Introduction – What you will learn from this article
You will often read or hear nowadays about prostate on media. What is prostate, what is the function of prostate and how and what does it look like to have a medical condition of prostate? This text is meant as a reference for all those questions you had and did not know you had them. Onwards, you will find basic information about prostate as an organ, its function, what are common symptoms of prostate issues, what can be the cause of prostate problems, what are treatment options for these problems. How do stress, age and other factors play a role in changes in prostate, and how does it affect your health?
Amongst many subjects we will also brush up on your knowledge on prostate cancer. We will try to give answer on how to test for prostate cancer, what are warning signs of prostate cancer, as well as treatment options available from surgical to other much less complex means of managing this disease.
Lastly, there will a part about prostate testing, and what methods are available for testing prostate health as well an explanation what is the objective of these tests and what information can they tell you.
What is the prostate?
Prostate is a gland which is exclusively part of men reproductive system. It is positioned in pelvis below the bladder and in front of rectum. Size of the prostate is around the size of walnut, and weighing between 7-16 grams. It surrounds urethra, a tube which connects urinary bladder with external urinary orifice. (1)
Being in that close relation with urethra means it can excrete its products in it. So what does prostate actually do? It synthesizes alkaline fluid which composites around 30% of semen and is important for improving chances of spermatozoa reaching and fertilizing egg cell. This fluid is used to combat acidic environment of vaginal tract and also improves mobility of spermatozoa.
One thing that is important from the aspect of prostate disease is that prostate is divided by doctors into zones. There are four zones which take up different amount of total prostate volume. Listed below are zones with their share of total volume:
- Peripheral zone (PZ)- makes up around 70% of the gland in young men
- Central zone (CZ)- approximately 25%
- Transition zone (TZ) – around 5% during puberty
- Anterior fibro-muscular zone (or stroma) – around 5% (1,2)
With this prostate also can be sensitive to stimuli in some men and cause ejaculation if stimulated. Prostate and its function are regulated by a hormone which gives male sex their characteristics- testosterone. To put it simply prostate gland functions as an important part of male reproductive system in close relation to urinary system.
There are only three diseases which are frequent enough to discuss. These are:
- Benign enlargement of prostate or benign prostate hyperplasia
- Inflammation of prostate or prostatitis
- Prostate cancer
Benign enlargement of prostate or benign prostate hyperplasia
This condition is quite common amongst men older than 50 years of age. Prostate as the name suggest gets enlarged and presses on the structures surrounding it, mostly affecting urethra. BPH as it’s called shortly is the most frequent cause of lower urinary tract symptoms (LUTS) in ageing man. Much like when you bend a garden hose, prostate causes urinary tract to narrow and mentioned symptoms. (3)
These include many symptoms such as poor stream, increased frequency of urination and excessive urination at night. Like mentioned, age plays a huge factor in BPH. Some epidemiological data suggest that BPH can be found in 8% of men in their forties while in the 9th decade as much 60% of men have BPH. (4) Other factors that are frequently mentioned are:
- Diet : red meat, increased calorie intake, fat, dairy products potentially increase the risk of BPH
- Lack of physical activity
- Erectile dysfunction
- Inflammation of prostate(4)
Mechanism of this disease is still in debate but it is generally considered that it lies in sensitivity of prostate cells to testosterone. Testosterone is turned into dihydrotestosterone (DHT) in the prostate by an enzyme. Prostate cells are sensitive to DHT which induces their growth. This means that prostate can grow even in old age. (2)
Text to use under picture:
Picture 1. Normal vs. enlarged prostate
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Inflammation of prostate or prostatitis
Prostatitis describes a variety of causes that ultimately causes an inflammation of prostate tissue. This is not to be confused with epididymitis which is an inflammation of another part of reproductive system. Most common type of prostatitis nowadays is chronic abacterial prostatitis. (2)
Apart from this it can also appear in chronic and acute bacterial form. Prostatitis can be due to infection with different bacteria or with no apparent culprit. Epidemiological findings report that around 8,2% people involved in research expressed various criteria for diagnosing prostatitis.(5)
This number is really high in context that this condition is related to increased risk of BPH, prostate cancer. (5) How do you get prostate infection? There are many risk factors and they are different for different types of inflammation. Risk factors for acute prostatitis include:
- Recent urinary tract infections
- Having an urinary catheter
- Injury to pelvis
- Having HIV or AIDS
- Having a sexually transmitted disease
- Having a recent prostate biopsy
- Anal sex (6)
As for chronic prostatitis risk factors are as follows:
- Being between 30-50 years of age
- Previous episodes of inflammation
- Having other painful abdominal conditions such as irritable bowel syndrome
- Sexual abuse (6)
Prostate cancer is a malignant enlargement of the gland which can lead to serious health issues or even death if untreated. Basis of prostate cancer is identical to every other type of cancer. DNA in cells starts to mutate causing cells to grow abnormally and uncontrollably.
