Prostate Cancer Risk Factors

Overview

Prostate cancer is one of the most common cancers diagnosed in individuals assigned male at birth (AMAB) after the age of 45. Because prostate cancer grows slowly, it is not considered high risk. The exact cause of this type of cancer is not clear, however the extensive research available points to a variety of well-studied risk factors associated with its development. The main risk factors include age, race and genetics. If you or someone close to you is an AMAB individual and would like to understand what factors may increase the risk of getting prostate cancer, this article will provide you with some clarity about it.¹

What is prostate cancer?

Prostate cancer is a tumour of the prostate (a small gland) within the sexual reproductive system of AMAB individuals. In a healthy AMAB person, this gland functions to aid in ejaculation and produces alkaline fluid that makes up the semen. The prostate, among other urinary and reproductive organs, is the most susceptible to developing cancer. The prostate tumour usually arises from abnormalities in the epithelium, a cell layer that lines the prostate and other tubular organs within the body. Hence, 90% of prostate cancers are reported to be adenocarcinoma (epithelial cancer of organ/gland).²

Prostate cancer symptoms 

Prostate cancer progresses slowly and at earlier stages is most often asymptomatic. Otherwise, you may experience symptoms similar to those caused by a benign prostate tumour (hyperplasia) and these can include:

• Increased need for urination
• Waking up at night to urinate (nocturia)
• Difficulty in passing  urine and maintaining regular flow
• Blood in urine
• Pain/burning sensation around the urethra
• Erectile dysfunctions
• Pain during ejaculation

Other symptoms you may experience can be associated with the location and size of the tumour, and whether it is metastasised (cancer cells spread into other tissues) such as:

• Compression of the spinal cord (associated with tingling, paralysis or leg muscle weakness)
• Bone pain (especially those closer to the prostate such as the pelvis or back) ¹ 

Prostate cancer causes

Prostate cancer is caused either by somatic mutations or hereditary mutations. Development of this cancer has been linked to the mutations within:

• Genes BRCA1 and BRCA2 (genes important in DNA repair within cells)
• Tumour suppressor gene p53 (associated with metastasised prostate cancer)
• Other groups of genes such as congenital (present from birth) mutation of ataxia telangiectasia mutated (ATM) gene (also crucial in DNA repairs in cells)

However, the exact reason why these mutations happen is not yet fully understood.^{1, 3}

Prostate cancer risk factors

Prostate cancer risk factors are continuously being researched and emerging new studies point to various aspects associated with its development.

Genetics and family history

Genetics seem to be significantly involved in the risk of getting prostate cancer. Individuals who have inherited prostate cancer or have a history of prostate cancer in their family are highly likely to:

• Develop this cancer at a younger age
• Have an increased chance of cancer returning after treatment
• Have a higher risk of more severe and faster-progressing cancer

There is a higher chance you may develop prostate cancer, if your family members have suffered/are suffering from these cancers:

• Lynch syndrome (a form of hereditary bowel cancer)
• Breast cancer
• Ovarian cancer¹

Ethnicity

Studies also show that prostate cancer is a higher risk for people of African-American, Black-European and Caribbean descent as compared with other ethnic backgrounds. However, it is important to note that Black individuals from Africa have a 40% lower risk in comparison with African-American individuals, which indicates that environment, such as processed/nutrient-poor foods commonly eaten in developed countries, plays a factor as well.³

Diet

Various studies indicate diet's role in the risk of developing prostate cancer. A diet high in saturated animal fats has been shown to:

• Induce more carcinogens (cancer-causing matter) related to prostate cancer
• Increase the number of oxygen-reactive species in the body
• A larger number of inflammatory molecules
• Higher cell division rate

These aspects contribute to the risk of cancerous changes, especially cancer of the prostate. Other foods, nutrients, and dietary choices that may increase prostate cancer risk are:

• Red meat (due to chemicals released when heat processing)
• High calcium intake (through supplements and/or dairy products)
• Corn oil
• Vitamin deficiency (D, B9, B12)

Consumption of sweetened drinks and high amounts of alcohol regularly have been indicated as possible factors but research is not conclusive.^3,4

Obesity and height

Obesity or being overweight has been linked to more severe forms of prostate cancer in multiple studies. Obesity means having a body mass index (BMI) over 30, while overweight is a BMI between 25 and 30. People who are obese or overweight have a higher chance of their prostate cancer metastasising and a less favourable cancer prognosis.³ 

