vitamin E, and a small amount of selenium (a trace mineral). Absorbable forms of calcium should be taken moderately. Beef and pork, especially when burnt, should be avoided.