It usually develops in older age with highest incidence in men older than 75 years of age composing around one third of prostate cancers diagnosed in UK. (10) It rarely affects people younger than age of 50. However, prostate cancer screening is recommended for men above age of 40 if they are at an increased risk. (2) Testosterone plays an important part in prostate cancer genesis as prostate cells are sensitive to this hormone but scientific data is inconclusive as to how much of an impact testosterone has. Like benign enlargement and prostatitis, cancer has risk factor associated with it but this will be further discussed below.
Table 1. Prevalence percentage for BPH (3), prostatitis (using the National Institutes of Health chronic prostatitis symptom index) (13), and probability for developing prostate cancer in relation to age (9)
Symptoms and signs of Prostate cancer
Prostate cancer symptoms and signs mimic those of BPH and prostatitis. Early prostate cancer doesn’t usually present with any symptoms or signs. So, when they appear it is always wise to resort to testing and doctors help. However, symptoms of prostatitis can be very different from those of BPH and cancer, but like with them it is always wise to refer to doctor if you experience any of the things mentioned here.
Table 2. BPH, prostatitis and prostate cancer symptoms in men and differences (14,15,16)
*prostate cancer symptoms not found in BPH and prostatitis
Prostate cancer stages and prevalence
Prostate cancer is the single most diagnosed cancer in male population comprising 26% of all newly diagnosed cancers in male population in UK. (7) 1 in 9 men in the US and 1 in 8 men in Canada will be diagnosed with the disease during their lifetime. (8,9) These are shocking prostate cancer facts, which put a real perspective on how dangerous prostate cancer is.
Age plays a significant factor in cancer development as shown in the table below with age above 55 being more at risk for developing cancer than younger. It is most frequently diagnosed in men aged between 65 and 74. (17)
Table 3.Percent of new cases by age groups (17)
For now, only well-established risk factors are age, male sex, positive family history for prostate cancer, and certain genetic markers according to International Agency for Research on cancer (IARC). So, what are other risk factors? Listed below are risk factors for prostate cancer:
- Ethnicity– prostate cancer is more common in black- African men, than in Caucasian or Asian men
- Genetics or family history of prostate cancer – BRCA 2 gene increases risk of prostate cancer 5 times
- Being overweight or obese
- Height – taller man have higher risk of developing cancer of prostate by some research
- Personal history of previous cancers of kidney, bladder, lung, thyroid or melanoma
- Higher concentration of hormone called insulin growth factor 1 (IGF-1)
- Cadmium poisoning (10)
- Smoking- considered to be a risk factor by some research
- Diet – red meat and high fat dairy products in combination with less fruit and vegetables in diet are potential risk factor (11)
- Professional exposure to pesticides increases risk 13-24% (19)
- Sexually transmitted infections like chlamydia or gonorrhoea might increase risk because they can lead to prostate inflammation (19)
- Abuse of anabolic steroids is also suspected to increase risk of prostate cancer(19)
- Sedentary lifestyle
Table 4. IARC list of risk factors related to prostate cancer
Other risk factors for prostate cancer
Masturbation and prostate cancer have been linked in a couple of studies. As part of studies from 2003 and 2004 it was shown that those men who ejaculate for at least 21 times a month lower the risk of prostate cancer about 33% (12).
Levels of testosterone in relation to prostate cancer have been always a point of interest for researcher, but to this day no solid evidence was presented to prove it (18).
Also rubber production is mentioned as possible risk factor by International Agency for Research on Cancer (19). Cyclist above the age of 50 are at potential risk which is dose related to development of cancer. More hours on bicycle spent weekly means risk for prostate cancer is increased (20).