Research also indicates that your height may be a factor influencing the risk of developing prostate cancer. The taller you are the higher the risk, this is suspected to be due to larger amounts of insulin-like growth factor 1 (IGF-1) in early life. IGF-1 promotes cell replication which in turn may lead to more cancerous changes within the cells and support the growth of tumours in general.^{3, 5}

Exposure to chemicals

It has been found that individuals exposed to pesticides and other chemicals used in agriculture work have a higher likelihood of getting prostate cancer.⁴ Additionally, it’s been shown that exposure to Agent Orange, a herbicide that was used strategically in the Vietnam War, can increase the risk of developing prostate cancer as well as its severity and chance of metastasis. 

Another chemical associated with greater prostate cancer risk is bisphenol A (BPA) which used to be present in many plastic food and drink containers. The food and drinks can get contaminated with BPA over time and then be consumed by people, which consequently leads to exposure of the digestive tract to its carcinogenic effects. Lastly, chlordecone insecticide used in banana tree plantations has also been linked to an increased risk of prostate cancer in some studies, but genetics may have also played a role in these incidences.³

Other conditions and treatments

Inflammation of the prostate

Inflammation, especially chronic, has been found to increase the risk of prostate cancer, as inflammatory molecules promote cell division rate and reduce their death rate which in turn may advance tumour growth. Inflammation of the prostate gland (prostatitis) caused by either infection, physical injury, or chemical exposure is largely associated with prostate cancer. It is usually asymptomatic, but if symptoms are present, patients are often advised to undergo a biopsy which can potentially reveal prostate cancer.³

Sexual activity and sexually transmitted infections

Research indicates that if an individual starts sexual activity earlier in life, their risk of developing prostate cancer is higher. Even though frequent ejaculation is linked to a decreased chance of suffering from this type of tumour, a reduction in ejaculation doesn’t seem to increase this risk.^{1, 3, 4}

On the other hand, various sexually transmitted infections (STIs) may be associated with a higher likelihood of suffering from prostate cancer, for example:

• Chlamydia
• Human papillomavirus (HPV)
• Gonorrhea
• Syphilis
• Trichomonas vaginalis infection

T. vaginalis is a parasite that usually causes an asymptomatic infection that may affect AMAB individuals’ urethra and prostate. If it persists within the prostate and causes chronic inflammation, this in turn may lead to cancer development in this organ.^1,3

Summary

Prostate cancer is often diagnosed in individuals assigned male at birth (AMAB) after the age of 45. Typically, it progresses slowly and understanding its risk factors can help with early detection or prevention strategies. The prostate is a gland of AMAB individuals’ sexual reproductive system and its epithelial cells may turn cancerous leading to adenocarcinoma (prostate cancer). It is usually asymptomatic, but at later stages, patients may experience urinary symptoms (dysuria), sexual symptoms (erectile dysfunction) as well as nervous system issues (spinal cord compression). Several factors are associated with a higher risk of developing prostate cancer such as genetics (family history of cancers), ethnicity, diet high in animal fats, obesity, being tall, exposure to chemicals (e.g. bisphenol A (BPA)), chronic inflammation and sexually transmitted infections. Knowing what the risks are may be helpful to you or your loved one and the healthcare provider to understand individual risks and provide you with some preventive strategies.

FAQs

Is prostate cancer the most survivable cancer?

Prostate cancer is one of the most “survivable” cancers as it progresses slowly. In the UK, 95% of individuals with prostate cancer will survive 1 year after diagnosis, 85% will survive 5 years after diagnosis, and almost 80% will survive 10 years after diagnosis.⁶

Is prostate cancer less aggressive after the age of 70?

No, on the contrary, as you age, your chances of developing prostate cancer get higher and older individuals are at a higher risk of the cancer being more aggressive and severe. Hence, early screening is of great importance.⁷

What is the best predictor of prostate cancer?

Prostate-specific antigen (PSA) test is the most common tool for detecting prostate cancer and tracking its progress. PSA protein is produced by the prostate and released into the bloodstream. If the levels are found to be consistently high, then further exams (rectal examination, biopsy, imaging) may be recommended to check for tumours.