Prostate cancer is an excellent type of tumor to perform chemoprevention strategies, due to its high incidence and its appearance in advanced ages.
Any delay in the carcinogenesis of prostate cancer could lead to a decrease in its incidence. Similarly, the presence of premalignant lesions may serve as the target of such chemo-prevention. A timely diagnosis by the urologist can be key.
Nutrition and prostate cancer
Scientific evidence on mortality and incidence of prostate cancer suggests that environmental factors influence its appearance and development.
Also, some nutritional factors have also been linked to the increased risk of developing prostate cancer, especially high consumption of animal fat and dairy products.
In contrast, there are nutritional factors that have a lower incidence in prostate cancer. They are observed, especially, in populations that consume more selenium, vitamin E, fruits and tomatoes.
There are some hormonal agents related to prostate cancer.
Testosterone, once found inside the prostate cell is metabolized by 5 alpha reductase. This enzyme occurs in the body in the form of two iso-enzymes (type 1 and 2). Finasteride is a selective inhibitor of type 2 enzyme, whereas Dutasta- ride inhibits both types.
- Finasteride. In a 7-year study comparing the effect of finasteride versus placebo, we found a higher prevalence of prostate cancer in the finasteride group compared to the placebo group. This represents a significant reduction of risk between the two treatment groups. In addition, an absolute reduction was observed in patients treated with Finasteride regardless of whether it was detected by a biopsy of the cause at the end of the study.
- Dutasteride. The incidence of prostate cancer in patients receiving Dutasteride was less than half the incidence in patients assigned to the placebo group.
Oxidative stress is one of the factors that promote carcinogenesis. Oxidation of tissue can lead to genetic mutations that cause cancer. For this reason, it is believed that antioxidants can be preventative in several types of tumor. The most used are:
- Vitamin E. It has a high antioxidant and antiproliferative capacity. It is found in vegetable oils, nuts, avocados, eggs and cereals. The recommended daily dose is 15 mg and it is not recommended to exceed 95 mg daily. Also, it is recommended to suspend consumption 10 days before a biopsy, radical prostatectomy, brachytherapy or cryotherapy, since vitamin E is a platelet antiaggregant.
- Selenium. The concentration of selenium depends on the content on the land where the product was grown. It is found in meat, grain cereals and seafood. The recommended daily dose is 0.87 μg / kg and the tolerable limit is 400 μg / day for 7 years. Several studies have shown that selenium supplementation inhibits the growth of prostate cancer cell lines, both sensitive and resistant to androgens.
- Lycopene. It is a very powerful antioxidant of the carotenoid family found in high concentrations in tomatoes, which give the color red, and in the products derived. As it is not an essential nutrient there are no recommendations on the amount of daily consumption although it is suggested consumption of 5 measures of tomato or derivatives per week as part of a healthy diet. In an "in vivo" study the association of tomato and broccoli was more effective in reducing tumor growth than consuming them separately.
- Green Tea. Tea contains many polyphenolic compounds, with epigallocatechin gallate (EGCG) being the most studied. Its mechanism of action has not been determined but is believed to work through the inhibition of proteolytic enzymes that prevent metastasis, antiangiogenesis and act in intercellular communications. A clinical study demonstrated the efficacy of green tea catechins with only a 3% incidence of prostate cancer in patients treated with it compared to an incidence of 30% in patients treated with placebo.
- Soy and Isoflavones. The use of soy products in the prevention of prostate cancer is based on the same principle as the use of green tea and is that in Asian countries, where consumption of soy and isoflavones is high, the incidence of cancer of prostate is low. The diet of Asian countries includes 10 times more soy products than those consumed in the western diet. Recently a meta-analysis has been carried out which has estimated that the relative risk of prostate cancer in patients with high soy consumption is lower than in subjects who do not consume it.
- Pomegranate. Grenadine juice and its extract have demonstrated a great antitumor effect in patients with prostate cancer. A University of California study tested the effectiveness of pomegranate juice, which increased PSA doubling time by up to 6 months. In fact, several studies have shown that pomegranate juice causes the death of hormone-resistant prostate cancer cells and also increases cell adhesion and decreases cell migration.
- Supplements rich in polyphenols. A clinical study conducted at the University of Cambridge showed that treatment of prostate cancer patients with extract of pomegranate, broccoli, green tea and turmeric delayed the progression of cancer compared to patients who were treated with placebo. After 6 months, in the group of patients treated with capsules with the dietary supplement the mean PSA rose, whereas in the non-placebo group.
- Non-steroidal anti-inflammatory drugs. There is evidence that prostaglandins are involved in the development of various cancers. The cyclooxygenase (COX) of which there are two isoforms (COX1 and COX2) is a very important enzyme in the synthesis of prostaglandins. COX2 manifests itself in high concentrations in several tumors including prostate cancer. For this reason, non-steroidal anti-inflammatory drugs and selective COX-2 inhibitors (Rofecoxib, Celecoxib, Exisulind, etc.) appear as potential agents in the prevention of prostate cancer because they decrease the synthesis of prostaglandins. Several studies on the effects of aspirin on the risk of developing prostate cancer have detected a contrary relationship.
- Coffee. It has recently been observed that consumption of 4 cups of coffee per day was associated with a lower risk of prostate cancer compared to patients taking less than one cup daily.
- Physical exercise. The University of Rochester demonstrated that physical exercise reduces the production of interleukin 6 (IL-6), which is produced by depression and inflammatory processes, which means the reduction of prostate cancer progression. Patients receiving conventional treatment with radiotherapy or hormone block showed an increase in IL-6 production, while patients who were also treated with a physical exercise program showed a decrease in IL-6. Similar results were observed with interleukin-8 (IL-8).