One other important thing in cancer genesis is heredity. If you have positive family history of prostate cancer, there is a chance that you inherited genes that are connected with higher risk of developing prostate cancer throughout life.
Table 5. Genes with higher risk of developing prostate cancer and other types associated with them (23, 24)
Staging and grading prostate cancer
Nearly all prostate cancers diagnosed are adenocarcinoma. That means that cancer forms from gland cells that line prostate. Other types are rare and they are:
- Ductal cancer – forms in the tubes which lead the fluid from secreted from prostate to urethra
- Transitional cells cancer- forms in urinary tract at first but spreads to prostate
- Squamous cell- develops from cells that cover the prostate
- Small cell cancer- made up of small round cells
- Sarcoma- formed from connective tissue
- Carcinoid- formed from neuroendocrine tissue (25)
Text to use under picture:
Picture 2. Prostate cancer microscopic structure
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Grade of cancer looks at how much cancer cells look like normal cells. Grade defines for doctors how cancer behaves and what are best treatment options for prostate cancer.
Other tool in disposal is staging. It tells how big cancer is and how much it is spread in the body. It looks at local spread, through lymph nodes, and possible metastasis. These measures can in turn form a prognosis for prostate cancer and help doctors decide on optimal treatment. (25)
Another way of estimating danger from cancer is dividing them by three stages:
- Local – cancer didn’t spread out of prostate (it can include stage I, II or even III)
- Regional – cancer did not spread out of local area (mainly includes IIIB and IVA stages)
- Distant- cancer has spread to distant areas of body (mainly IVB stage)
Where does prostate cancer spread?
Prostate cancer is all the more dangerous because it can metastasize in different areas of the body. Regions particularly in the risk are bones, mainly pelvis and spine, than brain and lungs.
Detection and symptoms of prostate cancer
Symptoms of prostate cancer in men are mentioned above in detail. But it is important to stress that early prostate cancer can give no symptoms or signs. This leaves us with the question how do you know if you have prostate cancer? It is recommended to test your prostate health if you have any of the risk mentioned above. That leaves us with the question how to test for prostate cancer?
Prostate cancer testing options
Most important test that you can do are PSA antigen testing, prostate exam, transrectal ultrasound, biopsy of prostate which are done by doctor. Prostate exam is meant to give doctor the picture of the size and consistency of prostate. This can give valuable information and set as suspicion for further testing.
It is a good starting point along with taking medical history; however exam can be uncomfortable as doctor needs to palpate the prostate through anus where it rest on rectum. Other good test is ultrasound but again this test needs to be done through anus and in the rectum.
Text to use under picture:
Picture 2. Prostate rectal exam
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Depending on the results of the test before, doctor may suggest some imaging methods like CAT scanner, magnetic resonance or bone imaging for detecting metastasis. Biopsy is surgical procedure which analyzes a tissue sample taken from prostate. Its purpose is to determine grade and type of cancer.
PSA antigen is compound that is found in blood and is produced by prostate cells in healthy and diseased prostate. It is a simple blood test that you can do from home. Results of test are measured in nanograms per millilitre of blood (ng/ml).
This test is primarily used for cancer screening in men that don’t have symptoms, or started showing symptoms. It can also be used as reference for how well treatment has been going in people diagnosed. High PSA count can mean that cancer is present but the results need to be approached carefully as other conditions of prostate can present with high level of PSA in blood. (26)
PSA testing results and what to do
There is no normal value for PSA levels. It depends on age and tends to get higher as you get older. If there you have abnormal level of PSA for your age your doctor may refer you to further testing to clarify the reason why. Sometimes normal level for your age doesn’t mean that there is no cancer present.
It is generally considered that have PSA levels under 4ng/ml have no prostate cancer. This is not a 100% guarantee as 15% of men with levels below 4 who had biopsy had prostate cancer. People with results between 4-10 ng/ml have 1 in 4 chance of having prostate cancer. This chance goes up to 50% with levels beyond 10 ng/ml.
Doctors may opt for biopsy if levels are higher than 4 ng/ml, but also other risk factors must be taken in considering before deciding for this. (26)
Very high PSA levels usually mean that cancer is spread through body and that immediate further diagnostic and treatment plan are needed.
Home tests for prostate cancer
There is a wide range of tests that you can do from home to test for prostate cancer. If you want to find out if you have genes which are connected with higher risk for prostate cancer you may opt for BRCA or other genes testing. These are simple test requiring saliva which analyses presence of gene mutations in cells from sample.
PSA home tests and other blood tests
Other type of testing is for PSA levels in blood. These tests are meant to easily and without invasive measures track for possible changes in your prostate before or when symptoms show up. People after age of 40 with risk factors for prostate cancer are recommended to test for PSA levels can be tracked. Some tests can only give information if the levels are above 4ng/ml but don’t give precise count, while others are much more sophisticated and measure levels precisely.
Another type of test is prostate cancer is prostatic acid phosphatase (PAP). This parameter can be used in combination with PSA if there PSA levels are normal and can be a sign of cancer. Both of these parameters can be used in treatment management.
It is important to have in mind that when estimating results certain conditions or things you do might elevate results you get. These are:
- Ejaculation within 48h from testing
- Prostate massage
- Participating in vigorous exercise
- Ride a bike, motorcycle or a horse
The best PSA and prostate cancer tests
Treatment of prostate problems
BPH treatment depends on severity of symptoms. Main things that can be done are:
- Lifestyle changes
Drinking less alcohol, fizzy drinks, caffeine and artificial sweeteners is good way to start. It is also recommended to drink less in the evening and improve diet to include more fibre and fruits. Emptying bladder and training to hold more urine is also proven to be helpful.
These are used if lifestyle changes don’t yield any results. Your doctor can offer you a variety of medicine which will personally suit you best.
If you have trouble emptying bladder your doctor may suggest a catheter to ensure that outflow is optimal.
- Surgical procedure for prostate enlargement
There are many surgical options which can be used for treating this problem like prostate artery embolization, prostate resection trough urethra etc. (27)
Treating prostatitis is similar in concern of lifestyle changes, but medications include anti-inflammatory drugs and antibiotics if there is need for it.
Self-treatment of prostate problems
Another huge problem related to prostate problems is erectile dysfunction. What is erectile dysfunction? It is a condition where penis erection cannot be maintained or achieved to have sexual intercourse. Reasons for what causes erectile dysfunction are numerous and they can be due to cardiovascular disease, stress, anxiety, relationship problems, obesity or abuse of substances such as alcohol, tobacco, drugs, medications and etc.
Depending on the cause erectile dysfunction cures vary and can include different ways of treatment. To answer question is erectile dysfunction reversible, you must look at the main problem causing it.
How to cure erectile dysfunction at home
To fix erectile dysfunction naturally you can resort to losing weight, reducing stress and anxiety, reduce or stop smoking and substance abuse, exercise daily and eating more healthy diet. You should avoid riding bicycles. Other erectile dysfunction cures are vacuum pumps which are used to achieve erection and are proven to help many men, reaching out to counsellor for psychological support, or using medications such as syldenafil (Viagra). (28)
Treatment of prostate cancer
Planning for treatment starts when all aspects of cancer are analyzed. Biopsy and imaging methods are used to get the whole picture, location, spread and type of cancer. When these parameters are determined treatment is decided between team of doctors which are specialized to treat cancer to the best of available options. Treatment is ideally planned to suit individual needs and requirements of patients and according to their diagnosis and general health and fitness.
Treatment options for prostate cancer are:
- Surgery – main goal is to remove prostate gland, but also lymph nodes at risk and portions of organs around prostate can be removed; other interventions are removing part of prostate to alleviate symptoms or testicle removal to control cancer spread
- External radiotherapy
- Internal radiotherapy
- Hormone therapy – surgical castration to stop testosterone production, and medication that lowers levels of testosterone such as abirateron (Zytiga)
- Symptom control treatment
- Cryotherapy or high frequency ultrasound therapy as part of a clinical trial where available (29)
- Biological (immune) cancer therapy through medical trials
- Bisphosphonate for bone disease when cancer metastasizes in bones
Side effects of prostate cancer therapy
Like every treatment that is aggressive and uses dangerous methods side effects of prostate cancer treatment are many and sometimes require more energy, time, resourcefulness to combat.
Maybe most known are side effects of prostate removal. After the procedure is done and risk of unexpected reaction to anaesthesia, bleeding that cannot be stopped, blood cloths forming, and etc. In the long run there is danger of erectile dysfunction and urine incontinence.
Side effects of chemotherapy are many and include loss of hair, nausea and vomiting, diarrhoea, fatigue, loss of appetite, increased chance of infections and etc.
Hormone shots or medications for treatment are used to lower level of testosterone and other androgen hormones and stop prostate cell proliferation. Side effects of this therapy is loss of libido, breast growth and tenderness, penis and testicles shrinkage, anaemia, fatigue, weight gain, erectile dysfunction and etc.
Is prostate cancer painful?
Prostate cancer can be painful if it spreads to structures like bones, or segments of highly innervated areas or if the size causes compression symptoms.
Table 6. Treatment options according to spread and stage of prostate cancer (29)
Treatment of prostate cancer is proven to have good results in early stages and solid results even in the later stages. Life expectancy of prostate cancer survivors is quite high and most people live out fulfilling and full life.
Table 7. 5 year relative survival rates of different stages of prostate cancer (30)
As much as 80% of all prostate cancers diagnosed are discovered in the local stage. This means that 5 year relative prostate cancer survival rate is really good, and these patients recover fully from their disease. Overall prognosis for prostate cancer for people at this stage and regional stage is excellent.
First two stages of this classification can include even stage 3 prostate cancer so that means that even more aggressive and advanced aspects of cancers respond well to treatment. That means not only their 5 year relative survival rates are good, but also 10 and 15 year relative survival rates are really good. Reason that distant stage has a notable lower level of 5 year relative survival rate is that the cancer is spread to many far structures which don’t respond to treatment well or therapy can do more harm than benefit. (30)
After treatment and success life can be continued with normal activities suggest by doctors but patients need to be careful for it to not return. In discussion with doctors, best follow up plan can be devised, and actions taken to assure that normal and otherwise fulfilling life can be led.
Reducing risk of prostate cancer and self-treatment of prostate cancer
Best measure against any disease is prevention. With prostate cancer this is also the same. There are medically approved, experience proved and evidence based ways to lower chances of getting prostate cancer. They basically are concentrated around improving overall health of individual and avoiding risks related to developing not just prostate cancer but also cancer in general.
- Eating at least 2 and a half cups of wide variety vegetables and fruits
- Being physically active
- Staying at healthy weight range
- Avoiding exposure to risks connected to prostate cancer if possible
Until recently food containing lycopene (tomatoes and other red fruits), selenium (Brazil nuts), and vitamin E and soy products are thought to lower risk of developing prostate cancer. Scientists at World Cancer Research Fund have looked at numerous studies and results of these are not clear on the connection between the two. Aim to avoid eating too much dairy and milk, but keep in mind not to completely exclude it from your diet as you need to ingest 700mg of calcium daily. Also try avoiding red meat as it is suspected to increase the risk but it is not proven whether this lowers the risk. (31)
It is quite normal that you would want to find ways to enforce therapy prescribed by doctors. Lot of people on chemo try this by using vitamins to boost immune system and organism as a whole. But this can have an opposite effect as vitamin A, C, E act as antioxidants and that can interfere with medication efficiency. (32)
There were few case reports that fasting during chemotherapy could enhance the effects of therapy. However, these are individual cases and scientists have started to study this method in hope they will find a reliable and explainable results and a proposed mechanism behind this. To this day, no certain evidence is provided. (33,34)
Studying relation between omega 3 fatty acids and prostate cancer development is new area researchers are trying to find a link. For such research to give answers that are relevant and evidence based, a lot of money, time, and data need to be gathered. For now, no link has been found in couple of studies but nevertheless an advice on avoiding omega 3 rich foods is given. (35,36)
Studies with other drugs like oxaloacetate, glutamine, ketogenic diet and diabetes drugs like metformin have been done to determine their effectiveness in prostate cancer therapy. These have not given clear results, although promised mechanisms of effect give hope that in future with more focused and well-funded research these methods could be incorporated in treatment and make a huge difference. (37, 38, 39)
Table 9. Methods for boosting immune system, lowering risk for prostate cancer and additional support to therapy (31-39)
Although a small part of our body, prostate problems are a complex problem for which are developed numerous diagnostic and therapeutic methods, and many more are researched. Looking out for prostate health especially in older age is a responsible, sensible way to ensure that problems which can lead to much unease and stigma be avoided.
Making sure that you test regularly may ensure that these problems are caught in early stages and therefore don’t leave such extreme consequences which can have a huge psychological impact and cause much distress in future.
1. Unknown author, unknown date, Prostate, Wikipedia, https://en.wikipedia.org/wiki/Prostate
2. Vinay Kumar, Abul K. Abbas, Nelson Fausto, and Jon C. Aster, 2010.,Robbins and Cotran: Pathologic Basis of Disease, 8th Edition
3. Kok Bin Lim, 07.2017, Epidemiology of clinical benign prostatic hyperplasia, Asian Journal of Epidemiology, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5717991/
4. Unknown author, unknown date, Prostate Health & Disease, Harvard Health Publishing (Harvard medical school), https://www.health.harvard.edu/topics/prostate-health-and-disease
5. Krieger JN, Lee SW, Jeon J, Cheah PY, Liong ML, Riley DE, 02.2008, Epidemiology of prostatitis, International Journal of Antimicrobial Agents, https://www.ncbi.nlm.nih.gov/pubmed/18164907
6. NHS editorial team, unknown date, Prostatitis, NHS https://www.nhs.uk/conditions/prostatitis/
7. Cancer Research UK, 23.01.2018, Cancer incidence for common cancers Cancer Research UK, https://www.cancerresearchuk.org/health-professional/cancer-statistics/incidence/common-cancers-compared#heading-One
8. Prostate Cancer Canada, unknown date, Prostate Cancer, http://www.prostatecancer.ca/Prostate-Cancer/About-Prostate-Cancer/Prostate-Cancer
9. Rebecca L. Siegel, Kimberly D. Miller, AhmedinJemal, Cancer statistics 2018., CA a cancer journal for clinicians, https://onlinelibrary.wiley.com/doi/10.3322/caac.21442
10. Cancer Research UK, 30.05.2015, Risks and causes, Cancer Research UK, https://www.cancerresearchuk.org/about-cancer/prostate-cancer/risks-causes
11. American Cancer Society editorial team, 11.03.2016, Prostate Cancer Risk Factors, American Cancer society, https://www.cancer.org/cancer/prostate-cancer/causes-risks-prevention/risk-factors.html
12. Marc Garnick, M.D., 04.2009, Does frequent ejaculation help ward off prostate cancer?, Harvard Medical School, https://www.cancer.org/cancer/prostate-cancer/causes-risks-prevention/risk-factors.html
13. Nickel JC, Downey J, Hunter D, Clark J, 03.2001., Prevalence of prostatitis-like symptoms in a population based study using the National Institutes of Health chronic prostatitis symptom index, The Journal of Urology, https://www.ncbi.nlm.nih.gov/pubmed/11176483
14. Mark Litwin, M.D., Anthony Schaeffer, M.D., Michael P. O’Leary, M.D., M.P.H,07.2014., Prostatitis: Inflammation of the, National Institute of Health, https://www.niddk.nih.gov/health-information/urologic-diseases/prostate-problems/prostatitis-inflammation-prostate
15. Cancer.Net editorial board, 03.2018., Prostate Cancer: Symptoms and Signs, Cancer.Net, https://www.cancer.net/cancer-types/prostate-cancer/symptoms-and-signs
16. Unknown author,31.03.2017.,Benign prostate enlargement symptoms, National Health Services (NHS), https://www.nhs.uk/conditions/prostate-enlargement/symptoms/
17. National Health Institute, Unknown date, Cancer Stat Facts: Prostate cancer 2011-2015, National Health Institute, https://seer.cancer.gov/statfacts/html/prost.html
18. Klap J, Schmid M, Loughlin KR, 02.2015., The relationship between total testosterone levels and prostate cancer: a review of the continuing controversy, The Journal of Urology, https://www.ncbi.nlm.nih.gov/pubmed/25260832
19. Cancer Research UK, Unknown date, Prostate cancer risk factors, Cancer Research UK, https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/prostate-cancer/risk-factors#heading-Zero
20. Bazian, 09.07.2014., Cycling linked to prostate cancer, but not infertility, National Health Services NHS, https://www.nhs.uk/news/cancer/cycling-linked-to-prostate-cancer-but-not-infertility/
21. The prostate cancer working group, unknown date, Prostate cancer, International Agency for Research on Cancer, http://epic.iarc.fr/research/cancerworkinggroups/prostatecancer.php
22. Unknown author, 30.01.2018, BRCA Mutations: Cancer Risk and Genetic Testing, National Cancer Institute https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet
23. Unknown author, 10.07.2018, Prostate cancer, National Institute of Health Genetics Home reference, https://ghr.nlm.nih.gov/condition/prostate-cancer#inheritance
24. Unknown author, 10.07.2018, Lynch syndrome, National Institute of Health Genetics Home Reference, https://ghr.nlm.nih.gov/condition/lynch-syndrome#genes
25. Unknown author, 05.07.2016, Prostate cancer: Types and grades, Cancer Research UK, https://www.cancerresearchuk.org/about-cancer/prostate-cancer/types-grades
26. American Cancer Society editorial team, 15.08.2017, Tests for Prostate Cancer, American Cancer Society https://www.cancer.org/cancer/prostate-cancer/detection-diagnosis-staging/how-diagnosed.html
27. NHS editorial team, unknown date, Benign prostate enlargement; Treatment, NHS, https://www.nhs.uk/conditions/prostate-enlargement/treatment/
28. 27. NHS editorial team, unknown date, Erectile dysfunction, NHS https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/#treatment
29. Unknown author, 04.07.2016, Decisions about your treatment, Cancer Research UK, https://www.cancerresearchuk.org/about-cancer/prostate-cancer/treatment/decisions-about-your-treatment
30. American Cancer Society editorial team, 18.12.2017, Survival rates for prostate cancer, American Cancer Society https://www.cancer.org/cancer/prostate-cancer/detection-diagnosis-staging/survival-rates.html
31. Unknown author, 03.2015., Can I reduce my risk?, Prostate cancer UK, https://prostatecanceruk.org/prostate-information/are-you-at-risk/can-i-reduce-my-risk
32. American Cancer Society editorial team, 18.12.2017, Chemotherapy, American Cancer Society https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/chemotherapy/chemotherapy-side-effects.html
33. Fernando M. Safdie, Tanya Dorff, David Quinn, Luigi Fontana, Min Wei, Changhan Lee, Pinchas Cohen, and Valter D. Longo, 31.12.2009., Fasting and cancer treatment in humans: A case series report, Aging Journal https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2815756/
34. Gustav van Niekerk, Suzèl M. Hattingh, and Anna-Mart Engelbrecht, 14.11.2016., Enhanced Therapeutic Efficacy in Cancer Patients by Short-term Fasting: The Autophagy Connection, Frontiers in Oncology, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5107564/
35. Monique Aucoin, Kieran Cooley, Christopher Knee, Heidi Fritz, Lynda G. Balneaves, Rodney Breau, Dean Fergusson, Becky Skidmore, Raimond Wong, and Dugald Seely, 29.06.2016, Fish-Derived Omega-3 Fatty Acids and Prostate Cancer: A Systematic Review, Integrative cancer therapy https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5736071/
36. Jessica Whitburn, Claire M. Edwards, and Prasanna Sooriakumaran, 25.04.2015. , Metformin and Prostate Cancer: a New Role for an Old Drug, Current Urology reports, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5405102/
37. Soheila Khodadadi, Nafiseh Sobhani, Somaye Mirshekar, Reza Ghiasvand, Makan Pourmasoumi, Maryam Miraghajani, and Somayeh Shahraki Dehsoukhteh, 25.05.2017., Tumor Cells Growth and Survival Time with the Ketogenic Diet in Animal Models: A Systematic Review, International Journal of preventive medicine, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5450454/
38. Ye Kuang, Xiaoyun Han, Mu Xu, and Qing Yang, 13.04.2018., Oxaloacetate induces apoptosis in HepG2 cells via inhibition of glycolysis , Cancer Medicine https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5911603
39. Brian J. Altman, Zachary E. Stine, and Chi V. Dang, 29.07.2016., From Krebs to Clinic: Glutamine Metabolism to Cancer Therapy, Nature Reviews: Cancer, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484415/